Knee

ACL

A Assessment

 

ACL Normal ArthroscopyACL Normal Arthroscopy

 

Anatomy

 

Developmental Anatomy

 

Knee joint first appears as a mesenchymal cleft at 8 weeks gestation

- ACL and PCL separate entities by week 10

- cruciates principle determinants of  shape of tibiofemoral articulation 

 

Histology

 

Collagen and elastin arranged in less parallel configuration than tendons

- allows increase in length without large increase in internal stress

 

Ligaments attach to bone directly or indirectly

 

Cruciates attach directly / 4 histological zones

- ligament

- nonmineralised fibrocartilage

- mineralised fibrocartilage

- cortical bone

 

Indirect attachments via periosteum and fascia

- i.e. tibial insertion of MCL

 

Gross Anatomy

 

Intracapsular and extra-synovial

 

Direction

 

In full extension ACL

- subtends 45o angle in sagittal plane

- 25o angle in coronal plane

 

Dimensions

- 25-40 mm long

- 7-10 mm wide

 

Bundles

 

Anteromedial and posterolateral bundles

- described regarding point of tibial insertion

 

Anteromedial

- smaller

- tight in flexion

- test with anterior draw

 

Posterolateral

- larger

- tight in extension

- test with Lachman / Pivot Shift

 

Nerve

-  posterior articular nerve / branch tibial

 

Arterial supply 

- middle geniculate   

 

Origin

- medial wall LFC

- semicircular

- semicircular proximal insertion high and posterior on medial wall of LFC

 

Insertion 

- passes anteriorly, distally and medially

- oval shaped fossa anterior and between the tibial spines

- majority of ligament passes deep to transverse meniscal ligament

- a few fascicles blend with anterior horn of lateral meniscus

- variable and minor attachment to the posterior horn of the lateral meniscus

- wider and stronger than femoral insertion

 

Function

 

1° Stabilizer

- prevents anterior translation

 

2° Stabilizer

- lateral & medial stability

- protector of menisci

 

4 important features of function

 

1. Carries load throughout entire range resisting AP and translational forces

- different fibres recruited at different times 

 

2. Carries only small loads during normal activity

- about 20% of failure capacity during normal loading

 

3. Highest loads are produced by quadriceps powered extension of knee (open chain exercises)

- but during any one exercise failure loads only reach about 5%

 

4. Much more complex behaviour than just a series of fibres

- exhibits viscoelastic properties allowing it to adapt to different loading patterns

- ACL consists of many fascicle subunits

- these are recruited as needed to accommodate strain

 

Incidence

 

1:1500 - 1:3500

 

Mechanism

 

Non contact deceleration producing valgus twisting injury

 

Deceleration / ER / Valgus

 

Associated Injury

 

Meniscal Injury

 

60% lateral meniscus

- associated with acute ACL rupture

- classically posterior horn

- many will heal

 

Lateral Meniscus Posterior Horn Tear Post ACL RuptureLateral Meniscus Posterior Horn Tear Post ACL Rupture

 

40% medial meniscus

- associated with chronic ACL rupture

 

Fractures 

- 10-20%

- assciated with characteristic bone bruise patterns  on MRI

- see femoral chondral impressions from hyper-extension injury

 

Lateral Femoral Condyle Impaction Post ACL InjuryLFC Bone Bruise

 

Chondral Injuries

 

Chondral Lesion Post ACL InjuryChondral Lesion Post ACL Injury

 

MCL 

- 10-20%

 

History

 

1.  50% describe a "Pop"

 

2.  75% haemarthrosis

- intraarticular swelling or effusion within the first 2 hours after trauma suggests hemarthrosis

- swelling that occurs overnight usually is an indication of acute traumatic synovitis / meniscal tear

 

3.  Immediate inability to weight bear

 

DDx hemarthrosis 

 

Rupture of a cruciate ligament

Osteochondral fracture

Peripheral tear in the vascular portion of a meniscus

Tear in the deep portion of the joint capsule

 

Examination

 

Laxity Grading Lachmans / Anterior Draw

 

1+: mild instability < 5mm

2+: moderate instability 5-10mm

3+: severe instability >10mm

 

Lachman's 

 

20 - 30° Flexion

- removes effects of bony contour / menisci i.e. 2° constraints

- stabilise femur with one hand, other hand behind tibia with anterior force

- sublux the tibia forward

 

85% sensitivie when awake 

100% under anaesthetic

 

Lachmans PreLachman's Post

 

Anterior Draw

 

Knee at 90° Flexion with hamstring relaxed

- foot in neutral

- sit on foot to stabilise

- hands behind tibia and pull forward

- has to > 3mm different to contralateral knee

 

Anterior drawer 1Anterior Drawer 2

 

Foot in 15° of External Rotation

- medial structures tightened in this position

- reassess anterior draw

- if have positive anterior draw in this position suggests associated posteromedial injury

- ACL + MCL / Med Capsule / OPL

 

Foot in 30° of Internal Rotation

- lateral structures tight in this position

- reassess anteior draw

- if have positive anterior draw in this position suggests associated posterorlateral injury

- ACL / LCL / PLC Complex 

 

Pivot Shift

 

Concept

- ACL torn

- lateral tibia subluxed anteriorly in extension

- reduced in flexion

 

Technique

- knee moves from extension to flexion

- valgus force applied to knee

- apply axial load

- mimicking weight bearing

 

Findings

- in extension the LTC is subluxed anteriorly

- in extension ITB is in front of flexion axis and is extender of knee

- as the knee is flexed

- ITB moves behind the flexion axis and becomes flexor of knee (20-40°)

- this reduces the LTC

 

“The relocation of the subluxed lateral tibial condyle as the extended knee is flexed”

“This occurs as the ITB line of function changes so as to become a flexor rather than an extensor of the knee”

 

Lachman 1Lachman 2

 

Need 4 things for a pivot shift

1. MCL to pivot about

2. ITB to reduce on flexion

3. Ability to glide ie no meniscal tear

4. °FFD

 

Grading

 

Jakob et al JBJS Br 1987

- 3 grades with foot in varying degrees of rotation

 

Grade 1:  Pivot shift with foot IR

Grade 2:  Pivot shift with foot neutral

Grade 3:  Pivot shift with foot ER

 

X-ray

 

Usually normal

 

Segond Fracture

- small avulsion fracture of lateral proxima tibia

- is sign of lateral capsular avulsion

- pathognomonic of ACL tear

 

ACL Segond

 

Tibial avulsion

- more common in children

- can be seen in adults

 

ACL Bony Avulsion XrayACL Bony Avulsion CTACL Bony Avulsion AdultACL Bony Avulsion Sagittal MRI

 

MRI

 

Normal ACL on MRI

 

 Intact ACL T2Intact ACL T1MRI Normal ACL

 

Characteristics

- straight structure

- parallel to intercondylar notch

- no anterior subluxation of the tibia

- normal to have some increased signal due to adipose and synovial tissue

- able to see continuity of fibres from tibial to femur

 

Not always accurate

- ACL is helicoid shape

- sagittal MRI alone inaccurate in 10 - 20%

- sensitively increase to > 95% by using coronal and axial images

 

Torn ACL on MRI

 

ACL MRI Femoral ACL AvulsionACL MRI Rupture T2

 

Findings

- high signal intensity / oedema in ACL, especially accutely

- unable to identify continuous fibres from tibial to femur

- loss of taut, straight line of fibes

- loss of attachment onto LFC on axial

 

ACL Femoral Avuslion MRI

 

May see stump of ACL

 

ACL Torn with remnant stump MRI

 

May identify ACL healed onto PCL

 

MRI ACL torn and healed on PCL

 

May see tibia subluxed anteriorly

 

ACL Partial Tear

 

ACL Partial Tear

 

Bone bruising patterns

- pathognomonic

- caused by the knee pivot shifting

- terminal sulcus of LFC

- posterolateral tibial plateau

 

MRI ACL Rupture Bony Oedema Lateral Femoral CondyleMRI ACL Rupture Bone Oedema Terminal SulcusMRI ACL Rupture Bone Oedema Posterolateral Tibia

 

Mechanical Testing

 

KT 1000 

- Instrumented Lachman's and Anterior Draw

- > 3mm c.f. other knee 98% sensitive

- > 10mm absolute on one side

 

Arthroscopy

 

ACL Partial Tear ArthroscopyArthroscopy Empty Lateral Wall

 

ACL Rupture Empty Lateral WallRuptured ACL

 

Findings

- empty lateral wall

- ACL healed onto PCL

- partial tears

- ACL healed onto different part of LFC

B Management Options

NHx

 

Natural History of ACL deficient knee is variable

- functional instability 15% - 90%

- progression to OA is variable

 

Depends on level of patient demands / activity

 

1.  Late meniscal injury in ACL deficient knee

 

15-25%

 

2.  Function

 

Daniels Am J Sports Med 1994

- 292 ACL defecients knees

- 50% of patients not reconstructed returned to sport / most at reduced level

 

Frobel et al NEJM 2010

- RCT of 120 patients

- early ACL reconstruction or functional rehab with option of delayed reconstruction

- no difference between two groups

- 1/3 of patients in ACL rehab group chose to have ACL reconstructed

 

3.  Osteoarthritis

 

Daniels Am J Sports Med 1994

- higher OA in reconstructed knee v non operative

- even if remove those knees that had meniscal surgery

 

Shelbourne

- no OA in 97% of ACL reconstructed patients at 5 – 10 year follow up if

- no meniscal damage and normal cartilage at time of surgery

 

Pinczewski 

- 20% rate of OA in HS patients at 10 years

- higher in BPTB ligament

 

Non-operative Management

 

Indications

 

Patient able or willing to modify activities

No functional instability

 

Management

 

Acute phase

 

RICE, Analgesics

Weight bear as tolerated 

 

ROM exercises started early

- aim to regain full flexion & extension early

 

Muscle-strengthening

- started once FROM achieved

- quads & hamstring

- closed chain exercise

 

Resumption of sport

 

ACL rehabilitation protocol

 

Assessment

- quads and hamstring strength 90% other side

- able to perform single leg hop > 1m

 

Non-ACL Stressing ie. Bike / Swimming best

 

Avoid ACL Stressing activities

- pivoting sports

- open chain quads

 

ACL brace

- for pivoting sports

 

Operative Management

 

Indications

 

Recurrent symptomatic instability

Desire to return pivoting sport and inability to do so

 

+/- Repairable meniscus

- meniscus more likely to heal in setting of ACL Reconstruction

 

1.  ACL +  Torn Menisci 

 

Meniscal Repair

 

1.  ACL + Meniscal repair

- 60-70% success of meniscal repair without concomitant ACL reconstruction

- 90% success if repair meniscus & ACL together

 

2.  Timing 

- acute meniscal repair does better than delayed repair

- 90% heal if <8/52

- 70-80% heal if >8/52

 

3.  Side

- more medial than lateral are repairable

 

Meniscectomy 

 

Known to predispose the knee to poorer outcome

 

Kartus et al Acta Orthop Scanda 2002

- multicentred trial of over 400 patients having ACL reconstruction

- compared normal meniscus to patients who had > 1/3 meniscus removed

- meniscectomy group had more pain / swelling / laxity

- meniscectomy group had worse knee scores and more likely to have reduced ROM

 

2.  Acute locked knee & ACL 

 

Definition

- inability to flex / extend knee

- due to flipped bucket handle meniscus

 

Pseudolocking

- ACL stump causing FFD

- arthroscopy to remove blockage

 

MRI

- Confirm locked bucket handle meniscal tear

 

Need to unlock knee

 

Options

 

1.  Arthoscopy / reduce meniscus / rehab / repair both at 6 weeks

- avoids risk of arthrofibrosis

- two surgeries required

- may be best if patient has a FFD

- however the meniscus may redisplace

 

2.  Repair meniscus / rehab /  reconstruct ACL later

- problem is reduced rate of meniscus healing

- an unstable knee may retear the meniscus

 

3.  Acute ACL reconstruction and meniscal repair

- advantage is single surgery / high rate meniscus healing

- problem is risk arthrofibrosis

 

3.  Medial Collateral & ACL

 

Epidemiology

 

Grade II MCL

- 75% chance ACL rupture

 

Non-operative

 

Rehab MCL

- perform delayed reconstruction of ACL if symptomatic instability

 

ROM knee brace to limit extension

- 2 weeks 30-60°

- 2-4 weeks 30-90°

- 4-5 weeks 15˚ - 90

- 6th week 0 – 90˚

 

Indication for surgery

- MCL torn off tibia (usually off femur) and flipped up and over the pes anserinus

- won't heal in this position

- MRI all patients with MCL tenderness over tibal insertion

 

Patient with MCL and ACL instability

- reconstruct ACL

- reassess MCL at end of case

- if mildly unstable, advance / imbricate MCL on femoral side +/- tighten medial head gastrocnemius

- if severely unstable, reconstruct with hamstring or tendoachilles allograft

 

MCL Advancement

 

4.  ACL + large medial chondral lesion

 

Consider HTO + ACL

 

ACL HTO APACL HTO Lateral

 

Surgical Options

 

1.  Primary Repair

 

High failure rate

 

Reason

1. No clot formation 2° synovial fluid

2. Tension on ligament

3. Intrinsically poor healing potential

 

2.  Extra-Articular Augmentation

 

Lateral extra-articular procedures 

- prevent anterior subluxation LFC in extension

- unpopular due to poor long term results

 

1.  Ellison Procedure

 

A.  Strip of ITB Deep to LCL 

- placing it anterior in a bone trough

B.  Plication the capsular ligament

 

2.  MacIntosh Procedure

 

ITB left attached distally

- deep to LCL

- subperiosteal tunnel in LFC

- thru intermuscular septum

- back on itself distally

 

ACL Ellison APACL Ellison LateralMacIntosh ACL Scar ITB

 

3.  ACL Reconstuction

 

Graft Incorporation

 

1.  Central necrosis 

- 6 weeks post op

- strength of the graft if 70% of original at this time

 

2.  Synovialisation

- up to 6 months post op

 

ACL Graft 6 months0001ACL Graft 6 months0002

 

3.  Revascularisation

 

4.  Ligamentisation 

- 6 to 18 months

- longitudinal orientation of collagen

- normal tendon at 2 years

 

Theory

- acts as scaffold for fibroblasts

- graft undergoes ischaemic necrosis & then becomes enveloped with vascular synovial tissue

- occurs at 4-6 weeks post-op

- neovascularisation & cellular proliferation 3/12

 

 

C Surgical Reconstruction Issues

Timing of Surgery

 

Issue

- reported higher incidence with immediate reconstruction in acute phase

- reduced by settling inflammation / effusion and obtaining FROM

- always best to delay if not professional athlete

- problematic if patient has locked bucket handle mensical tear

 

Results

 

Bottoni et al Am J Sports Med 2008

- RCT of early (average 9 days) v late reconstruction (average 85 days)

- no difference between the two groups

 

Autograft Choices

 

Middle 1/3rd BPTB

 

ACL BPTB IncisionsBPTB GraftACL BPTB

 

Potential Advantages

- stiffer / perhaps increased strength and stability in contact athlete

- potentially better fixation because of bone blocks

 

Disadvantages

- risk of patella fracture

- increased anterior knee pain when kneeling

 

ACL BPTB Patella Fracture APACL BPTP Patella Fracture LateralACL BPTB Patella ORIF APACL BPTB Patella ORiF Lateral

 

4 Strand Hamstring Graft

 

Advantage

- little functional deficit

- mild knee flexion weakness

- less PFJ pain

 

Disadvantage

- ? more post operative laxity

- some weakness of hamstrings which may be important in some athletes

 

Contra-indications

- generalised ligamentous laxity

- sprinters

- hamstring injury

 

Hamstring v BPTB

 

Results

 

Spindler et al Am J Sports Med 2004

- systematic review

- no significant difference in graft failure between the two groups

- increased kneeling pain in BPTB group

 

Blau et al BMJ 2006

- meta-analysis

- some weak evidence that BPTB provides increased stability

- some evidence of lower morbidity in HS

 

Reinhardt et al Orthop Clin North America 2010

- level 1 systemic review

- failure defined as 2+ Pivot shift or revision surgery

- HS significantly higher failure rate

- significantly higher values of anterior laxity in HS

- significantly higher incidence of extension deficits in BPTB

 

3.  Allograft

 

Options

- achilles

- BPTB

- quads tendon

- tibialis anterior / posterior

 

Advantage

- nil graft site morbidity

 

Disadvantage

- disease transmission 

- high costs ($5000 per graft)

- slower incorporation (Return at 12/12 vs 6/12)

- increased failure rate

 

Results

 

Mehta et al Orthopedics 2010

- retrospective review of allograft v autograft BPTB

- 9% v <1% failure rate

 

Sun et al Arthroscopy 2009

- RCT of allograft v autograft BPTB in 156 patients

- average follow up 5 years

- no significant difference between the two groups

 

Indications

- revision

- older, lower function patients

 

4.  Synthetic

 

Advantage

- no donor site morbidity

 

Disadvantage

- poor history with regards rupture and synovitis

 

Results

 

Gao et al Arthroscopy 2010

- 159 patients followed for average 4 years

- average side to side difference 1.5 mm

- 93% satisfied or very satisfied

- 3 ruptures, one of which developed synovitis

 

Tunnel Placement

 

1.  Intra-operative tunnels

 

Isometricity does not exist

- no point on femur that maintains fixed distance from point on tibia

- up to 3 mm elongation acceptable

- graft should tighten with increased extension

 

A. Tibial tunnel 

 

Sagittal plane

- 7 mm anterior to PCL & central

- posterior 1/2 ACL footprint

 

Coronal plane

- 2/3 way towards medial tibial spine from anterior horn of lateral meniscus

 

Tunnel angle

- usually 55o

- reduce angle to shorten tunnel if have short graft

 

B. Femoral tunnel 

 

More vertical placement of tunnel

- increased AP stability

- less rotational stability / pivot shift

 

Coronal plane

- 2 o'clock rather than 1 (right knee)

- 10 o'clock rather than 11 (left knee)

 

Sagittal plane

- want to be posterior

- identify back wall in flexion

- want 2mm of back wall behind tunnel

 

2.  X-ray assessment

 

Lateral x-ray

 

Femoral tunnel

- intersection of line posterior femoral cortex and Blumensaat's line

 

Tibial tunnel

- posterior to Blumensaat's line in full extension

- parallel to Blumensaat's line

 

ACL Reconstruction Femoral Tunnels SagittalACL Reconstruction Sagittal Tibial Tunnel

 

Pinczewski JBJS Br 2008

- 200 patients followed up over 7 years

 

1.  Posterior femoral tunnel placement

- 86% along Blumensaat's line 

 

2. Anterior tibia tunnel placement

- 48% along tibial plateau

- parallel to Blumensaat's

 

ACL Reconstruction Sagittal Tunnel Measurement

 

AP Xray

 

1.  Medial tibial tunnel placement

- 46% (towards medial)

 

2.  Lateral femoral tunnel placement

- 42% from lateral LFC

 

3.  Graft inclination

- 19o

 

ACL Reconstruction AP Tunnel MeasurementsACL Reconstruction Graft Inclination Measurement

 

11% rupture rate over 7 years

- associated with posterior tibial tunnel placement

 

Good rotational stability

- 19o inclination in coronal plane

- avoid too vertical orientation

 

3.  Incorrect tunnel positions

 

Tibial Tunnel

 

A.  Anterior tibial tunnel

- impingement / limits extension / cyclops lesion

 

B. Posterior tibial tunnel

- impinge on PCL

- extension strain in extension

 

C.  Lateral tibial tunnel

- impinges on lateral wall femoral condyle

 

Femoral Tunnel

 

A.  Anterior Femoral Tunnel

- limits flexion

- increased strain in flexion / stretches graft

- increases risk of failure

 

B.  Posterior Femoral Tunnel

- excessive strain in extension

 

C.  Vertical Graft

 

Fu etal Arthroscopy 2003

- cadaver study of graft in 10 v 11 o'clock position

- demonstrated increased rotational instability in 11 o'clock

 

Options for drilling femur

 

1.   Trans - tibial 

 

Traditional techique

- drill tibial tunnel first

- place guide up tibial tunnel onto femur

 

ACL Transtibial Tunnel

 

Advantage

- cannot damage MFC

 

Potential disadvantage

- tibial tunnel sets position of femoral tunnel

- tends to make the graft more vertical

 

Technique

- drill femur with knee at 90o

 

2.  Anteromedial portal

 

Advantage

- allows separation of femoral from tibial tunnel

- can place femoral tunnel lower on femoral wall

 

ACL Anteromedial Femoral Tunnel

 

Disadvantage

- places drills and reamers close to MFC

- must be careful not to damage cartilage

 

Technique

- must hyperflex knee

- or femoral tunnel may exit in PFJ

 

Femoral Tunnel Back wall blow-out

 

Problem

 

Cannot use RCI screw to secure femoral side

 

Avoid by

 

1. Using posterior offset femoral guide

- divide tunnel size required in half and add 2

- 6mm for 7.5 mm hamstring tunnel

- 7mm for 10 mm BPTB tunnel

 

2.  Appropriate knee flexion when drilling femoral tunnel 

- hyperflexing knee if using AM portal

- 90o of flexion if using transtibial technique

 

Options

 

1.   Endo-button 

- don't need back wall for fixation

 

2.  Redrill tunnel 

- change angle by flexing knee +++

- get in good bone stock

 

3.  Fix in over the top position

- pass graft around back of femoral condyle using curved hemostat

- may need medial parapatella approach

- lateral approach to femur

- fix to femur with screw / staple

- can pass around lateral intermuscular septum and LCL

 

Notchplasty

 

ACL Large Notch OsteophyteACL Post Notchplasty

 

Issue

- smaller notch increases risk of re-rupture / stretching by causing graft impingement

- more necessary with larger grafts i.e. BPTB

- required if presence of notch osteophytes

 

Disadvantage

- notchplasty can lateralise

- important to only debride anterior portion of notch

- do not debride lateral wall or will lateralise the femoral graft

 

Techique

- trial with guide wire / reamer / chondrotome / graft

- check for lateral wall impingement

- check for roof impingement

- notchplasty as required

 

Graft Fixation

 

Graft fixation is weakest link first 6-12 weeks

- BPTB 6-10 weeks to incorporate

- HS 12 weeks (bone grows into tendon resembling Sharpey's fibres)

 

After 12 weeks the weak link is the graft

 

Options

 

Aperture Fixation

 

Interference screw

- metal / bioabsorbable

 

Suspensory Fixation

 

Endobutton

Transfix

 

ACL Transfix Pin

 

Fauno et al Arthroscopy 2005

- compared transfix and endobutton

- demonstrated increased tunnel widening with fixation away from joint i.e endobutton

 

Screws

 

Diameter

- biomechanical studies in tibia with hamstring

- line to line screw size less strong than tunnel diameter + 1

 

Length

- probably more important than diameter in hamstring

- has been demonstrated than increasing length increases fixation

- increase number of threads available for fixation

 

Divergence

- important with bone block

- must keep divergence below 200

 

Central / eccentric placement

- no significant difference

 

Metal v bioabsorbable

 

Mascarenhas Arthroscopy 2015

- meta-analysis

- no difference in outcome

- increased knee effusion, femoral tunnel widening, and screw breakage with bioabsorbable

 

Single v Double Bundle

 

Issue

 

Recurrent instability of 10-20% with single bundle

- normal ACL double bundle

- single bundle restore AP > rotatory stability

- can alter this by reducing graft verticality in coronal place

 

Disadvantage

- technically difficult

- twice as many tunnels to get wrong

- longer surgical time

- difficult revision

- no proven advantage clinically

 

Results

 

Kondo et al Am J Sports Med 2008

- prospective cohort study of 328 patients

- single v double bundle

- double bundle patients had significantly reduced anterior and rotational laxity

- no difference in clinical outcome or knee scores

 

 

D Surgical Techniques

Achilles Allograft

IndicationsAchilles Tendon Allograft

 

Revision

Multi-ligament injury

Older patient

 

Technique

 

Graft preparation

 

Calcaneal bone plug for femoral tunnel

 

Prepare bone plug

- decide on bone graft size needed

- 12 mm wide if revision / 10 mm if primary

- 20 mm long

- 10 mm deep

 

Cut with microsagittal saw

- take central third

- trim to size

- ensure passes nicely through cylinder

- no sharp edges

- drill holes as per normal bone block, 2 x 1 ethibond sutures

 

Achilles Allograft Saw Bone Block 1Achilles Allograft Saw Bone Block 2Achilles Bone Block Saw 3

 

Tendon

- 12 mm wide in man

- 10 mm in woman

 

Keep tendon long

- no need to cut short

- can cut at end of case

- the tendon will remain outside of knee

- fixate this end with Kochers

- no sutures required

 

Achilles Tendon Allograft Final

 

Tunnels

 

Drill tunnels as per standard technique

- beath pin in femur

- drill desired depth to 5 mm more than bone graft length

- eg 25 for 20

- line to line diameter

 

Fixation

 

Pass graft

 

Femoral fixation

- fix with 9 x 25 mm screw if 12 mm tunnel / graft

- otherwise 7 x 25 mm tunnel if 10 mm tunnel / graft

 

Tension graft

 

Tibial fixation

- 9 x 35 mm screw

- augment with staple

 

 

 

 

BPTB Allograft

Graft Preparation

 

BPTB Allograft Initial

 

Defrost

- in 2 litres normal saline

- can add vancomycin powder

 

Choose which part of graft to use

- usually central third

- can take either side

- try to leave sufficient graft in case of disasters

- i.e. dropping or rupturing graft

 

BPTB Allograft Tendon Cut

 

Cut tendon with knife

- 10 mm thick in women

- 12 mm thick in men or revisions

- adjust to patient's size and needs

 

Cut soft tissue on patella / tibial tuberosity ends

- usually narrow graft so becomes 10 mm wide

- can make 12 mm wide in revision setting

 

Length of bone femoral side

- usually 20 mm on femoral side

- this is usually from the patella

- cut with saw on each side

- turn and cut so is 10 mm thick

- ensure this end fits nicely through 10 mm / 12 mm tube

- this will be the passing end

 

BPTB Allograft Saw 1BPTB Allograft Saw 2

 

Length of bone on tibial side

- depends on fixation method

- risk is donor-recipient mismatch

- best to keep this side long / take from tibial end of graft

 

Graft mismatch

- if donor tendon too long for recipient knee, all bony graft will be outside tunnel

- if too short, a lot of the bony graft will be pulled into tunnel

- so keep bone graft long

- at least 30 mm

- can always shorten the tibial graft end if needed

 

BPTB Allograft Final 1BPTB Allograft Final 2

 

Drill holes x 2 in each bony block

- pass 1 ethibonds x 2 with suture passer

- tension

 

Tunnels

 

Standard tunnels via preferred technique

- tunnel diameter line to line

- femoral tunnel 5 mm deeper than bone bloc

 

Tibial fixation

- prepare a tibial groove

- using saw

- in tibia from drill hole inferiorly

- 1 cm wide, 3 cm long

- so that can secure excess tibial bone block down into this groove

 

Graft fixation

 

Pass graft

 

Fix femoral graft

- 7 x 25 screw for 10 mm graft

- same for 12 mm graft

 

Tibial graft

- either pass screw 9 x 25 mm (10 mm tunnel)

- can fix into tunnel with staples (small or medium richards)

 

ACL BPTB Allograft LateralACL BPTB Allograft AP

 

 

 

 

 

BPTB Autograft Transtibial

Harvest graft

 

BPTB IncisionBPTB ParatenonBPTB Expose TendonBPTB Measure Central Third

 

Midline incision over patella tendon

- from lower pole of patella to tibial tuberosity

- dissect fascia off tendon carefully without injuring tendon

- identify medial and lateral margins and assess tendon width

 

BPTB Central ThirdBPTB Medial CutBPTB Medial Cut 2BPTB Lateral Cut

 

Use marking pen to mark central 1 cm of tendon at distal pole patella

- can increase this to 12 - 14 mm in large male if sufficient tendon width

- use knife to cut from 2 cm on patella down medial side

- ensure leave 5 mm tendon medially

- extend 2cm down tibial tuberosity

- remeasure and cut laterally

 

BPTB Tibial Incision 2 cm longBPTB Saw CutBPTB Elevated Bone Block

 

Bone blocks

- measure 2 x 1 cm bone block on tibial tuberosity

- cut each side at 45o with saw

- 1cm deep with each saw cut meeting as triangle

- distal transverse cut 1cm deep

- lever out with curved ostetome

- make 2 x 1.5 cm drill holes with piece in situ, mark with pen

 

BPTB Patella BoneBPTB Patella SawBPTB Patella ElevationBPTB Drill in Situ

 

Repeat on patella side, can push patella down for exposure

- use smaller lever on patella side and be more delicate

- remove graft carefully, have to dissect off the fat pad

 

BPTB Graft

 

Graft preparation

 

ACL BPTB GraftACL BPTB Graft 2

 

Clean tendon of soft tissue

- decide which end will pass into femur

- usually the smaller piece

- nibble any sharp edges off especially on leading edge

- ensure whole graft will pass through 10 mm tube

- decide which end will be tibial or femoral

- mark femoral end with blue pen

- put 2 x 1 non absorbable sutures through drill holes

- probably don't need to tension BPTB

 

Knee arthroscopy

 

Medial portal

- soft spot

- make larger as need to insert 7 mm screw through here

- clean thoroughly with shaver

 

Prepare LFC

- notchplasty often required

- graft is significantly larger than HS

 

Tunnels

 

Tibial tunnel

- tibial jig / beath pin / 10 mm reamer

- need to ensure sufficient distance anterior to PCL

- use shaver to clean tunnel, especially entrance

 

ACL Tibial GuideTibial Beath Pin

 

Transtibial femoral tunnel

- need to use 7 mm offset jig to prevent posterior wall blowout

- pass femoral beath pin at 90o

- drill femoral tunnel 10 mm wide

- 5mm deeper than bone graft length

- if bone plug 20 mm long, drill 25 mm

- if bone plug 25 mm long, drill 30 mm

- need to thoroughly clean tunnel of bone debris

- can help to pass acorn reamer twice

 

ACL Femoral Offset GuideACL Transtibial Beath Pin 1ACL Transtibial Beath Pin 2ACL Femoral Acorn Drill


Graft

 

Pass loop 1 PDS though tip of beath pin

- pull 4 sutures of lead bone plug through

- advance the beath pin out of the femur

- secure sutures

 

Pass graft

- ensure bone plug passes easily into tibial tunnel

- pull up gently on sutures and advance the bone plug into knee

- use grasper to align the bone plug with the femoral tunnel

- then pull on sutures and advance the plug into the tennel

- pull femoral bone plug deep into tunnel and tension

 

Screw Fixation

 

Femoral screw

- need to be careful ans can blowout back wall or create divergent screw

- hyperflex knee +++

- this step is very important to prevent divergent screw

- expose femoral tunnel with good vision

- pass screw guide wire anterior to bone graft so as not to blow out tunnel

- insert 7 x 25 mm screw ensuring that the screw threads engage the tunnel

 

ACl Femoral Screw Guide WireACL Femoral ScrewACL BPTB in situ

 

Trial

- check no impingement

- tension tibial side at 30o

- insert 9 x 25 mm screw

 

ACL No Impingment full extension

 

Post Op xrays

 

ACL BPTB Autograft LateralACL BPTP Autograft APACL BPTP Autograft Skyling

 

 

 

 

Hamstring Graft Anteromedial

Endobutton + Interference screw +/- staple or post

 

ACL Reconstruction Hamstring Endobutton RCI Screw APACL Hamstring Graft

 

Advantage

- endobutton simple yet strong fixation

- endobutton eliminates problem if blow out back wall

- can still use femoral RCI screw if run into problems with endobutton

 

Set up

 

GA, tourniquet, IV antibiotics

- knee roll, lateral support

- knee at 90o for optimum access to notch

- but need to be able to hyperflex for femoral tunnel

- EUA to confirm positive pivot shift

- +/- pressure pump

 

Harvest graft

 

Knee flexed 90o

- usually roll tendons under finger

- longitudinal incision

- 2cm below joint line / 2 cm medial to crest / 2 cm long

- superior aspect of incision at level of tibial tuberosity

- separate skin and subcutaneous fat

- view sartorius fascia

- roll tendons again

- use knife and make cut above and parallel to gracilis

- elevate fascial flap

- used curved hook, identify both tendons first

- isolate gracilis (say Grace before Tea)

- divide vinculae (usually one)

- use tendon harvester in straight line aiming towards ischial tuberosity

- isolate ST, divide larger vinculae (there is nearly always two), strip

 

Hamstring 1Hamstring 2Hamstring 3Hamstring 4

 

Prepare graft

 

Leave tendons attached to tibia or remove and prepare on table

- remove muscle with scissors / spoon

- loop both tendons through endobutton to create 4 strand

- can suture all 4 ends together or do each 2 separately

- no 1 ethibond / ticron / fibrewire

 

Tensioner

- 10 - 15 lb

 

Hamstring Graft Tensioned

 

Endobutton Choices

 

30mm / 20mm / 15mm loops

- if shorter graft / longer tunnel use longer lopp

 

Size graft

 

Will be usually 7.5 - 8.5 mm in man

- 6.5 - 7.5 in woman

- ream a tunnel to the same size as the graft

- a tight tunnel fit may mean less fluid to cause tunnel widening

- will potentially make passing the graft / flipping the endobutton harder

 

Arthroscopy

 

Lateral portal

- high and midline

- need to be able to see around corner medial wall of LFC

 

Medial portal

- low and midline

- if too medial risk damaging MFC with reamers

- too lateral means graft too vertical

- low position gives good angle on femoral tunnel

- best to trial with needle first

 

ACL Reconstruction Anteromedial Portal

 

Assess and manage mensicus as appropriate

- assess and manage chondral lesions as appropriate

 

Debride ACL

 

Debride stump back to PCL fibres (preserve synovium over PCL)

- can leave some stump to identify tibial tunnel and provide vascularisation

- clean lateral wall

- remove periosteum with curette, chondrotome and electrocautery

- identify resident's ridge and posterior wall clearly

 

ACL Stump ArthroscopyACL Stump Arthroscopy

 

ACL Clear Lateral WallACL Identify Back Wall

 

Femoral tunnel

 

Entry Point

- 1.30 o'clock on R, 10.30 o'clock on L

- 6 mm offset guide through anteromedial portal

- aim to leave 2 mm posterior wall

 

Femoral tunnel beath pin

- hyperflex knee, pass beath pin

- if don't hyperflex, tunnel can be very long

- want wire to emerge anterior to lateral intermuscular septum

- if tunnel too vertical, can emerge in PFJ

 

ACL Reconstruction Long Femoral TunnelACL Reconstruction PFJ APACL Reconstruction Lateral

 

Femoral Tunnel Drilling

- pass 4.5mm endobutton drill completely through femoral cortex

- remove beath pin and insert depth gauge

- measure femoral tunnel (between 34 and 46 mm)

- drill appropriate sized tunnel with acorn reamer to within 10mm of cortex (for 20 mm endobutton)

- gives room to pull through and flip 10 mm endobutton

- if 15 mm endobutton need to be within 5 - 7 mm

- carefully clean out all bone fragments with shaver / depth gauge or may prevent graft passage

- insert loop 1 nylon to pass graft later

 

ACL Anteromedial Beath PinACL Femoral Acorn Reamer

 

If blow out cortex, can also use extended endobutton

- wider than 10 mm

- often when this is pulled through, will go too far and lodge in vastus lateralis

- in which case cut down to endobutton and seat securely on femur

 

Tibial tunnel

 

Use drill guide set at 55o

- use < 55o if short graft

- entry medially through hamstring incision

- set for wire to exit either tip or elbow

- anterior to PCL

- posterior half of ACL stump

- identify medial tibial spine and anterior horn of lateral meniscus

- 2/3 along this line towards medial tibial spine

- pass beath wire

- drill tunnel line to line

 

ACL Tibial JigACL Reconstruction Tibial Beath Pin

 

Pass Graft

 

Retrieve end of 1 nylon loop via tibial tunnel with grasper / probe

- place all 4 sutures of endobutton into loop and pull up through femoral tunnel

- separate sutures

- visualise femoral tunnel with camera

- use the pulling sutures to pull graft up into femoral tunnel

- helpful to wrap about artery forcep for traction

- then use both sutures to ensure that endobutton has flipped (rock each end back and forth)

- tension other end of graft and ensure cannot flip endobutton any further

 

ACL Reconstruction Loop 1 Prolene Passing Suture

 

Uncertain if endobutton has flipped

- check with II

- cut down on lateral femoral cortex

- supplement with interference screw

 

Tension graft

 

Hold distal sutures

- flex and extend multiple times

- check to see where graft is longest (i.e. pulled into knee)

- should secure graft where it is longest, or will have to stretch to get ROM back

- debate whether best at 0 or 30o

 

Washout Joint

 

Many bone fragments in joint

- may contribute to arthrofibrosis / cyclops / chondral damage

 

Tibial fixation

 

Place beath wire and pass RCI screw anteriorly

- usually 8 or 9 mm for men and women

- the tibial bone is soft

- will usually take a 25 mm screw / up to 35 mm

- +/- supplemental post / screw / staple

 

ACL Hamstring Autograft Arthroscopy

 

Range

 

Ensure no anterior or lateral impingement of graft

- can perform careful notchplasty

 

ACL Reconstruction No Anterior Graft Impingement in Full Extension

 

2 x RCI screws

 

ACL Hamstring 2 x RCI Screws APACL Hamstring 2 x RCI Screws Lateral

 

Tunnels

 

Tibial tunnel

- as above

 

Femoral tunnel

- pass beath pin

- drill line to line for graft size

- usually 25 mm long

 

Pass graft

 

Insert screw

 

Femur

- forward thread RCI in left, reverse in right

- allow the head of the screw to always be visible (in case need to remove)

- always slightly smaller screw in femur as bone very hard

- i.e. 7 mm tunnel for 8 mm tunnel

 

Tibia

- tibial screw is 1 mm bigger i.e. 8mm for 7 mm tunnel

Lars ACL

Indications

 

Intact but lax ACL with symptomatic instability

 

ACL Old Partial Tear Taut with Anterior Draw ArthroscopyArthroscopy Lax ACL

 

Acute ACL rupture

 

Partial Tears

 

ACL Partial Torn Arthrocopy

 

Aim

 

To pass LARS graft up intact ACL / ACL remnant

- all reaming outside in to preserve ACL

- provide a LARS scaphold for the injured ACL to heal onto

 

Technique

 

Set up

- knee 90o over bolster

- II with perfect lateral of knee

- superimposed femoral condyles

- standard arthroscopy portals

- can be difficult to set up II and arthroscopy tower together

- do so before beginning operation

 

Femoral entry point

- place beath pin just medial to patella tendon

- insert into femoral insertion of ACL on LFC

- check entry on lateral

- imagine posterior femoral condyle as circle

- entry point in centre, but 60% of distance posterior

- can also look inside knee with scope to confirm insertion

- drive out lateral femur as standard

- pull pin back through femur so that guide wire passes up into femur

- distal pin now in joint

 

Lars ACL Femoral Entry PointLars ACL Femoral Entry Point 2Lars ACL Femoral Entry Point 3

 

 

Tibial entry point

- extend knee

- aim pin for standard origin of ACL

- drive through tibia

 

Lars Tibial PinLars ACL Guide Wire Clinical Photo

 

Select Lars graft

- variety of sizes

- 7 - 8 mm

- fibre numbers 80 - 120

 

Ream tibial and femoral tunnels

- line to line to graft size

- outside in to preserve native ACL

 

Lars Femoral ReamerLars ACL Tibial Ream

 

Pass graft

- measure tibial tunnel

- apply artery forcep at appropriate distance from central graft

- allows you to know when graft is pulled through enough

- the LARS has a specifice portion designed to be inside the native ACL

- pass from the tibia up through the knee into the femur

 

Lars ACL Pass Graft 1Lars ACL Pass Graft 2Lars ACL Pass Graft 3

 

Secure

- insert femoral screw outside in

- tension tibial side

- must not overtension as there is no give in the graft

- secure tibial side with screw

 

Lars ACL Post op Xray APLars ACL Post Op Xray Lateral

 

 

 

MacIntosh Procedure

Technique

 

Incision

- lateral border femur

- 15 cm proximal to knee joint

- curve anteriorly across patella tendon

 

Harvest ITB

- expose ITB

- width and length depend on patient size

- usually central 3 cm

- take 25 - 30 cm in length

- tubularise end and leave threads long to pass tendon

 

Lateral dissection

- expose and elevate LCL

- 2cm subperiosteal tunnel above and posterior to this

- pass tendon deep to LCL and through subperiosteal tunnel

- pass inferiorly through intermuscular septum

 

Posterolateral incision

- anterior to lateral head of gastrocnemius

- allows tendon to be passed around femoral condyle

 

Medial parapatella incision

- open joint

- make drill hole from anteromedial tibia to posterior to tibial spine

- this prevents anterior impingement

- make appropriate width for tendon

- do so under direct vision

 

Pass graft

- pass curved instrument through knee and out lateral incision

- retrieve graft into knee

- retrieve through tibial tunnel

- tension

- suture graft at LCL

- pass graft under patella tendon and suture to origin

 

 

 

 

 

Over the Top Fixation

Indications

 

Back wall blow out

 

Technique

 

Lateral incision

- divide ITB at posterior aspect of femoral condyle

 

Over the top ACL Fixation 1Over the top ACL Fixation 2Over the top ACL Fixation 3

 

Pass curved hemostat

- from inside knee via medial arthrotomy

- pass around femoral condyle

- pass suture, retrieve graft

 

Over the top ACL Fixation 4Over the top ACL Fixation 5Over the top ACL Fixation 6

 

Need to make second incision in ITB

- pass graft anteriorly

- so can staple to femur

 

Over the top ACL Fixation 7Over the top ACL Fixation 8

 

 

 

 

 

E Rehabiliation

Concept Accelerated Rehabilitation

 

Shelbourne 1995

- noticed patients noncompliant with their rehab protocol were doing much better

- looked at what noncompliant patients were doing

- what they were doing was advancing activities as tolerated

 

Reviewed results of accelerated rehabilitation

- fewer ruptures with better ROM

 

Major recommendations

 

1.  Previously patients splinted in flex often in POP

- now splint in extension

- aggressive early ROM concentrating on regaining extension

 

2.  Previously prolonged NWB

- now FWB immediately with crutches

 

3.  No acute operations

- only after rehab & out of inflammatory phase

- decrease in MUA rate 10% to 0.5% 

- decrease in scar resections 19% to 1%

 

Key Points of Accelerated Program

 

1.  Post op ROM +++

- including prone hyper-extension

 

2.  Early FWB once quadriceps control 

- PWB on crutches till then

 

3.  Early functional activity

- regain full ROM

- muscle strengthening +++

- swim / cycle 3/12

- straight line jog 4/12

 

4. Gradual return to sport 

- training 5/12

- contact sport 6/12 - 9/12 - 12/12

 

Shelbourne 4 Stages

 

1.  Pre-Operative

 

Aim

- Regain full ROM

 

Mechanism

- resolve swelling

- normal gait

 

2. Acute Phase 0-2 weeks post operative

 

Aim

- obtain full ROM

 

Mechanism

 

A.  Obtain full hyperextension 

- wall slides, heel slides, prone hyperextension

 

B.  Achieve 100° flex

- decrease swelling

 

Start next phase when full hyperextension with minimal swelling and good leg control

 

3.  Recovery Phase 3 - 6 weeks

 

Aim

- resume normal gait and range

- obtain full flexion

 

Mechanisms

- co-contractions / closed chain exercises

- increased knee bends, step-ups, calf raises, leg press, stairmaster, cycle

- begin sport specific activities

 

Ends when ROM +5°-135° & resumed normal activities

 

4. Functional Phase > 6 weeks 

 

Aim

- return to sport

 

Mechanisms

- closed kinetic chain strengthening 

- joint compressed & stable

- less ACL stress than open chain

 

Swelling & pain

– sign that going too fast

- need rest

 

5.  Return to sport

 

Timing

 

Minimum 6 months

 

Guidelines

 

A.  No effusion

B.  Stable knee

C.  Good strength

- 80% other side for athlete

- 90% other side for non athlete

 

ACL Return to Sport Power Testing

 

Bracing

 

Reasonable to use brace for 2 years post ACL reconstruction

 

ACL Brace Donjoy Defiance

 

 

 

 

 

F Complications

General

- haemarthrosis

- DVT

- infection

 

Swollen Knee Post ACL

 

Septic Arthritis

 

Infected ACL ClinicalInfected ACL

 

Incidence

 

Extremely low

 

Prevention

 

Vertullo et al Arthroscopy 2012

- eliminated incidence of deep infection by wrapping graft in vancomycin

 

Options

- graft salvage / multiple washouts and synovectomy

- graft removal / may be some evidence that early graft removal eliminates cartilage damage

 

Risk

 

Early onset OA in young person

 

Infected ACL APInfected ACL Lateral

 

Arthrofibrosis

 

Characteristics

- knee inflamed and diffusely swollen

- usually FFD > 10o

- loss of flexion > 25o

- loss of patellar mobility

 

Primary and secondary

 

Secondary arthrofibrosis 

- associated with reconstruction of an inflamed knee (<3 weeks) and immobilisation

- delay reconstruction until inflammation settles and normal ROM and muscle strength regained

- stage meniscal repair and reconstruction if immobilisation requires to protect meniscus

 

Operative Management

 

1.  MUA

- 6 - 12 weeks post indexed procedure

 

Knee Arthroscopy Intra-articular adhesions

 

2.  Arthroscopic +/- open procedure

- medial and lateral releases of patella

- suprapatellar pouch

- fat pad adhesions

- intercondylar notch scarring

- notchplasty if necessary

- posterior capsular release off femur

 

Results

- 50% need no further procedures

 

FFD 

 

Causes

- non isometric graft placement

- anterior tibial tunnel placement

- poor isometricity

- inadequate notchplasty

- poor rehabiliation

- Cyclops lesion (nodule of ACL stump anterior to ACL graft)

 

Cyclops lesion

 

Cyclops lesion post ACL reconstructionCyclops Lesion

 

Definition

- intercondylar notch fibrous proliferation

- a nodule anterior to and associated with the tibial graft insertion site

- anterior to tibial tunnel

- 5-10% of patients

 

Clinical

- painless, palpable and audible clunk upon terminal extension

 

Preventative measures 

- posterior placement of the graft in the tibial ACL footprint

- adequate notchplasty

- meticulous debridement of ACL stump

- early restoration of full extension

 

Treatment

- arthroscopic resection of cyclops lesion

 

Graft rupture

 

Failure rate

- 10% over life of graft

- 1% per year

 

Instability

 

Incidence

- 10 - 20% post single bundle surgery

- return to sports rate 60-70%

- may be reduced in experienced surgeons

 

Definition

A.  KT 1000

- > 3 mm side to side difference with 30lb force

B.  Positive Pivot Shift / Lachman's / Anterior drawer

C.  Patient feels knee unstable

 

PF Joint

 

A.  Failure of Extensor Mechanism

- need with BPTB

- patellar fracture

- patella tendon rupture

- uncommon

- related to size of graft harvested

 

B.  PF Pain

- more common with BPTB

- also occurs with HS

 

Fracture

 

If using back up fixation such as a fracture, ensure sufficient distance from tibial tunnel

Alternatively, use a screw-post fixation

 

Revision ACL

Recurrent Instability

IncidenceRevision ACL Ruptured Graft MRI BPTB Allograft

 

Up to 8% patients with ACL reconstruction will have recurrent instability and graft failure

- increased with surgical inexperience

 

Graft can

 

1.  Be inadequate from the start

- inadequate tension

- poor tunnel placement

 

2.  Stretch 

- poor tunnel placement

- impingement

- non isometric

 

3.  Rupture

- may be trauma

- may be surgical issues

 

Causes Rupture

 

A. Technical Failure

 

Non anatomic tunnel placement

Inadequate notchplasty

Improper tensioning

Graft impingement

Failure graft fixation

Insufficient graft material 

 

B.  Biological Failure

 

Failed ligamentisation

Infection

 

C.  Failures due to trauma

 

Early (before graft incorporation)

Late (after incorporation)

 

Graft rupture best seen on T1

 

ACL Graft Rupture Coronal MRIACL Graft Rupture MRI SagittalRuptured ACL Graft MRI T1

 

D.  Failures due to laxity of secondary restraints

 

Rotatory instability / Varus / Valgus instability

- posterolateral corner / PCL

Skeletal malalignment

 
Technical Issues

 

A.  Non anatomic Tunnel Placement

 

Most common

- 70 - 80% Technical Failures

 

Mal-positioned grafts incur excessive tension

- impinge and become lax

 

Femoral Tunnel

 

Most common error in ACL Reconstruction

- errors in femoral placement are less forgiving

- either get a loss of motion or graft failure

 

Optimal placement

- lateral radiograph 

- intersection of Blumensaat's line and

- line extended from the posterior femoral cortex

 

ACL Graft Rupture Anterior Femoral TunnelACL Graft Rupture Femoral Tunnel Anterior

 

A.  Anterior femoral placement 

- increases tension in flexion / loss of flexion

- stretching of the graft required to obtain flexion

 

B.  Posterior femoral placement

- increases tension in extension

- need to stretch to obtain extension

 

C.  Superior femoral placement

- 12 o'clock position

- AP stability

- rotationally unstable / continue to pivot shift

 

ACL Graft Failure Vertical TunnelsACL Graft Rupture Graft Too VerticalACL Failure Graft Too Vertical

 

Tibial Tunnel

 

More forgiving

 

Ideal Tibial tunnel placement 

- posterior and parallel to the tibial intersection of Blumensaat's line in full extension

- this will prevent it impinging on the notch

 

A.  Anterior placement 

- increases tension in flexion

- may result in notch impingement in extension

- stretching of graft

 

B.  Posterior placement 

- causes PCL impingement 

- reduces the graft's ability to control AP translation

 

ACL Tibial Tunnel PosteriorFailed ACL Posterior Tibial Tunnel

 

C.  Lateral placement 

- causes impingement on the medial wall of the lateral femoral condyle

 

B.  Inadequate notchplasty

 

Graft is often larger than native ACL

- especially with BPTB

- need to assess

- debride anterior lateral part of notch and roof

 

Impingement

- loss of extension

- formation Cyclops lesion

 

ACL Graft Cyclops Lesion

 

C.  Improper Tensioning

 

Under tensioning 

- non-functioning graft

 

Over tensioning

- constrain the knee

- affect graft incorporation

 

The ideal tension is unknown

- tension BPTB graft to 5-10 lb at 10-15 degrees flexion

- tension hamstring graft to 10-15 lb at 20-30 degrees of flexion

- cyclically preload & maintain tension until secured

 

D.  Graft Fixation Failure

 

Takes 6-12 weeks for graft incorporation to occur with hamstrings

 

Graft fixation needs to be strong for this period

 

E.  Tunnel Lysis

 

Revision ACL Tibial Tunnel LysisFailed ACL Tibial Tunnel Lysis

 

Very common, cause unknown

 

No evidence that contributes to instability

Important in revision setting

 

Cause

- more common tibial side than femur

- tends to stop after 3/12

- postulated to be from synovial fluid pistoning

- hence fluid finds it easier to come down tibial tunnel as screw placed outside in

- also seen more on femoral side with endobutton (windscreen wiper effect)

 

Revision ACL Cases

Case 1

 

Revision ACL Pre AP XrayRevision ACL Pre Xray Lateral

 

Patient with traumatic failure ACL, previous hamstring with endobutton and bioabsorbable screw

Graft likely too vertical, evidence of tibial tunnel lysis

 

Revision ACL Pre MRI CoronalRevision ACL Pre MRI SagittalRevision ACL MRI Pre Sagittal 2

 

Coronal MRI can see ACL stump remnant, graft not intact.  First sagittal confirms tunnel lysis. 

Second demonstrates that femoral tunnel is sufficiently posterior

 

Revision ACL Post op APRevision ACL Post op Lateral

 

Achilles allograft used, and 12 mm x 20 mm bone plug used in femoral side.  Both tunnels drilled where indicated. 

Tibial screw ignored, old femoral tunnel ignored.  12 mm tunnels drilled. 

Old staple had to be removed.  Graft passed and fixed on femoral side with 9 x 25 mm screw. 

Achilles tendon fixed on tibial side with 9 x 25 screw

Tibial bone very poor and screw little bite (advanced very easily too far into tibia, but not seen in joint). 

New staple used, but had to be repositioned as cortical bone soft and fracture easily.

 

Case 2

 

Traumatic rupture, previous BTPT allograft fixed with metal screw in femur and 2 staples over trough in tibia

 

Revision ACL 2 MRI Revision ACL 2 MRI 2

 

MRI demonstrates graft torn, femoral tunnel too far anterior from posterior wall

 

Revision ACL 2 APRevision ACL 2 Lateral

 

Post op Xrays.  Can see that femoral tunnel too anterior.  New femoral tunnel drilled behind the old screw. 

Old tibial tunnel used.  New BPTB allograft passed and secured with bioabsorbably femoral screw and trough / staples in tibia

 

Case 3

 

Failed ACL with tibial tunnel too posterior and with lysis

 

Failed ACL Posterior tibial tunnelFailed ACL Tibial Lysis

 

Tunnels debrided / redrilled and synthetic bone plugs inserted

 

Femoral Tunnel DebridedFemoral Tunnel Bone SubstituteFemoral Tunnel Bone Graft

 

Tibial Tunnel DebridedBone Graft SubstituteTibial Tunnel Bone substitute

 

Case 4

 

Patient previous failed hamstring ACL likely from posterior tibial tunnel.  Revision ACL with contralateral hamstring with new tunnel drilled anterior in tibia.   Tibial tunnel now too anterior and revison also failed.

 

Revison ACL 4 AP XrayRevision ACL 4 Lateral Xray

 

Revision ACL 4 Sagittal CTRevision ACL CT Sagittal 2

 

Case 5

 

ACL 8 years ago, traumatic rupture.  Femoral tunnel too vertical from transtibial drilling.  New femoral tunnel at 10 o'clock position completely separate from old tunnel by using anteromedial portal.  Tibial tunnel exits at same point, but entrance more medial on tibia and guide set at 65o to ensure different tunnel.  Tibialis posterior allograft used - 10 mm in diameter over endobutton.

 

Revision ACL Vertical Femoral TunnelRevision ACL LateralRevision ACL Failed Graft

 

Revision ACL Old Femoral TunnelRevision ACL Old Tibial TunnelRevision ACL New Graft

 

 

 

 

Revison ACL Surgery

Graft selection

 

A.  Synthetic Grafts

 

Good initial results but unacceptably high failure rate with longer follow-up

 

Problems

 

1.   Too stiff (low ultimate strain) 

- poor resistance to abrasion

- ligament failure by attrition most common

 

2.  Recurrent synovitis, infection, loosening and osteolysis

 

B.  Autograft

 

1.  Contralateral BPTB / hamstring

2.  Reharvested central BPTB 

 

C.  Allograft

- many advantages (shorter surgery, decreased morbidity, larger bone blocks)

- disadvantages (disease risk, slower incorporation, higher cost)

- irradiation has dose dependent effect on mechanical properties with significant effect at 3 Mrads

- higher failure rates

 

Pre-operative Assessment

 

Crucial to good outcome

 

Patient expectations

- results not as good as primary

- aim for ADL's, sports may not be possible

 

History

- history infection

- history arthrofibrosis

- has knee ever been good or always unstable

- was it good then traumatic injury

 

Examination

 

Alignment

 

ROM

- patient hyperextension linked to poor outcomes

 

Confirm ACL deficient

- Lachman's / Anterior drawer / Pivot Shift

 

Check Secondary restraints

- assess PCL / PLC

- dial test important

- may need posterior and varus stress xrays

 

Old OT notes

 

Technique / graft

Fixation techniques

Tunnel sizes

 

Xray

 

AP and Lateral

- assess tunnel placement

- Assess metal work

- types of fixation

- metal v plastic

 

Revision ACL Lax Graft Anterior Femoral Tunnel

 

Stress xrays

- check PCL / PCL

 

MRI

 

1.  Is graft intact / non functional or ruptured

 

Revision ACL Intact but Lax GraftRevision ACL Graft Rupture

 

2.  Assess meniscus / chondral surfaces

 

3.  Evidence of other ligament injury (difficult)

 

CT

 

Assess for tunnel lysis

 

Arthroscopy / EUA

 

Confirm graft lax or torn / + Pivot Shift

 

Revision ACL Lax BPTB Graft

 

4 Tunnel Situations in Revision Surgery

 

1.  Correct tunnel position, normal size

 

Reuse same tunnels

- remove hardware

- may require larger screws if some lysis

 

2.  Correct tunnel position, increased size secondary to lysis

 

Tibial and femoral tunnel Lysis

 

Staged bone grafting of tunnels

- use bone cores from iliac crest

- premade synthetic bone graft plugs

- wait for union / 3 - 6 months

- ACL revision

 

BTPB / Achilles allograft with larger bone block

 

3.  Slightly incorrect tunnel position

 

Staged bone grafting of tunnels

 

4.  Very incorrect tunnels

 

New tunnels anterior or posterior

- can leave old metalwork intact

 

Revision ACL Graft Placed posterior to old femoral tunnelRevision ACL New Posterior Femoral Tunnel

 

Surgery

 

Issues

 

1.  Skin incisions

 

2.  Hardware removal

- screwdrivers for metal RCI screws

- drill through bioabsorbable screws

- ignore endobutton

- careful removal of all material in tunnels

 

3.  Revision Notchplasty

- roof and lateral wall

- often osteophytes in this area

- must leave sufficient bone stock

 

4.  Bony tunnels

 

Find femoral tunnel

- pass beath pin

- decide if tunnel reusable

- will usually be larger

- can use screw if posterior wall remains

 

Usually do tibial tunnel last

- will lose vision as water escapes

- can be difficult to find tunnel

- use needle to find tunnel

 

5.  Graft

 

BPTB good option

- larger bone blocks useful in enlarged tunnel

 

Contralateral hamstring

- involve normal knee

- fixation difficult

 

6.  Fixation

 

Femoral

- screw if posterior wall remains

- otherwise endobutton

- can tie over screw on femur if need to 

 

Tibia

- usually scew +/- post

 

6.  Secondary restraints

 

A.  Posteromedial instability

- reconstruction / advancement

 

B.  Posterolateral

- valgising HTO

- reconstruction

 

 

 

AVN SONK

 

SONK              vs                          Atraumatic AVN

 

>55                                              Often mid 30's

MFC                                              Multiple areas

99% unilateral                               80% bilateral

Knee only                                      60-90% other joint

Juxta-articular                                Epiphysis / diaphysis / metaphysis

 

Primary Spontaneous Osteonecrosis Knee (SONK)

 

Clinical

 

Usually healthy woman age 60+ years

- sudden onset of severe knee pain with normal Xray

 

Site

 

Almost always MFC (SONK is a MONK)

- there are case reports of LFC SONK

 

99% unilateral

 

Exquisite local tenderness

- may be effusion

 

SONK of tibial plateau less common 

 

Aetiology

 

Yamamoto et al JBJS Am 200

- histological study

- evidence of microtrauma / insufficiency fracture

- initial event

- postulated that osteonecrosis is then secondary event around lesion

 

Primary vascular osteonecrosis may be much more rare

 

X-ray

 

Initially normal

 

Later develop

- subchondral lucent line / crescent Sign

- flattening of condyle

- patchy sclerosis

- can have rapid collapse into varus with development degenerative changes

 

Spontaneous Osteonecrosis of the Knee

 

Bone Scan

 

Normal x-ray & painful knee in 60 year old think AVN

- consider bone scan

- probably superceded by MRI

 

Findings

- focal increase in uptake on one side of joint 

- if tibia and femur more likely OA

 

MRI

 

May be normal in early stages

 

TI

-  low signal areas in subchondral region 

 

SONK MRI Sagittal

 

T2

- low signal

- surrounding high intensity signal secondary to oedema

 

MRI SONK T1

 

Staging Insall

 

Stage 1 

- normal x-ray with positive bone scan / MRI

 

Stage 2 

- subtle flattening of weight bearing portion of condyle

 

Stage 3 

- typical lesion

- radiolucent area with sclerotic halo

 

Stage 4 

- halo thickened with subchondral collapse

 

SONK Xray Stage 4

 

Stage 5 

- degenerative change

- varus or valgus angulation

 

 

Arthroscopic findings

 

Localised area of flattened cartilage

- discoloured

- eventually demarcates

- develop flap of cartilage over necrotic bone

 

The articular sequestrum becomes partially separated as hinged flap

- may separate completely

- cartilage defect becomes filled with necrotic debris and fibrocartilage

- develop OA

 

Management

 

Non Operative Management

 

NHx

 

Many will resolve spontaneously

- especially small lesions

- best prognosis if chondral surface intact

 

Yates et al Knee 2007

- followed up 20 patients diagnosed on MRI

- average resolution of symptoms and lesion over 6 months

 

Program

 

Decrease impact exercises

Consider unloading brace

Analgesia / NSAID's

Consider bisphosphonates

Follow for 6 - 12 months with repeated MRI looking for resolution / progression

 

Operative Management

 

Intact chondral surface / Stage 1 lesion

 

Decompression / Percutaneous Drilling

 

Indication

- failure non operative treatment > 6/12

 

Forst et al Arch Orthop Trauma Surg 1998

- 16 patients with average age 60

- percutaneous drilling with 3 mm drill

- instant resolution of pain

- cannot prevent progression of disease if chondral flattening present

 

Chondral Defect

 

Microfracture

 

Akgun et al Arthroscopy 2005

- debridement of chondral defect and microfracture

- 26 patients average age 48

- 71% could participate in strenous exercise with minimal exertion

- in the remainder the ON progressed on MRI

 

HTO

 

Technique

- unload MFC

- younger high demand patient

- combine with microfracture / osteochondral grafting

 

Osteochondral grafting

 

Tanaka et al Knee 2009

- 6 patients average age 50

- stage III and IV

- good results in knee scores at 2 years

 

UKA

 

Good option as disease is unicompartmental

 

Langdown et al Acta Orthop 2005

- 29 knees treated with Oxford UKA

- good outcomes and no implant failures at average 5 years

 

TKR

 

Secondary osteonecrosis

 

Knee AVN 1Knee AVN 2

 

Causes

- Steroid Therapy (90%)

- Alcohol

- SLE

- Sickle Cell Disease

- Diver's / Caisson's

- marrow proliferative disorder

- chemotherapy

 

Clinical

 

Gradual onset of pain

- lateral condyle in 60%

- younger patients, mid 30's

 

Site

 

Bilateral in 50%

- 70% have other joints involved

 

MRI

 

More extensive involvement through knee

 

Operative Options

 

Indications

- failure non operative treatment

- continued pain

 

Percutaneous Drilling / Decompression

 

Marulanda et al JBJS Br 2006

- percutaneous drilling in 61 knees with secondary ON

- successfull in all 24 knees with small lesions

- successful in 32/37 (86%) knees with large lesions

 

 

 

 


 

Arthrodesis

Issues

 

Like elbow arthrodesis, knee arthrodesis is an option of last resort

 

Example

- cannot sit on airplane toilet with door closed

 

Aims

 

Coapt 2 coplanar cancellous surfaces under compression with rigid fixation

 

Indications

 

Septic arthritis

Salvage failed TKR / infected TKR

Tumour

Charcot Join

PFFD

 

Contraindications

 

Bilateral knee fusion

Ipsilateral hip fusion

 

Problems

 

Fusion rates

- can be difficult to obtain fusion

 

Difficulties mobilising

- give patient trial in cylinder cast

 

Position

 

Short leg

- fuse straight 

 

Normal length

- in 10° for swing through

 

Valgus 5 - 7o

 

External rotation 5 - 10o

 

Options

 

1.  External fixator

2.  IMN

3.  Double plating

 

Results

 

Mabry et al Clin Orthop Related Research 2007

- arthrodesis for infected TKR

- union in 41 / 61 patients treated with external fixation, deep infection rate 4.9%

- union in 23/24 patients treated with IMN, deep infection rate 8.9%

 

1.  External Fixation

 

Knee Fusion External Fixation

 

Advantage

- simpler

- less blood loss

- better in infection

 

Disadvantage

- pin tract infection, loosening

 

Technique

 

Anterior longitudinal incision

- medial parapatellar arthrotomy

- patella excised

 

Bony cuts 

- use TKR jigs 

- aim to resect only 1-2 mm

- cut tibia at 90° 

- cut femur 10° flexion or 0° if short / 7° valgus / 5° ER

 

Bilateral & Biplanar external fixator

 

First construct bilateral frame in coronal plane

- 3 femoral & 3 tibial transfixion pins from medial to lateral

- bar on each side

 

Then add unilateral frame in sagittal plane

- 2 femoral & 2 tibial 1/2 pins anteriorly

- anterior bar

 

Circular frame

 

Advantage

- allows compression and weight bearing

- post operative alignment adjustment

 

Bone graft

 

If less than 50% apposition

- may use patella

 

Fixation remains for 12/52

 

2.  IMN

 

Options

 

A.  Long fusion nail S & N / Stryker

B.  Wichita nail / Stryker / Modular nail

 

Pre-operative assessment

 

Full-length AP & Lat XR with magnification marker

- determine length & diameter of nail

 

1.  Long fusion nail

 

Disadvantage

- different IM canal size between tibia and femur

 

Radio-lucent table

- drape to pelvis

- sand bag under hip

 

Medial parapatella approach to knee

- bone cut made

 

Guide wire passed down tibia

- reamed until cortical bone encountered

 

Trochanteric fossa exposed routinely

- guide wire passed & femur reamed

- ream to size determined in tibia

 

Insert nail antegrade from GT across knee to distal tibia

- nail should bend concave laterally to recreate anatomical alignment & slight flex

 

Should not end in diaphyseal portion of either bone 

- risk of stress fracture

 

Lock nail distally but not proximally

- proximally if rotationally unstable

 

2.  Wichita nail / Modular nails

 

Concept

- tibial and femoral components insert via knee & then join together

- different sizes for femur and tibia

- single knee incision

 

Problem

- very difficult to remove after fusion

 

 

 

 

Chondral Defects

Chondral Defect Medial Femoral CondyleKnee OCD Arthroscopy Type 4

 

Mosaicplasty

 

Anatomy / Biochemistry

 

Constituents of cartilage

 

1. Type II collagen

- triple helix

- provides tensile strength and mechanical integrity

- 50% of dry weight

 

2. Proteoglycans

- 10%

- glycosaminoglycans with keratan sulphate and chondroitin sulphate

- negative charge has high affinity for water

 

3.  Water

- 65-85% of weight

- highly attracted to GAG

- resistant to compressive loads

 

4.  Chondrocytes

- 2% weight

- low oxygen, avascular environment

- anaerobic metabolism

- make collagen and GAG

 

Structure of cartilage

 

Superficial zone

- 10-20%

- arranged parallel to surface

 

Intermediate zone

- more haphazard

 

Deep zone

- chondrocytes in columns

- perpendicular

 

Calcified Zone / tidemark

- above subchondral bone

- any mitotic ability of chondrocytes ceases when this develops

 

Pathology

 

Inability to heal

- avascular

- nil pluripotent cells in maturity

- nil mitotic ability

- limited synthetic ability in adult

 

Some ingrowth from sides can occur

- healing size dependant

- 3 mm lesion will heal

- 9 mm will not

 

Damage

- loss of cartilage results in loss of water and increased stiffness in remainder

- vicious cycle of continued damage

- nil ability to heal unless penetrates thick subchondral bone

- allows bleeding and primitive mesenchymal cells

- typically produce fibrocartilage

 

MRI

 

Chondral Defect Full Thickness

 

Classification

 

Outerbridge

 

Grade 1: Softening and swelling of the cartilage

Grade 2: Fragmentation and fissuring in an area half an inch or less in diameter

Grade 3: Same as grade 2 but an area more than half an inch in diameter is involved

Grade 4: Erosion of cartilage done to bone

 

Issue

- difference between grade 2 and 3 is size

- depth is probably more of an issue

 

ICRS / International Cartilage Research Society

 

Grade 0: Normal

 

Normal Hyaline Cartilage

 

Grade 1: Nearly normal / soft indentation and/or superficial fissures and cracks

 

Grade 1 Cartilage LesionGrade 1 Chondral Lesion Femur

 

Grade 2: Abnormal (lesions extending down to < 50% of cartilage depth)

 

Grade 2 Chondral Lesion

 

Grade 3:  Severely abnormal (cartilage defects > 50% of cartilage depth)

 

MFC Grade 4 LesionICRS Grade 3 Chondral Lesion

 

Grade 4: Severely abnormal (through to the subchondral bone)

 

Grade 3 Chondral InjuryICRS Grade 4 Chondral Lesion

 

Sizing

 

5mm graduated probe

- tend to overestimate size arthroscopically

 

Measure in 2 dimensions

- give a size in cm2

- assumes that lesions are basically rectangular

 

Chondral Lesion 5 mmChondral Width Measurement

 

Treatment Algorithms

 

Indications

- grade 3 or 4 ICRS lesions

 

Niemeyer et al Arthroscopy 2011

- lesions < 4cm2 microfracture

- lesions > 4cm2 or failed microfracture ACI

 

Cole et al JBJS 2009

- < 2 - 3 cm2 with microfracture or OATS (osteochondral allograft transplantation)

- > 2 - 3 cm2 with osteochondral allograft (OCA) or autologous chondrocyte implantation (ACI)

- trochlea - microfracture or ACI + anteromedialization of the trochlea

 

Brittberg 2003

- osteochondral lesions < 8mm deep can be managed with ACI

- osteochondral lesions > 8mm deep require bone graft / ACI or OATS

 

1.  Microfracture / drilling

 

Microfracture Chondral Defect InitiallyMicrofracture Post PreparationMicrofracture Awl Holes

 

Principle

- pluripotent marrow cells

- produce fibrocartilage to varying degree

- principally type 1 cartilage

- low stiffness and poor wear characteristics over time

- may be more beneficial to combine with realignment procedure

 

Indications

- young patient

- contained defect

- best results < 2 cm2

- BMI < 30

- age < 40

- need cartilage on each side to contain clot

 

CI

- axial malalignment

- uncontained lesion (edge of condyles / intercondylar notch

 

Chondral Defet Uncontained

 

Technique (Steadman J Knee Surg 2002)

 

1.  Debride all unstable cartilage to stable edge

- removed calcified cartilage layer with curette, protect subchondral bone

- create a perpendicular edge which helps to hold the superclot

- if there is a great deal of subchondral sclerosis may remove with arthroscopic burr

- until reveal punctate bleeding

 

Microfracture Currette BaseMicrofracture Arthroscopic Awl

 

2.  Arthroscopic awl

- usually have bend of 30o (Steadman Pick)

- typically 3-4 mm apart

- depth until see fat globules (2-3 mm)

- start at periphery and finish at centre

- will see blood oozing if drop pump pressure / turn off tourniquet / apply suction

 

Microfracture Awl Holes Pre SuctionMicrofracture Awl Holes Bleeding

 

Post op

 

NWB 8/52

Full passive ROM

Brace locked 0 - 20o for PFJ

ROM brace to prevent varus / valgus

No running for 3/12

No sports for 6/12

 

Complications

 

Patients may feel catching of perpendicular edge

- will resolve over time

 

Swelling common for 6-8 weeks

 

Results

 

Knutsen et al JBJS Am 2007

- prospective RCT ACI v microfracture

- 77% good results in both groups at 5 years

 

Steadman et al Am J Sports Med 2004

- combined microfracture and HTO in patients with varus > 5o

- effective at reducing pain and improving function

 

2.  Membranous Autologous Cartilage Implantation

 

MACI

 

Principle

 

Transplant living viable cells

- capable of synthesising and maintaining a cartilaginous matrix

- makes a substance physically and histologically similar to hyaline cartilage

 

MACI v ACI

- cells presented on a membrane for implant

- ACI have to harvest periosteum to secure cells in place

 

Requirements

 

Nil instability

Nil malalignment

 

Problem

 

Doesn't deal with bony defect

- only cartilage defect

 

Technique Harvest

 

Harvest mature chondrocytes

 

Biopsy taken from NWB area

- in notch or lateral edge of femoral cartilage

- use small punch, take 5 - 6 very small bites

 

Placed in tubes of saline for transport

- provided by company

- blood taken to isolate serum

- cells isolated and washed

- expanded in cell culture

- attached to membrane

- process takes about six weeks

 

Technique Implantation

 

Approach

- medial or lateral parapatellar

- if lateral lesion very large, may need medial parapatellar approach to evert patella

- cut through retinaculum in extension so can pull up tissue towards knife and avoid cutting femoral condyle

- distally often have to make small radial incision in meniscus which can be repaired afterwards

- again, take care to protect the tibial plateau cartilage

 

Lesion

- use knife to cut cartilage edge to sharp stable margin

- use curette at base, but must keep subchondral plate intact to prevent bleeding

- excess bleeding will wash away graft

- options to control bleeding involve the use of adrenalin soaked gauze or fibrin glue

 

Sizing

- use foil from suture pack and cut to size

- want graft to be undersized rather than oversized

- needs to fit into defect and not overlap edges

- in this way it will be stable and not be torn away with ROM

- place onto membrane

- must ensure that the cartilage cell side (which look rough) will be placed down

 

Insertion

- run fibrin glue from above down

- will set quickly

- take graft off paper and insert

- finger digital pressure whilst glue sets

- reassess MACI and check edges are not overhanging

- trim with scissors if needed

- ensure is stuck down (can reapply glue and re-pressurise)

 

ROM

- do a rough aggressive ROM to ensure is graft stable 

 

Post op

 

NWB 8/52

- limit ROM to 90o for 6 weeks

- no sports minimum 6 months

 

Results

 

Ebert et al Am J Sports Med 2011

- 5 year clinical and MRI follow up of 41 patients

- 90% good or excellent filling of chondral defect on MRI

- 86% able to do ADL's

- 76% able to return to sport

 

3.  Autologous Chondrocyte Implantation

 

ACI

 

Implantation

 

1.  Harvest a periosteal graft form proximal medial tibia

- medial or lateral parapatellar approach

- nothing done to subchondral plate to prevent any bleeding

- place periosteum cambium layer down

- suture in place with 6.0 Dexon / Vicryl

- seal edges with fibrin glue except with one corner

- inject cells, seal edge with fibrin glue

 

2.  Porcine collagen ACI-C

 

Results

 

Bartlett et al JBJS Br 2005

- RCT of ACI-C v MACI

- arthroscopic review at one year

- 80% good cartilage in ACI v 66% in MACI

- similar clinical outcomes in each

 

4.  Mosaicplasty / Osteochondral Autograft Transplant / Osteochondral Allograft Transplantation (OATS)

 

Pre MosaicplastyChondral Defect Post MosaicplastyOsteochondral Allograft

 

Chondral DefectDefect debridedHarvestMosaicplasty

 

Principle

 

Take bone plugs on bone and cartilage

- implant in defect

- get coverage with normal hyline cartilage

- also deals with bone defect

 

Technique

 

Prepare Defect

- debride all tissue from defect

- create cylindrical holes with drill

 

Donor sites

- periphery of femoral trochlea

- trochlea notch

- plug size 4.5 mm usually

 

Implant

- fill with plugs of bone and cartilage in mosaic fashion

- fill 60 - 80%

- slightly recess cartilage on plugs

- attempt to match radius of curvature

 

Post op

 

MRI at six months

- assess cartilage regrowth

 

Mosaicplasty MRI Post Implantation Good Cartilage CoverMosaicplasty MRI Post Implantation Sagittal Good Cartilage Cover

 

Results

 

Hangody et al Am J Sports Med 2010

- 354 patients followed up for average 9 years

- 91% good results in femur

- 86% good results in tibia

- 74% good results in PFJ

- 92& good results in talus

 

Gudas et al Arthroscopy 2005

- RCT of OATS v microfracture of 60 young adults

- all with chondral defects, followed up for 3 years

- 93% OATS and 50% microfracture returned to sport

 

5.  Osteochondral allografts

 

Osteochondral Allograft PreOsteochondral Allograft PostOsteochondral Allograft

 

Advantage

 

Very large, non contained defects

Restore anatomic contour

Nil donor site morbidity

 

Viable chondrocytes

 

Fresh grafts

- 70% viable

- None on frozen, irradiated grafts

 

Technique

 

CT

- match curvature of radius of donor

 

Combine with HTO if any malalignment

- usually HTO for medial femoral condyle defects / in varus

- usually distal femoral osteotomy for valgus deformity

 

Press fit

- if surrounding by good bone

 

Cases

 

Case 1 

 

Osteochondral Allograft PrePost Osteochondral Allograft

 

Case 2

 

Failed OCD APOCD Failed Fixation Lateral

 

Osteochondral Allograft and HTO APOsteochondral Allograft HTO Lateral

 

Case 3

 

Tibial Plateau OA APTibial Plateau OA Lateral

 

Osteochondral Allograft Tibial Plateau0001Osteochondral Allograft Tibial Plateau0001

 

Results

 

Gross et al CORR 2001

- 75 distal femoral osteochondral allografts

- patient average age 27, average follow up 10 years

- 68% had HTO or DRVO

- 20% graft failures (3 graft removals, 9 TKR)

- of the remaining cases, 40/48 patients had good or excellent outcome

 

6.  Hemicap

 

Knee Hemicap AP Post OCDKnee Hemicap Lateral

Common Peroneal Nerve Palsy / Footdrop

Incidence

 

Most common lower limb neuropathy

 

Aetiology

 

Valgus TKR - 3%

 

HTO - 10%

 

Direct Trauma / Compression

 

Knee Dislocation

 

Tibial fracture

 

Cast / Dressing

 

Lateral Meniscus Repair

 

Anatomy

 

Bound to periosteum of fibula in proximal 40mm 

- safe between 40-70 mm

- high risk 70 - 160

 

Perform osteotomy between 40-70mm from head or >160mm

 

CPN

- L4,5 S1,2

- runs along biceps femoris (supplies short head)

- over lateral head gastrocnemius

- penetrates posterior intermuscular septum

- adherent to periosteum of fibular neck

- divides into superficial and deep peroneal nerves

 

SPN

- passes between PL and PB (supplies them)

- runs along lateral cortex of fibula

- runs between EDL and PLB

- pierces fascia 10-12 cm above lateral malleolus

- at some points is only 5mm from anterolateral fibula

- 6 cm above distal fibula, divides into intermediate and medial dorsal cutaneous nerves

 

DPN

- courses anteriorly around fibula neck

- runs along anterior cortex of fibular for 3-4 cm

- passes under intermuscular septum between lateral and anterior compartments

- enters the anterior compartment

- quite tethered here so is more at risk that SPN

- supplies muscles of the anterior compartment

- Tibialis anterior is first branch off DPN

- runs with anterior tibial artery between EHL and EDL (Tom Had A Night Down Town)

- passes under the extensor retinaculum

- branch to EDB, sensation to first web space

 

Clinical

 

Injury to CPN & DPN both cause foot drop

 

Injury to CPN 

- foot drop & supination deformity during swing phase 

- loss of T nnt (DF) 

- loss of peroneus longus / brevis (evertor)

 

Injury to Deep Peroneal 

- only foot drop 

- peronei supplied by SPN

 

Injury in THR

- sciatic nerve has tibial & peroneal components

- in sciatic nerve palsy usually lose one or the other

- tibial nerve supplies all hamstrings except short head biceps

 

At hip only 20% of volume of sciatic nerve is nerve fibres

- remainder is adipose tissue

- repair here often fails as unable to oppose nerve fibres

 

DDx

 

DDx CPN at fibula head vs Peroneal component of sciatic nerve at hip

- EMG of short head of biceps 

- denervation means sciatic nerve

 

DDx CPN v L5 nerve root

- abductor function lost with L5 nerve root injury

 

NHx

 

Some authors report resolution of palsy if left long enough

 

Dee  

- 30% recover

- 10% partial recovery

- 60% no recovery

 

Rose, Ranawat and Insall 1982

- 6/23 cases who had motor loss recovered completely

 

Asp and Rand

- 26 palsies 8998 TKR

- complete motor and sensory only 7/19 full recovery

 

Management

 

Non operative Management

 

Valgus TKR with immediate post-op palsy

 

Remove all constricting dressings

- flex to 30-40°

- ensure no compartment syndrome

- evacuate haematoma if present

 

Operative Management

 

1.  Neurolysis

 

A.  Krackow 1996

- patients with CPN palsy post TKR

- EMG and NCS at 3/52 / repeat at 3/12

 

Operative exploration at 4/12 if persistent dysfunction 

- release of nerve

- findings at surgery 

- epineural fibrosis

- bands of fibrous tissue constricting nerve at fibula head / proximal origin peroneus longus

- felt CPN palsy was not unlike peripheral compressions elsewhere & therefore treat as CTS

- 31 patients minimum 2 months post-op

- 97% improved post decompression 

 

Full recovery of motor function regards time from injury

- < 6/12        8/8

- 6 - 12/12    4/5

- 1-2 year      7/11

- > 2 years     6/7

 

Non operative

- only 3 of 9 treated non-op reported improvement

 

B.  Kim et al Neurosurg 2004

- neurolysis if recordable action potential

- 107/121 (88%) recovered useful function

 

2.  Nerve repair

 

Kim et al Neurosurg 2004

- 318 injuries

- 19 patients with end to end

- 16/19 good results at 2 years

 

3.  Nerve grafting

 

Siedel et al Neurosurg 2008

- 70% good results in patients with nerve in continuity (nerve stimulator)

- had external or internal neurolysis

- only 28% good functional result from sural nerve grafting

- related to graft length

- good result in 44% if graft < 6 cm (4/9)

- good result in 11% if graft > 6 cm (1/9)

 

4.  Tendon transfers

 

Tibialis posterior transfer

- passed through interosseous membrane

- sutured to T ant, EHL, EDL

 

Tibialis Posterior HarvestTibialis Posterior Transfer

 

Results

 

Ozkan et al J Reconstr Microsurg 2009

- 34/35 achieved DF to or above neutral

 

Diagnostic Dilemmas

 

1.  No anterior / lateral / posterior compartment working

 

DDx

 

A.  Compartment syndrome

- all 4 compartments

- huge compartment syndrome

 

B.  Sciatic Nerve

- no hamstrings

 

C.  Spine 

- taken out L4,5 & S1

- massive disc on MRI

 

2.  No anterior / lateral

 

DDx

 

A.  CPN knee

- normal short head biceps EMG

 

B.  CPN higher

- abnormal short head biceps EMG

 

3.  No posterior compartment

 

DDx

 

A.  Compartment syndrome

- deep and superficial posterior

 

B.  Tibial Nerve

- no hamstring function

 

C.  Spine

- S1 compression

- peroneals should be gone as well

 

4.  No Posterior / Lateral

 

DDx

 

A.  Spine

- S1 compression

 

B.  Compartment syndrome

 

5.  No Anterior

 

DDx

 

A.  Compartment syndrome

 

B.  Deep peroneal injury

 

 

 

 

High Tibial Osteotomy

Background

Aetiology Unicompartmental OAKnee Medial Compartment OA

 

Trauma

Meniscectomy

Osteonecrosis

Varus or valgus malalignment

 

Goals of Osteotomy

 

Relief of pain

Improve function

No loss of ROM

No or slight restriction of activity

Allow heavy functional demands 

 

Indications 

 

1.  Medial compartment OA + varus malalignment

- pain localised to involved compartment

- typically male < 60 with high level of activity

- flexion > 90o

- FFD < 15

- varus < 15o

- no lateral subluxation (<10 mm)

- medial bone loss < 3 mm

- ACL intact

 

2.  Osteochondritis Dissecans of MFC

 

3.  SPONK MFC

 

4.  Posterolateral instability with varus knee

- a PLC reconstruction in setting of varus knee with fail

 

5.  Chondral grafting MFC

 

Contra-Indications

 

Patient Factors

- lateral compartment OA

- PFJ compartment OA

- inflammatory arthritis

- peripheral vascular disease

- obesity > 1.32 x ideal body weight 

 

Technical Factors

- lateral subluxation of tibia >1cm

- lateral thrust

- FFD > 10-15o

- Flexion < 90o

- Varus > 15°

- Valgus knee (HTO in this setting will create oblique joint line)

 

Concept

 

HTO works well in a select group of patients

- no activity modification required compared with TKR

- results tend to deteriorate with time

- modern fixation techniques have superior results

 

Rationale

 

Assumes primary cause of unicompartmental OA is mechanical

 

Mechanical

 

Provides realignment of limb

- reduces abnormal loading stresses on damaged cartilage and bone

 

Redistributes forces to unaffected lateral compartment

 

Biological / Regenerative

 

Some evidence fibrocartilaginous proliferation in unloaded compartment

 

Options

 

Lateral Closing Wedge HTO

Medial Opening Wedge HTO

 

Lateral Closing Wedge Osteotomy

 

HTO Lateral Closing Wedge

 

Advantage

- large area cancellous bone under compression

- inherent stability

- good union rates

- early weight bearing

- quadriceps provide compression

 

Disadvantage

- patella baja (improved by early ROM with good fixation)

- more difficult to obtain desired correction / 2 osteotomies required

- must completely excise exact size wedge of bone (difficult to do)

- must disrupt proximal tibia-fibula joint (risk injury CPN)

- shortens leg

- creates LCL laxity

- decreases proximal tibial bone stock

 

Medial Opening Wedge

 

HTO Opening Wedge

 

Advantage

- easier to obtain desired correction (only single osteotomy required)

- less surgical dissection

- no proximity to CPN

- no need to mobilise proximal fibula

- tighten MCL

- maintain bone stock especially with large corrections

 

Disadvantage

- relatively unstable

- risk loss of fixation

- delayed / non union

- NWB

- require bone graft

- lengthens leg

- displaces patella / increases PFJ forces

 

Decision Making

 

Small Correction 10 - 12o

- either technique fine

- closing wedge more difficult but union rates hight

 

Large correction i.e. 20o

- opening wedge probably indicated

- otherwise sacrificing too much bone / risk patella baja / subsequent TKR very difficult

 

Results 

 

Outcomes

 

Coventry et al JBJS Am 1993

- 87 knees with varus OA

- age 63 (41-79)

- 2/3 male, 1/3 female

- 87% survival at 5 years, 66% at 10 years

- poor outcome with relative weight > 1.32 ideal

- best outcome with valgus angle > 8o

- 94% survival at 5 and 10 years

 

Naudie et al CORR 1999

- minimum 10 year follow up 106 HTO

- 70% survival at 5 years, 50% survival at 10 years, 40% 15 and 30% 20 years

- age > 50, lateral tibial thrust, preoperative knee flexion < 120 and insufficient correction associated early failure

- patients younger than 50 with flexion > 120o had 95% 5 year and 80% 10 year survival

 

OW v CW HTO

 

Brouwer et al JBJS Am 2007

- RCT of OW v CW aiming for 40 overcorrection

- achieved 3.4o average in CW and 1.3o in OW

- concluded OW had more accurate correction, but no clinical difference

 

Smith et al Knee 2010

- meta-analysis

- no difference in infection / DVT / non union / CPN palsy or revision to TKR

- opening wedge had increased posterior slope and increased angle correction

- opening wedge also had higher incidence patella baja

Complications

Undercorrection /  loss of correction 

 

Most important factor in good results and duration of results

- must correct to 8o of valgus

- mechanical axis must pass through lateral joint line

 

HTO Insufficient Correction

 

Causes

- inadequate initial correction

- loss of correction (failure fixation, failure bone grafts, non union)

 

CPN Palsy 

 

Common 2-3%

- pressure from cast or 

- direct injury during operation (closing wedge)

- anterior compartment syndrome (opening wedge)

 

Fracture

 

A.  Intra-articular

 

HTO Closing Wedge Intra-articular fracture

 

Occur in opening or closing wedge

 

Causes

- proximal fragment too small

- osteotomy too incomplete / trying to preserve far cortex for stability

 

Prevention

- proximal fragment minimum 15 mm thick

- osteotomy within 10 mm of far cortex

- drill holes in far cortex

- slow correction to allow stress relaxation

 

B.  Unstable Osteotomy / Fracture Far Cortex

 

HTO Closing Wedge Medial FractureHTO Closing Wedge Medial Fracture Callous

 

Avoid

- don't penetrate medial lateral side

- slow correction

- after plastic deformity / not fracture

 

Instability

- place a Richards staple / plate over fracture site

 

Compartment syndrome

 

Unknown incidence

 

Avoid by

- reduced by using drain

- don't close compartment

- avoid regional blocks

- monitor closely

 

Infection 

 

Can complicate future TKR

- difficult to manage

- essentially have infected fracture

- principles of control infection / maintain stability / obtain healing

 

DVT/PE

 

Up to 40% rate of DVT

- reports of fatal PE

- need to use prophylaxis

 

Non union

 

Problematic in opening wedge

- smoker

- diabetic

- large corrections

 

<1% incidence in closing wedge above tibial tuberosity

 

Patella baja

 

Closing wedge

- caused by immobilisation and contracture

- eradicated by rigid internal fixation and aggressive early ROM

 

Problems

- anterior knee pain

- subsequent TKR difficult

 

Also seen in anterior wedge

 

 

Conversion HTO to TKR

Approach

 

1.  Incision and skin flaps

- previous incision may be L shaped

- may be good to use a vertical midline incision initially in HTO

- can usually incorporate incision

 

2.  Removal of hardware

- may wish to consider staged procedure

- staples not usually a problem (can ignore)

 

TKR HTO APTKR HTO Lateral

 

3.  Patella Baja

 

Problem

- patella eversion and exposure difficulties

- PT at risk for avulsion

- may need to consider quadriceps snip / osteotomy

 

HTO to TKR Lateral Preop BajaHTO to TKR Lateral

 

Bone Cuts

 

1.  Decreased tibial bone stock

 

Lateral closing wedge

- loss of lateral bone stock

- may rarely need augments

 

HTO to TKR Preop APHTO to TKR Post op AP

 

2.  Anterior tibial slope

 

Due to incomplete posterior osteotomy closure

- need to be aware

- ensure correct slope with bone cuts

 

3.  Offset tibial shaft medially 

 

Seen with closing wedge

- need offset stem to avoid lateral overhang

- more common when large corrections have occurred

- have revision stems available

 

HTO to TKR Post op AP 2

 

Soft tissue Balancing

 

Valgus knee alignment

- need appropriate releases

 

Soft tissue balancing

- restoring the tibial slope

- difficulty with flexion / extension balancing

- may need higher constraint

 

TKR CCK post HTO APTKR CCK post HTO Lateral

 

Results

 

Controversial

- conflicting reports

 

Meding Sept 2000 JBJS 

 

39 consecutive AGC bilaterally

- one with HTO / one without

- 8.7 year follow up

- 36 of 39 no side to side difference in pain

- 85% of post HTO no pain

 

 

 

Lateral Compartment OA

AetiologyKnee Lateral Compartment OA

 

Trauma

RA

Rickets / osteomalacia

 

Issues

 

Horizontal joint line important

- < 10° tilt acceptable

 

> 10o joint line tilt / due to femoral valgus

- continues to overload lateral compartment

- get shear forces and lateral tibial subluxation

- distal femur appears to fall off medial tibial plateau

 

Options

 

1.  Medial closing wedge HTO

 

Indications

- anatomic axis <12° valgus

- hoint line < 10°

 

2.  Distal femoral osteotomy

 

Indications

- > 12o valgus

- ? any valgus malignment requiring osteotomy

- > 90o flexion

- < 150 FFD

 

Options

- medial closing wedge

- lateral opening wedge

 

Aim 

- produce 0-2° valgus of anatomical axis

- unload the lateral compartment

 

Preoperative Planning

 

Similar to HTO

Calculate current anatomical alignment

- calculate angle of correction required

 

Valgus OA Preop PlanningValgus Knee OA Preoperative TemplateDistal Femoral Osteotomy Postop View

 

Medial Closing Wedge Osteotomy

 

Distal Femoral Osteotomy MedialDistal Femoral Osteotomy Medial Closing Wedge

 

Technique

 

Patient supine on a radiolucent table

- leg in figure 4

- mark of centre of ankle

- ECG dot and artery clips centre of femoral head

- can then check mechanical axis post correction

 

Medial Approach

- medial longitudinal incision

- dissection carried down to fascia of VMO and joint capsule

- vastus medialis lifted off medial intermuscular septum leaving cuff of tissue to protect vessels

- femoral shaft is exposed

 

Osteotomy

- resect templated wedge

- insert blade plate parallel to joint line

- close femoral wedge

- assess correction with diathermy

- if insufficient can often compress femoral shaft into distal metaphysis

 

Post-Op

- 6/52 TWB in ROM brace 

- full ROM

 

Results

 

Wang et al JBJS Am 2005

- 25/30 satisfactory result (83%)

 

Lateral Opening Wedge Femoral Osteotomy

 

Indications

- technically much more simple than opening wedge

 

Disadvantages

- lengthen leg

- higher risk of non union

 

Distal Femoral Osteotomy Guide wireDistal Femoral Osteotomy Puddhu Plate

 

Technique

- standard lateral approach

- distal femoral osteotomy above collaterals

- open wedge, check with diathermy lead

- 2 x tricortical iliac wing wedges

- plate fixation / Puddhu plates / distal femoral locking plate

 

Lateral Distal Femoral Osteotomy

 

TKR post distal femoral osteotomy

 

Nelson et al JBJS Am 2003

- 9 patients

- average interval from osteotomy was 14 years

- average age at time of TKR was 44

- every case required a constrained prosthesis

- technically demanding

- femoral IM rod tended to place femoral component in varus

- 2 excellent, 5 good and 2 fair results

- inferior to primary TKR

 

 

Preoperative Calculations

Calculate Desired Correction on Long Leg Views

 

1.  Simple Calculations

 

Measure anatomic femoral tibial angle

- normally 5-8o

 

Calculate correction desired

- need to overcorrect to 8o femoro-tibial alignment

- or correct to mechanical axis of 180o

 

HTO Long Leg Alignment Measurements

 

2.  Miniacci method

 

HTO Miniacci Method

 

A. Draw the predicted mechanical axis of the affected limb on the full-length radiograph

- connecting a point from the center of the hip to

- a point of new desired weight bearing axis on lateral tibial plateau

- one third of the way from the center of the knee to the lateral margin

- this is line A

- extend this line to the level of the ankle

 

B. Make a second line (line B)

- from the point on the proximal medial tibia that will be the pivot point of the osteotomy

- to a point in the center of the ankle

 

C. Draw a third line (line C)

- from the medial pivot point to the mechanical axis of the ankle

 

Angle (X)

- between the second and third lines (lines B and C)

- this is the angle of the wedge to be resected

 

Must then use trigonometry to calculate wedge height or rule of thumb

 

Calculation of Wedge (Closing Wedge)

 

1.  Rule of Thumb Method

 

Bauer 1969 

- estimates 1mm resected wedge = 1° correction

- this relies on average tibial width of 56mm 

- average tibial width at the flare is 75.2mm 

- Bauer's estimation tends to under correct

 

Example

- 12o correction, 12 mm wedge laterally

 

2.  Trigonometry Calculation

 

Tan Angle = opposite/adjacent

 

Wedge height medially = tibial width X Tan angle correction required

 

Intra-operative Checks

 

Use diathermy lead

- centred on femoral head

- centred on talus

- held straight

- ensure passes over lateral tibial plateau

 

HTO Diathermy Lead Femoral HeadHTO Diathermy Lead Centre Talus

 

 

 

 

 

 

Technique Closing Wedge

HTO Lateral Closing Wedge AP 1HTO Lateral Closing Wedge 2HTO Lateral Closing Wedge Lateral

 

Position

- GA, IV Abx

- supine on radiolucent table

- no nerve blocks (eidural / sciatic / femoral)

- knee roll / lateral support

- II available

 

Incision with knee at 90°

- midpoint tibial tuberosity & fibular head

- extend proximally to LFC

- incise deep fascia / ITB in line with incision

- reflect underlying T ant & EDL anteriorly

- expose proximal tibia anteriorly and posteriorly

 

Anterior Tibio-Fibula joint 

- must release

- place osteotome in joint to gauge direction & remove sliver of head medial fibular head

- locate & cauterize the Lateral Inferior Genicular Artery

- protect the CPN by staying superior to neck

- must leave LCL and biceps attached

 

Two threaded guide wires at superior level osteotomy

- under II guidance

- 2cm distal to joint in AP and lateral

- parallel to posterior slope

 

Osteotomy Jigs

- attach to superior 2 guide wires

- guide saw blade to hit superior osteotomy at medial cortex

- variable angles involved

 

Soft tissue protection crucial

- homan retractor anteriorly under patella tendon

- dissect soft tissue subperiosteally off posterior tibial cortex

- Homan to protect posterior structures

 

Osteotomy

- superior and inferior

- attempt to leave medial cortex intact

- must divide anterior and posterior cortices in full

- try to remove wedge of bone intact

- medial aspect of wedge difficult to remove

 

Straighten knee & close osteotomy

- do so slowly

- allow stress relaxation to occur

 

Check correction

- diathermy lead

- from centre of femoral head to centre of ankle

- must pass through lateral plateau

- if insufficient must recut distally

 

Stabilise ostetomy

- ORIF with 2 x staples / plate 

- suture ITB & deep Fascia over drain

 

Post op

- splint

- monitor overnight for compartment syndrome

- PWB 6/52

 

 

 

 

Technique Opening Wedge

 

HTO Opening Wedge APHTO Opening Wedge Lateral

 

Position

- patient supine on radiolucent table

- place ECG lead and artery clip over centre of femoral head

- useful to put II ipsilateral to leg, and place knee on cassette

- can get repetitive AP and lateral as needed

- tourniquet, IV ABx

- may need to be able to take iliac crest bone graft

- can get pre-prepared allograft wedges (Arthrex)

 

Equipment

- company specific jigs to guide tibial osteotomy

- puddhu plate system from Arthrex

- medial locking plate for larger corrections > 20o

- synthetic / allograft autograft bone graft wedges

 

Incision

- medial

- close to midline to incorporate into later TKR

- elevate pes and MCL, close later

 

Exposure

- must expose entire posterior tibia subperiosteally

- combination Bristow and Cobbs

- should be able to place finger entirely across tibia to proximal tibio-fibular joint

- expose behind PT above TT

- place Langenbeck / Homan retractors anteriorly and posteriorly

 

HTO Opening Wedge Puddhu Plate

 

Oblique Osteotomy

- entry is 5 cm distal to joint line aiming  for tip fibula head

- osteotomy must pass above TT

- must leave enough proximal bone laterally to avoid fracture (2cm)

- leave the proximal tib-fib joint intact to stabilise laterally

- don't penetrate lateral cortex

 

Arthrex guide

- place superior pin parallel to joint line

- should aim laterally for where the osteotomy is to exit (2cm below joint line)

- apply jig

- place 2 inferior break off pins in line with proposed osteotomy

- ensure parallel to tibial joint line / reconstruct posterior slope

- apply cutting block

- use oscillating saw

- stop 2 cm short of lateral cortex (mark on blade length that is 2 cm short of length of pins)

- check repeatedly on II

 

Note

- want to make osteotomy parallel to posterior slope of HTO

- put pins in and check on lateral II before cuts

- otherwise can increase / decrease slope

 

HTO Lateral Xray

 

Opening of wedge

- use osteotomes to complete osteotomy

- need to ensure get anterior and posterior cortex

- if having difficulty may need to perform fibular osteotomy

 

Stabilisation

- insert trial wedges of desired thickness (i.e. 10 mm)

- ensure weight bearing axis now passes through lateral joint (diathermy lead)

- insert appropriate angle Puddhu plate

- release trial wedges so the bone rests on the plate and recheck alignment

- secure with locking screws

 

Bone graft

 

A.   Insert combination of tricortical and cancellous bone graft

- tamp cancellous in lateral wedge

- then insert tricortical iliac crest graft (take same size as opening wedge)

 

B.  Insert predesigned allograft wedges

 

Post op

 

Insert a drain subcutaneously in skin, as bleeding v common and closure difficult

- elevate on braun  pillow for 48 hours

- monitor compartment syndrome

- PWB 6/52

- monitor for union

 

HTO Opening Wedge United

 

Results

 

Allograft v autograft

 

Yakobucci et al Am J Sports Med 2008

- 50 patients with average opening wedge 10o

- inserted corticocancellous allograft wedge

- 2/50 (4%) not united at 4 months

 

HTO Allograft

 

Synthetic graft

 

Koshino et al JBJS Am 2003

- 21 patients with 2 x HA wedges and plate

- good correction and functional outcome in all patients

 

 

 

Knee Arthroscopy

Portals

 

1.  Anterolateral

 

Viewing portal

- 1cm lateral to patella tendon

- 1cm above joint line

- 1 cm below inferior pole patella

 

Problems

- too medial, in fat pad

- too high, limitation by patella, difficult to see posterior horns

- too low, damage anterior horn meniscus

 

Limitations

- PCL

- anterior horn LM

- posterior horn MM in tight knees

 

2.  Anteromedial

 

Instrumentation portal

- also used for viewing posterior horn MM, anterior horn LM

- 1 cm above joint line

- 1 cm lateral to patella tendon

- 1 cm below inferior pole patella

 

Can be useul to insert needle first

 

3.  Superolateral portal

 

Landmarks

- just lateral to quadriceps tendon

- 2.5 cm above SL corner of patella

 

Uses

- evaluate PFJ

- drainage portal

- resection plicae

- removal loose bodies

 

4.  Posteromedial portal 

 

Must

1.  Have distended the knee with saline so the soft spot bulges

2.  Flex the knee to 90o so NV bundle falls posteriorly

3.  Marked the bony landmarks prior

 

Landmarks

- 1 cm above joint line

- 1 cm posterior to MFC

- flex knee slightly

- introduce needle & then skin incision and blunt dissect to post capsule

- pass switching stick / insert cannula over it

 

Anatomical

- anterior to medial head gastrocnemius

- posterior to MCL / MFC

- superior to pes

 

Uses

- posterior horn tears MM

- loose bodies

- PCL reconstruction / posterior tibial joint line debridement

 

Risks

- saphenous nerve

 

5.  Posterolateral Portal

 

Technique

- distend joint with fluid

- knee at 90o

 

Landmarks

- where posterior margin of femoral cortex intersects posterior aspect of fibula

- 2cm above joint line

- behind LFC

 

Knee Posterolateral Portal

 

Anatomy

- behind LCL

- anterior to lateral head gastrocnemius

- between ITB and biceps

 

Uses

- repair posterior lateral meniscus

 

Risks

- CPN

 

6.  Accessory far medial and lateral portals

 

2.5 cm medial and lateral to standard anterior portals

 

Uses

 

Far medial portal

- gives good access to body of lateral meniscu

- angle is above the tibial spines

 

7.  Central trans-patella portal

 

Landmarks

- midline

- 1cm below inferior pole patella

 

Uses 

- ACL

- OCD

 

Incisions for Inside / Out Sutures or Removal of Loose Bodies

 

Posteromedial incision

 

Placed at the posterior aspect of MFC

- knee in 90° flexion

- 3-4 cm long

- 1/3 of incision above joint line & 2/3 below

- medial head gastrocnemius posterior

- MCL anterior

- infrapatellar branch of saphenous nerve 1 cm above joint line

- avoid saphenous nerve which runs in fat above the sartorius

- open sartorius fascia, retract to protect nerve

- expose capsule

 

Posterolateral incision

 

Centred on joint line

- knee at 90o

- LCL

- biceps inferiorly to protect CPN

- must dissect lateral gastronemius off capsule and retract

- protects posterior neurovascular bundle

 

Complications

 

Incidence

 

Uncommon

- overall < 1%

- NV complications rare

- incidence 0.1%

 

Nerve Injury

 

From incorrect placement of portals

 

Risk reduced by

- correct placement

- use of blunt trocar

 

1.  Infrapatellar branch saphenous nerve

- anteromedial portal

 

2.  Saphenous Nerve

- most commonly injured

- usually from posteromedial portal

- needles during arthroscopic in-out meniscal repair

 

3.  Common Peroneal Nerve

- second most commonly injured

- direct puncture for posterolateral portal

- passage of needles for arthroscopic meniscal repair

- entrapment by sutures of meniscal repair

 

Can be avoided by

- flexion of knee

- direct dissection & identification

- use retractor to deflect needles

 

Tourniquet related Neuropraxia

 

Risk reduced by

 

1.  Minimal duration 

- < 90 min UL 

- < 120 min LL

 

2. Minimal pressure

- < 250 UL

- < 350 LL 

 

3. Adequate cuff width

- > 1.2 limb diameter

 

4. Positioning

- direct pressure on nerve from inappropriate positioning

 

RSD 

 

Uncommon

 

Considered when

- prolonged pain > than expected

- vasomotor disturbance

- stiffness

- trophic changes

 

Compartment Syndrome

 

From extravasation of fluid for distension of joint

- fluid may enter through rupture of synovial pouch

- into thigh through suprapatellar pouch

- into calf through semimembranosus bursa

 

Risk reduced by

- minimise water pressure used

- minimise duration of procedure

- absorbable solution

- minimise number of capsular punctures

- avoid 6/52 post injury

- palpate leg at end of procedure

 

Compartment Syndrome Post ACL Reconstruction

 

Management

- usually will resolve

 

1.  Keep patient asleep

- elevate foot

- compress with eshmarc bandage to remove water

 

2.  Mini incision in fascia

- allows water to escape

- will see muscle is very oedematous

 

3.  Ensure patient has not had vascular injury

 

 

 

Knee Dislocation

General Management

Knee Dislocaton APKnee Dislocation Lateral

 

Definition

 

2 or more ligaments disrupted

- multi-ligament knee

 

ACL + PCL + one of collaterals 

- knee dislocation

 

Incidence

 

Rare

- 0.12%

 

However incidence likely underreported

- many spontaneously reduce

 

Shenck Anatomic Classification 1992

 

KD-I: One cruciate + one collateral

 

KD-II: ACL and PCL torn

 

Knee Torn ACL and PCL0001Knee Torn ACL and PCL0001

 

ACL PCL MRIACL PCL MRI 2

 

KD-IIIM: ACL / PCL + MCL 

 

Knee Dislocation ACL PCL MCL MRI 1Knee Dislocation ACL PCL MCL MRI 2Knee Dislocation ACL PCL MCL MRI 3

 

KD-IIIL: ACL / PCL + LCL / PLC

 

KD-IV: Both cruciates and collaterals

 

KD-V: fracture dislocation

 

N nerve C arterial

 

Ligament injuries

 

PCL

- 80% femoral avulsion

- can attempt repair

 

ACL

- 30% avulsion

 

Associated injury

 

Vascular injury 40%

Nerve injury 20%

Fractures 60%

 

Vascular Injury

 

Incidence

- 30 - 40%

 

Arterial spasm is not a diagnosis

- must assume thrombus formation

 

Direction of tibia important

- tibia anterior = intimal tear

- tibia posterior = arterial disruption

 

Knee Dislocation APKnee Dislocation Tibia Posterior

 

Popliteal artery tethered

- proximally in Hunters Canal under fibrous arch of adductor magnus

- distally under fibrous arch of soleus

- in middle by 5 geniculate arteries

 

Problem

- genicular vessels provide poor collateral flow 

- amputation with vascular injury > 8 hours = 85%

 

Normal angiogram

 

Angiogram Normal 1Angiogram Normal 2

 

Nerve Injury

 

Tibial nerve

- not tethered proximally 

- less commonly injury

 

Common Peroneal Nerve

- tethered behind biceps and around neck of fibula

- functional return only 20%

 

Niall et al JBJS Br 2005

- 25% injury rate to CPN

- < 50% recovery rate

 

Mechanism of injury

 

High energy (MVA)

 

Low energy (sport)

- low energy has 5% arterial injury

 

Examination

 

Extensive soft tissue injury

- swelling +++

 

Open / compound dislocation

 

Open Knee Dislocation

 

Obvious ligamentous laxity

 

Neurovascular status

- pulses, capillary refill, skin colour

- any concern, vascular investigation

 

Reduction

 

Reduce in ER

- if stable can leave in brace

- if unstable, need external fixator

 

Dimple sign  

- due to trapping of medial capsule & MCL

- after posterolateral dislocation

- MFC buttonholes through medial ST

- get dimpling along the medial joint line

- usually seen after closed reduction of PL knee dislocation

- non anatomic reduction achieved

- requires open reduction

 

Knee Dislocation Medial DimplingKnee dislocation button holed MFC

 

Xray

 

Direction of displacement (of tibia)

 

Anterior dislocation 

- tibia anterior

- most common 

- hyperextension + varus/valgus

 

Anterior Tibial Stress XrayKnee Dislocation Posterior Subluxation

 

Posterior dislocation

- tibia posterior

- flexed knee, posterior force

 

Posterior tibia knee dislocationPosterior Tibial Subluxation Stress Xray

 

Other signs

- PCL bony avulsion

- posterior subluxation tibia

- fibula head avulsion

- segond fractures

 

Vascular investigation

 

Indications for angiogram

- cold / white foot

- ABI < 0.9

- asymmetry of pulse

- any concern regarding vasculature

 

Options

- CT angiogram

- MR angiogram

- on table / vascular lab angiogram

 

CT angiogram

 

100% sensitive and specific

 

Knee Dislocation Normal CTa

 

Angiogram

 

5-7% false positive rate

 

II Control

- open approach to proximal femoral artery

- place catheter in artery with 3 way tap

- 20mls Omnipaque / water soluble dye 

- II over distal femur

- repeat for proximal tibia

- must show films to radiologist for interpretation of subtle signs

 

Do in Angiography suite if not threatened otherwise on table

- check bleeding tendencies / coags

- allergies

 

Most common method of vascular repair

- flex knee

- detach medial head of gastrocnemius

- resection 

- reversed saphenous vein graft / synthetic graft

- bridging external fixator

- fasciotomy if vascular injury

 

MRI

 

Early to examine ligaments

 

Assess

- ACL / PCL

- PLC

- LCL / MCL

 

Knee Dislocation MRI ACL PCL torn

 

Management

 

Emergency Surgery

 

Absolute Surgical Indications 

 

1. Arterial injury 

- external fixator

- vascular surgery

 

2.  Irreducibility

- open reduction

- apply external fixator if unstable in brace

 

3.  Open dislocation / washout

- do not perform early ligament reconstruction

- apply external fixator if unstable in brace

 

4.  Compartment syndrome

 

Definitive Management

 

Non operative

 

Brace 30 - 40o 6 weeks

- for elderly

- used to place steinmann pin across joint

- may need external fixator for obese patient

- will get very stiff

 

Operative

 

Issues

 

Operative v Nonoperative

 

Levy et al Arthroscopy 2009 Systematic Review

- studies consistently show improved outcomes with operative management

 

Early versus Late Surgery

 

Levy et al Arthrscopy 2009 Systematic Review

- early treatment consistently results in higher outcome scores

- easier identification of tissues

- some tissue amenable to repair

 

Repair versus Reconstruction

 

1.  PLC

- usually treated with repair of avulsions

- reconstruction of midsubstance injuries

 

Stannard et al Am J Sports Med 2005

- repair v reconstruction of PLC

- improved outcomes with reconstruction

 

2.  PMC

- usually treated with repair of avulsions

 

Stannard et al AAOSM 2009

- reduced failure rates with reconstruction versus repair

 

3.  ACL / PCL

- typically reconstructed

 

Harner et al JBJS Am 2004

- reconstuction of ACL / PCL

- good results reported

 

Owens et al J Orthop Trauma 2007

- repair of ACL and PCL

- good results reported

 

Rehabilitation

 

Mook et al JBJS Am 2009

- systematic review

- increased instability seen with immobilization compared with early mobilization

- increased FFD and loss of flexion seen with immobilization

 

Thompson et al 2006 AAOSM 2006

- prospective randomized trial of hinged external fixation v hinge brace

- early results showing reduced instability and reduced failure rates after ligament reconstruction

 

Timing

 

Wait 2 - 3 weeks

- monitor vascular status

- allow swelling to settle / ice +++

- obtain some ROM if able to do with stability in ROM brace

 

Beyond 3 weeks, collateral and PL structures too scarred for early repair and will need late reconstrustion

 

Algorithm

 

1.  External fixator / brace

- maintain reduced

 

2.  Consider CTa / MRa

- exclude vascular injury

 

2.  MRI

 

3.  Surgery 

 

Surgical Options

 

1.  ACL + Posterolateral Corner

 

ACL reconstruction

- autograft / allograft / synthetic

 

Hamstring ACL PLC AdvancementHamstring ACL PLC Advancement Lateral

 

Lars ACL PLC Advancement APLars ACL PLC Advancement AP

 

PLC

- acute repair / reconstruct / advancement

- depends on specific injuries (i.e. midsubstance tears v bony avulsions)

- see Posterolateral Corner

 

2.  PCL + Posterolateral Corner

 

PLC

- acute repair / reconstruct / advancement

 

PCL

 

A.  Femoral avulsion

- repair if able to drill holes in MFC

- augment with LARS

 

B.  Midsubstance

- LARS /  hamstring reconstruction / allograft reconstruction

- single or double bundle

 

3.  ACL + PCL

 

Reconstruct both

- achilles allograft for PCL

- hamstring / tibialis anterior for ACL

 

ACL PCL DeficientPCL FemurPCL Graft

 

ACL PCL GraftACL PCL Recon APACL PCL Lateral

 

Knee Dislocation ACL PCL ReconstructionACL PCL Reconstruction PCL double bundle

 

4.  PLC / ACL / PCL

 

PCL

- reconstruct

 

ACL

- reconstruct

 

PLC

- repair / reconstruct

 

5.  ACL / PCL /  MCL

 

PCL

- reconstruct

 

ACL

- reconstruct

 

MCL

- grade 3: repair to tibia or femur with avulsion

- with midsubstance may need reconstruction with hamstring / tendoachilles allograft

 

Knee Dislocation ACL PCL MCL Reconstruction APKnee Dislocation ACL PCL LCL Reconstruction Lateral

 

6.  ACL / PCL / PLC / MCL

 

Combination of above

Technique ACL + PCL + Posterolateral Corner

Technique

 

Hamstring ACL

Allograft for PCL

Allograft LaPrade style reconstruction for PLC

 

Grafts

 

Hamstring for ACL

2 x Achilles allograft for PCL / PLC

- split one for PLC

 

Timing

 

Before 2 weeks

 

Set up

 

90o on bolster

Want to use 2.5 hours tourniquet time to pass ACL / PCL grafts

- let down to do posterolateral corner

 

Make vertical portals

- may need medial and lateral parapatella approaches

 

ACL / PCL

 

Assess PCL

- if femoral avulsion and good stump remains

- can consider femoral repair

 

Debridement of notch

- outflow is a problem

- use a posteromedial cannula

- must take hamstrings first or can injure them with cannula

 

Harvest hamstrings

 

Place posteromedial cannula

- need to be able to instrument PCL origin

- aids outflow

- direct visualisation with camera

- insert needle

- most common mistake is too anterior / inferior

- insert cannula

 

Assess meniscus / popliteus

- obvious lateral drive through sign

- prognosis for stability much better if meniscus intact

 

Graft preparation

 

Hamstrings as preferred

- over endobutton

 

Achilles allograft for PCL

- 10 mm wide x 25 mm long bone block

- 2 x drill holes with 2 x 1 ethibond

- make tendon slightly wider 12 mm

- tubularise distal end and leave long sutures

- will need to pass this end from intra-articular through tibial tunnel

 

Achilles Allograft InitiallyAchilles Allograft Final

 

Posterolateral grafts

- Achilles Allograft

- need two, one for LCL and one for popliteus

- create 8 x 25 mm bone blocks times two

- 2 x drill holes with 2 x 1 ethibond

- slightly wider tendon

- again, careful tubularisation with threads as will need to pass through fibular and through tibia

 

PCL Tibial Tunnel

 

Change to 70o scope

- under vision clear back of tibia to 1-2cm down in centre

- need tunnel to be as low as possible

- insert PCL guide under vision

- tibial tunnel is very midline

- ACL tibial tunnel will be much more medial to separate tunnels

- must aim for lateral aspect of posterior tibia

- check on xray

- ensure guide wire is in lowest part of PCL facet

- want at least 1 cm bone above 8 mm tunnel

- protect guide wire with curette via PM cannula

- ream 8 mm tunnel for achilles tendon

 

ACL

- drill appropriate size tibial and femoral tunnel (i.e. 7.5 or 8)

- endobutton technique useful as have one less screw in femur

 

PCL femoral tunnel

- clear MFC

- open incison medial knee

- elevate VMO

- use PCL jig 65o

- guide wire should exit in joint high and anterior

- sufficient distance from articular cartilage

- drill 10 mm tunnel for achilles bone block from outside in

 

Pass PCL passing sutures

 

Will pass PCL allograft in through knee lateral portal

- often will need to make larger

 

A.  Tibial side

- pass bent houston suture passer up through tibial tunnel

- retrieve from back of knee and out lateral portal

- pass 1 nylon loop so loop is intra-articular and out of lateral portal

- clip

 

B. Pass houston suture passer into knee via femoral tunnel in MFC and out lateral portal

- retrieve 1 nylon loop so loop is intra-articular and out of lateral portal

- clip

 

Pass ACL passing suture

- beath pin up femoral ACL tunnel

- retrieve loop 1 nylon out tibial tunnel

 

Pass and secure PCL Graft

- using loops out AL portal

- pull achilles bone block into femoral tunnel

- pull tendon end into knee and around tibial tunnel

- secure femoral end with 7 x 25 mm screw outside in

- don't secure tibial end

 

PCL Allograft Tibial endPCL Allograft tibial component into knee

 

Pass ACL graft

- ensure passing sutures are anterior to PCL

- flip endobutton

- don't secure tibial end

 

Posterolateral corner

 

Approach

 

Lateral hockey stick incision

 

Fascial window posterior ITB

- identify and protect CPN

- CPN behind biceps femoris

 

Fascial window mid ITB

- identify femoral epicondyle / LCL insertion

 

Popliteus femoral insertion

- identify point, insert beath pin

- 8 mm tunnel, 30 mm deep

 

LCL femoral insertion

- 18 mm from popliteus

- go posterior and superior

- 8 x 30 mm tunnel

 

PLC Popliteus and LCL Femoral Drill HolesPLC Allograft Femoral Screw

 

Fix Popliteal and LCL bone blocks

- insert 5 mm suture anchor first below each site

- secure bone block with 7 x 25 mm screw

- augment this with sutures from suture anchors

 

Drill LCL fibula tunnels

- elevate tissue anteriorly from fibula head

- tunnel must be sufficiently low to avoid fracture

- aim lateral to medial

- finger / spoon behing head / anterior to gastronemius

- 7 mm tunnel

 

Drill Popliteus tibial tunnel

- incision anterolaterally on tibia

- beath pin anterior to posterior

- again, protect posterior structures

- drill 8 mm

 

Pass popliteal tendon

- pass achilles tendon deep to ITB fascia

- houston suture passer anterior to posterior through tibial tunnel

- retrieve and pass loop nylon

- retrieve allograft anteriorly through tibial tunnel

 

PLC Pass Popliteus Tendon deep to fasciaPLC Popliteus Deep to FasciaPLC Popliteus Allograft Anterior Through Tibia

 

Pass LCL tendon

- pass tendon deep to ITB

- want to pass anterior to posterior

- this is because LCL normally attached to anterior fibula

- pass loop nylon again with Houghston suture passer

- can be difficult to pass tendon through fibula

 

PLC LCL Allograft Deep to FasciaPLC LCL Allograft Passed Through Fibula

 

Take a break before final and important part (tensioning) - get a drink and a snack

 

ACL PCL PLC Pretensioning

 

Tension Grafts

 

1.  PCL

- 90o

- pull tibia forward

- tension graft +++

- because the tunnel on the tiba is very anterior, bone is very hard

- line to line screw, may need to downsize

- 8 x 35 screw (longer as tunnel is longer)

- have anterior draw on tibia and foot IR

- secure with post / staple

 

PLC Tension PCL 90 Degrees

 

2.  Popliteus

- do second as helps to support PCL

- 90o and foot IR

- line to line screw

- 8 x 25, secure with post / staple

 

PLC Tension Popliteus

 

3.  LCL

- 30o from full flexion, full IR

- front to back 7 x 25 screw

- secure distally on fibula with suture anchor

- pass back up femur deep to fascia

- secure with soft tissue washer over large fragment screw

- can sutures 2 limbs of LCL achilles graft together to improve tension

 

PLC Tension LCL at 30 DegreesPLC LCL second limb PassedPLC LCL second limb secured to femur

 

4.  Secure ACL

- screw and washer

- tension at 0o / full extension

 

PLC ACL tensioned full extension

 

Post PCL PLC

Knee OA

Non Operative Management

 

Options / ELM POPI

 

Education

Lifestyle Management

- weight loss

- reduce sport

Physiotherapy

Orthotics

- walking stick

- braces

Pharmaceuticals

- NSAIDS

- acetominophen

- glucosamine

Injections

- cortisone

- hyaluronic acid

 

Definition OA

 

Loss of integrity of the articular cartilage

 

Outerbridge Grading

 

I   Fibrillation

II  Fragmentation < 1/2 depth

III Fragmentation > 1/2 depth

IV  Erosion to bone

 

Investigations

 

Rosenberg view / tunnel view

- 45o flexion weight bearing view

 

Rosenberg View

 

Rationale

- most early cartilage loss is in 30-60o flexion range

- can be missed with view in extension

 

Knee OA APKnee OA Rosen View

 

Glucosamine

 

Action

- stimulates proteoglycan synthesis by chondrocytes 

- has mild anti-inflammatory properties

- however, therapeutics seems to be via PG independent mechanism

 

Results

 

Several clinical trials in patients with OA

- superior results with glucosamine sulfate compared to placebo

- reduced incidence of adverse effects

 

JBJS Am 2000

- meta-analysis

- glucosamine and chondroitin are effective for improving outcomes

- the magnitude of effect is unclear because of inconsistencies in study design

- dependence on industry support for study execution

 

Advantage

- harmless

 

Disadvantage

- reasonably expensive

- $30 / month

 

Reasonable to trial and continue if works

 

Hylan Injections / Viscosupplementation

 

Compound

 

Hylans are cross linked molecules of Hyaluronan

- derived from rooster combs or newer synthetic compounds

 

80% hydrate Hylan A

- water soluble molecule of approximately 6 million MW

- a marked increase in elastoviscosity compared to hyaluronan

 

20% hydrated Hylan B

- a solid derivative with continuous cross-linking between all the constituent molecules

- forms a more stable, highly elastic hydrated molecule

 

Options

 

Synvisc

- 3 x doses

 

Durolane

- synthetic

- single dose

 

Cost

 

$4 - 500 per treatment

 

Rationale

 

In inflamed joint

- decreased concentration and MW of hyaluronan

- stimulates inflammation

 

OA

- synovial fluid significantly reduced viscoelasticity

- synvisc replaces the pathological synovial fluid

- supplementing elasticity and viscosity thereby reducing pain and improving mobility

 

In vitro effects

- cell migration and phagocytosis slowed down or inhibited in elastoviscous environment

- nociceptors also sensitive to visco-elastic state

- high MW hyaluronan also decreases concentration of bradykinins etc

 

Results

 

Wobig Clin Ther 1998

- 57 knees 3 x 2ml injections each 1 week apart

- vs 60 knees saline injection

- 12 week end point

- X rays grade II-III

- 40% better pain relief in control

- 82% better pain relief in synvisc

 

Bellamy et al Cochrane Review

- evidence supports use of HA injection in knee OA

 

Complications

 

1% risk of acute allergic reaction

- sudden swelling and pain

- treat with cortisone injection

 

Technique

 

Patient with Grade 2/3 OA

- trial injection

- no sport / high impact activities for a few days

- takes 2 weeks to work

- needs to get 6 - 9 months of improvment to repear

 

Weight loss

 

Wt loss > 5 kg in women halves risk of degenerative OA by 50%

 

Physiotherapy

 

Quadriceps rehab shown to improve function without worsening arthritic symptoms

 

Walking Stick

 

Cane in the opposite hand decreases weight bearing load by 30 - 60%

 

Braces

 

1.  Compressive

- neoprene

- provide warmth

 

2.  Supportive

- hinged brace (varus-valgus)

- ACL brace

- PF braces

 

3.  Unloading

- unloading varus knees

- 3 or 5o

- expensive / need to be correctly fitted

- doesn't work on large obese knees due to fitting issues

- shown to decrease pain 

 

Knee Unloader Brace 3 Degree

 

Orthotics

 

Lateral heel wedge for varus knee

- shown to decrease pain in 50% patients

 

Arthroscopic Lavage 

 

Mechanism

 

Unclear

 

1.  Removal "Chemical Soup"

- cartilage debris

- crystals

- inflammatory factors

 

2.  Able to treat internal derangement at same time

- chondral flaps

- meniscal tears

 

Indications

 

A.  To postpone TKR

- young, mild OA, no malalignment

- loose bodies

- mechanical symptoms

- recent effusion

 

B.  Want to establish patient has severe enough OA to warrant TKR that you cannot see on X-ray

- staging OA

- HTO v TKR

 

Results

 

Kirkley et al N Eng J Med 2008

- RCT of moderate to severe OA

- arthroscopic lavage and debridement v physiotherapy / medical therapy only

- no difference in outcome

 

Herrlin et al Knee Surg Sports 2007

- randomised patients with degenerative / non traumatic medial meniscal tears

- arthroscopic debridement v exercise program

- no difference in two groups

 

 

 

 

Lower Limb Angle / Malalignment

 

Definition

 

Deformity causing alteration of mechanical axis from knee centre

 

Tibial Malunion APTibial Malunion Lateral

 

Aims

 

1.  Normal leg alignment

2.  Equal leg lengths

3.  Horizontal joint lines

 

Normal Anatomy

 

Mechanical Axes

 

A.  Coronal Mechanical Axis of Lower Limb

 

Line from centre femoral head to centre of ankle

- passes medial to the centre of knee 

- 10mm medial to the frontal plane centre

- medial tibial spine

- Llne of transmission of forces

 

Mechanical Axis Lower Limb

 

Sagittal Plane

 

Centre of femoral head to centre of ankle

- just anterior to centre of knee joint

- aids in passive locking of knee joint in full extension

 

B.  Femoral Mechanical Axis

- centre of femoral head to centre knee

 

Femoral Mechanical AxisMechanical Axis Tibia

 

C.  Tibial Mechanical Axis

- same as tibial anatomic axis

- centre plateau to centre of talus / ankle

 

Anatomical Axis

 

Femoral - Tibial anatomic axis

- centre of femoral shaft to centre of knee, then centre of tibia

- 6o valgus

- increased in shorter femurs

- decreased in longer femurs

 

Anatomic Axis FemurTibio-femoral Anatomic Axis

 

Femoral AA 

- piriformis fossa to centre knee joint

- 6o from mechanical axis

- to knee joint is 81° on lateral side

 

Hip

 

Femoral Neck-shaft angle 

- 125-131°

 

Femoral Neck Shaft Angle

 

mLPFA (mechanical Lateral Proximal Femoral Angle)

- line tip GT to centre femoral head

- 90o to MA

 

Knee

 

Knee joint

- 3o valgus relative to MA

- 6o valgus distal femur

- 3o varus proximal tibia

 

Post Slope 

- 9°

 

Proximal Tibial Slope

 

MPTA (medial proximal tibial angle)

- 87o or 3o varus

 

Medial Proximal Tibial AngleAnatomic Lateral Distal Femoral AngleMechanical Lateral Distal Femoral Angle

 

aLDFA (anatomical lateral distal femoral angle)

- 81o

 

mLDFA (mechanical lateral distal femoral angle)

- 87o

 

Mechanical Axis Deviation

 

Distance from centre of knee to MA in mm

 

Malalignment 

 

Effect

 

Uncertain if malunion causes OA

- theoretical cartilage overload

- evidence in animals of cartilage changes

- evidence of increased forces in cadavers

 

Kristensen Acta Ortho Scand'89 

- <15° Malunion = °OA  

 

Known problems

 

Femoral Procurvatum

- MA passes posterior to knee joint

- prevents knee locking

 

Other joints stiff 

- proximal tibial varus malunion

- can be compensated if mobile STJ

- if stiff subtalar joint, will notice abnormal gait

 

Ligamentous laxity of convex side of deformity

- increasing instability

- i.e. varus malunion with posterolateral instability

 

Chondral damage on overloaded side

 

Defining site of malunion

 

CORA

- centre of rotation of angulation

- lines of intra-medullary canals

- intersection is CORA

- site of deformity

- best site for correction

 

CORA APCORA Lateral

 

Indications for Surgery

 

Varus malalignment knee / ankle

- > 10o

 

Valgus malalignment knee / ankle

- > 15o

 

Mechanical axis deviation

- > 20 mm

 

 

MCL

ActionsMedial Knee Anatomy

 

Primary valgus stability

- alone at 30o flexion

 

Secondary restraint to

- anterior translation

- to ER

 

Secondary medial stabilisers

 

Contribute in extension

 

Static

- ACL

- medial capsule 

- posterior oblique ligament

- medial meniscus

- PCL

 

Dynamic

- pes anserinus

- SM

 

Hughston JBJSA 1976

- MCL resists 50% of applied force        

- anterior & posterior capsule 25%

- ACL & PCL 25% (PCL>ACL)        

 

Seebacher's 3 layers of medial knee

 

1.  Superficial layer

- deep fascia / fascia lata

 

2.  Middle layer

- patella retinaculum

 

3.  Deep layer

- MCL, OPL (oblique popliteal ligament), SM (semimembranosus), capsule

 

Anatomy

 

Medial Knee Anatomy

 

Superficial portion MCL

- triangular in shape

- origin medial epicondyle distal to adductor tubercle

- inserts proximal medial tibia

- deep to pes anserinus

- anterior margin free

- posteriorly blends with capsule and is attached to medial meniscus

- posterior to MCL is OPL

 

Deep MCL

- deep to MCL

- meniscofemoral and meniscotibial ligaments

- capsular thickening

 

Semimembranosus

- attaches to the posteromedial corner of the tibia

- just below the joint line

- important dynamic stabiliser

 

Oblique Popliteal Ligament

 

Thickening of posteromedial capsule

- extension of semimembranosus

- originates from adductor tubercle

 

3 insertions

- superficial arm from femur to tibia posterior to MCL, running over SM to blend with pes

- tibial arm attaches to medial meniscus then to proximal tibia

- deep arm is an extension from SM to posterior capsule

 

Pes anserinus

 

Runs superficial to MCL

- 3 components

 

Say Grace before Tea

- Sartorius

- Gracilis

- Semitendinosus

 

The saphenous nerve and small saphenous vein emerge between sartorius and gracilis

 

Mechanism of injury

 

Valgus force coupled with ER injures 

OPL as well as MCL

 

Site of Injury

 

MCL usually tears at femoral end

- laxity more likely at tibial end

 

Associated Injuries

 

1.  ACL 

- grade II MCL has a 70% association with ACL

 

2.  Meniscus

- most common with combined MCL & ACL injury

- lateral meniscus more common 3:1 with ACL tear 

- O'Donaghue triad rare

- Shellbourne 163 cases >50% had lateral meniscus tear

 

Examination

 

Discreet tenderness at femoral or tibial insertion of MCL

 

Tested in extension & 30° flexion

 

Remember to test both sides

- compare to contralateral side

 

Lax in extension

- tear to secondary constraint

- ACL / PCL / medial capsule

 

Grading

 

Grade 1 / Laxity in flexion 3-5mm

 

Indicates mild sprain of MCL

- up to 1/3 torn

- usually no laxity in extension

 

Grade 2 / Laxity in flexion 5-10mm

 

Indicates moderate sprain of MCL

- 1/3 to 2/3 torn

- usually no laxity in extension

 

Grade 3 / Laxity in flexion >10mm

 

Indicates complete disruption of MCL

- no endpoint

 

Usually lax in extension

- indicates disruption to secondary restraints

 

Also may have

- ACL laxity

- OPL instability / positive anterior draw in ER

- PCL laxity 

 

X-ray

 

Usually normal in acute injury

 

Bony Avulsion

 

MCL Bony Avulsion

 

Pellegrini-Stieda Lesion 

- calcification at insertion of femoral MCL

- indicative of chronic injury

- can rarely be symptomatic

- requires excision of calcification +/- reconstruction MCL if needed

 

Pellegrini Steida Lesion

 

MRI 

 

Acute

 

1.  Femoral injury

 

MRI Grade 3 Femoral Avulsion MCLMCL acute grade 3 Femur MRI

 

2.  Tibial avulsion

- can be flipped above pes

- will not heal

- will require surgery

 

3.  Midsubstance

- rare

 

MCL Midsubstance Tear MRI 1MCL Midsubstance Tear MRI 2

 

Chronic

 

See thickening of ligament

 

MCL Chronic Femoral Thickening on MRIMCL Chronic Femoral Thickening

 

Arthroscopy

 

Will see lift off of the medial meniscus

 

Arthroscopic Lift off of medial meniscus in MCL injury

 

Management

 

Non operative Management

 

Indication

- isolated injury

- no ACL / meniscal injury

- no displaced tibial avulsion

 

ACL + MCL

 

Delayed ACL reconstruction

 

Manage MCL non operatively as per below

- delayed ACL reconstruction if required

 

Zaffagnini et al JBJS Br 2011

- 3 year follow up of ACL reconstruction with grade II MCL treated nonop

- no impact on AP instability at 3 year follow up

 

Immediate ACL reconstruction

 

Halinen et al Am J Sports Med 2006

- RCT of acute ACL reconstruction in patients with grade 3 MCL

- operative v non operative management of MCL

- no difference in the two groups

 

Millett et al J Knee Surg 2004

- early ACL reconstruction with non operative management MCL in 18 patients

- at 2 year follow up no graft failure or valgus instability

 

Algorithm

 

Grade 1

 

Control pain & inflammation

- RICE 

- analgesia

- weight bear as tolerated

- ROM exercises

- muscle-strengthening exercises once FROM

 

Grade 2

 

As above plus hinge brace for 2 - 4 weeks

A.  Protect against valgus stress

B.  Full range if proximal MCL tear

C.  15° extension block if distal tear MCL or POL tear as well

 

Grade 3


Aim

- prevent full extension

 

6/52 in ROM hinged brace

- 30-60o for 2/52

- 30-90o for 2/52

- full range for 2/52

 

Results

 

Marshall et al Clin Orthop 1978

- demonstrated equal results with operative v non operative treatment of MCL

 

Operative Management

 

Indications

- displaced tibial avulsion

- displaced bony femoral avulsion

- chronic MCL instability

- MCL instability after ACL reconstruction

 

Bony MCL Avulsion

 

Elevate VMO

- repair with staples

 

MCL Bony Avulsion IntraopMCL Bony Avulsion Intraop 2

 

MCL Bony Avulsion ORIF APMCL Bony Avulsion ORIF Lateral

 

Stener Lesion

 

MCL Stener Lesion

 

Chronic MCL reconstruction

 

1.  Distal MCL MCL Advancement

- if detached from tibia

- double row repair (as for rotator cuff) increases surface area for healing

 

Distal Tibial Advancement 1Distal Tibial Advancement 2

 

MCL Tibial AvulsionMCL Tibial Avulsion Double Row Repair

 

2.  Proximal MCL Advancement

 

Proximal MCL Advancemetn 1Proximal MCL Advancement 2Proximal MCL Advancement 3

 

Indications

- proximal laxity

 

Options

A.  3 x figure 8 stitches to imbricate MCL and POL proximally

- tie over screw

- tighten MCL and POL

 

B.  Detach MCL

- 2 x distal suture anchors, pass sutures through tendon

- proximal staple

 

MCL Reconstruction APMCL Reconstruction Lateral

 

MCL Advancement APMCL Advancement Lateral

 

3.  Reconstruction of MCL and posteromedial complex (OPL / SM)

 

A.  Semitendinosus

 

MCL Reconstruction 2 Incision

 

Technique

- left attached distally

- re-routed more posteriorly on tibia around screw and soft tissue washer

- to medial epicondyle / isometric centre

- line of intersection of posterior femoral condyle and blumensaats

- insert wire and test isometricity in flexion / extension

- drill hole and fixate with RCI screw into blind loop of tendon

- return to tibia posteriorly to reconstruct OPL / secure with anchors and supplementary screw post

 

MCL Isometric PointMCL Reconstruction Tibial Screw Post

 

Lind et al Am J Sports Med 2009

- 50 patients followed up for minimum 2 years

- isolated instability / ACL and MCL / multiligament knee

- 98% had medial stability of normal or nearly normal

 

Kim et al JBJS Br 2006

- semitendinosus left attached distally

- reconstruction of MCL and OPL

- medial joint line opening within 2 mm in 22/24 knees

 

B.  Allograft

- doubled tibialis anterior

- tendoachilles allograft - bone block in medial femoral epicondyle

 

Marx et al CORR 2012

- 14 cases treated with tendoachilles

- good results in all cases

 

4.  Hughston Procedure

 

Technique

- advance femoral attachment of MCL

- advance femoral attachment of OPL

- stretch OPL anteriorly onto MCL

- reef SM forward to decrease slack

 

Surgical Approach to Medial Knee

 

Position

- knee flexed to 90o, over bolster

- tourniquet

- sandbag under hip

 

Incision

- hockey stick medial incision

- halfway between borders of tibia

- extends proximally to adductor tubercle

- distally to pes

 

Superficial dissection

- protect the saphenous nerve and small saphenous vein

- emerges from between sartorius and gracilis

- divide fascia over pes, reflect downwards

- divide medial patella retinaculum from VMO down to the pes

 

Deep dissection

- expose MCL running down to tibia under pes

- oblique popliteal ligament and SM are posterior to it

- can expose posterior capsule by carefully reflecting medial gastrocnemius posteriorly

- enter to joint if needed between posterior border of MCL and OPL

- identify proximal MCL attachment by elevating V medialis

 

 

Meniscus

Discoid Meniscus

DefinitionDiscoid Meniscus

 

Round or "D" shaped rather than crescenteric meniscus

- occupies > 70% of tibial surface

- 90% occur on lateral side

 

Epidemiology

 

Uncommon

- 1:100

- usually presents in children & adolescents

 

Case reports of

- medial

- bilateral

- medial and lateral in same knee

 

Aetiology

 

Controversial 

 

Theories

 

1.  Failure of resorption of embryological meniscus centre

- however the lateral meniscus is never discoid during normal development

 

2. Lack of normal fixation to posterior tibia

- discoid shape 2° hypertrophy of posterior horn

- due to excessive motion

 

Presentation

 

1.  Younger patients / adolescents < 15

- pain is commonest complaint

- clicking over lateral side

- recurrent effusions

- locking

 

2.  Adults

- may never be symptomatic

- some adults present with MRI showing discoid meniscus

- theory that meniscus is protective in these people

- have gone most of life without tearing meniscus

- only resect if unstable tear

 

Signs

 

Reproduce clicking at 110° flexion

 

Lateral joint line tenderness / mass

 

Effusion

 

Limitation of extension / FFD

 

Classification Watanabe

 

1.  Complete

- entire articular surface of tibial plateau covered by thickened abnormal meniscus

- minimal symptoms

- stable - i.e. capsular attachments intact

 

Complete Discoid MeniscusComplete discoid meniscus 2Complete Discoid Meniscus 3

 

2. Incomplete 

 

Normal peripheral attachments but not as extensive as complete type

 

Incomplete Discoid Meniscus

 

3. Wrisberg Type 

 

Unstable

- large posterior horn with no attachment to tibial plateau

- entire posterior portion hyper-mobile

- only attachment is Wrisberg Ligament

 

Most symptomatic

- displaced into intercondylar notch in extension

 

X-ray

 

Widened joint space

 

Discoid Meniscus Flattened Condyle Widened Joint Space

 

Flattening or cupping of plateau

 

Flat LFC

 

Hypoplastic Lateral Tibial Spine

 

MRI 

 

Obviously enlarged LM

See meniscus on 3 consecutive cuts

 

Discoid Meniscus MRI 1Discoid Meniscus MRI 2Discoid Meniscus MRI 3

 

Discoid Meniscus with intrasubstance degeneration

 

Management

 

Issue

 

There is a protective element to lateral meniscus

- resect only if painful tear / young patient

 

Aim

 

Convert unstable meniscus to a stable contoured one

 

Options

 

1.  Stable 

- partial central meniscectomy / saucerisation

 

2.  Unstable (Wrisberg type) 

- posterior capsular stabilisation / repair +/- saucerisation

 

Ahn et al Arthroscopy 2008

- 23 patients treated with posterior repair and partial central meniscectomy

- no reoperation at 51 months

- good symptomatic relief

 

3.  Prophylactic meniscectomy

- no role

 

Technique Saucerisation

 

Issues

- demanding and technically difficult

- takes 1 - 2 hours

- difficult to know how much to resect

- need to ensure don't damage chondral surfaces

- reported cases of rapid and severe chondrolysis post resection in young patients

 

Technique

- make incision with scissors in medial aspect

- resect posterior part

- saucerise laterally and anteriorly

- need to ensure don't detach anterior horn

 

Discoid Meniscus Saucerisation 1Discoid Meniscus Saucerisation 2Discoid Meniscus Saucerisation 3

 

Discoid Meniscus Saucerisation 4Discoid Meniscus Post Saucerisation

 

 

Meniscal Cysts

Epidemiology

 

Most common in lateral meniscus 9:1

 

Peak incidence 20-40

 

Aetiology

 

Probably 2° to infiltration of joint fluid into extra-articular tissues

- almost always associated with horizontal cleavage tear

- creates a flap valve in lateral 1/3 of LM

 

Symptoms

 

Usually present with pain

- activity related

 

May notice lump

- can vary in size with activity

 

Signs

 

Lateral mass associated with lateral joint line

- usually anterior to LCL

 

Best seen with knee in extension or slight flexion

- may disappear with knee flexion

 

Usually firm & immobile

- transilluminate

 

DDx

 

Ganglion

Cacific deposit in MCL / LCL

Osteochondroma

Soft tissue tumour

 

MRI

 

Meniscal tear + associated lateral meniscal cyst

 

MRI Lateral Meniscal CystMRI Lateral Meniscal Cyst 2MRI Anterior Lateral Meniscal Tear

 

Meniscal cyst 1Meniscal Cyst 2Meniscal cyst 3

 

Management 

 

Options

 

1.  Arthroscopic resection of tear

 

Tear may be difficult to identify

- careful inspection & probing

- often on undersurface of meniscus

- probe passed through tear into cyst

- usually results in decompression of cyst

- defunction flap valve with meniscectomy

 

Lateral Meniscus Cyst Normal Looking MeniscusLateral Meniscal Cyst Anterior Horn TearLateral Meniscal Cyst Defunction with Fluid

 

2.  Meniscal repair and cyst decompression

 

Results

 

Hulet et al Arthroscopy 2004

- incidence of 1.5% in 8000 knee arthroscopies

- 104 partial lateral meniscectomies

- intra-articular debridement in 91 and open cystectomy in 14

- 11 cysts recurred

- good or excellent results in 87%

 

 

Meniscal Repair

Indications for Repair

 

Only 20% repairable

 

1. Red / Red longitudinal tear

- outer 3mm / meniscocapsular junction

 

Meniscal Tear Red RedMensical Repair all inside

 

2. Red / White longitudinal tear

- only one side of tear vascularised

 

Meniscal Red White TearMeniscal Tear Red White Repair

 

3. Young patient

 

Contraindications to repair 

 

1.  White / White

2.  Complex / Horizontal / Radial / Degenerative tears

3.  Tears that are stable & < 1 cm

4.  Meniscal tear in setting of torn ACL that is not being reconstructed

- high risk of re-tearing meniscus if knee unstable

 

Principles of Repair

 

1.  Debride tear 

- stimulate proliferative response

- remove mature scar

- with shaver / rasp

 

2.  Trephine meniscocapsular periphery

- with spinal needle to promote vascular channels

 

3.  Reduce mensical tear

 

4.  Suture placement

A.  Open repair

B.  Inside out

C.  All inside

D.  Outside in

 

5.  Increase chance of healing in isolated mensical repair

- fibrin clot

- intercondylar notch microfracture

 

Techniques

 

1.  Open repair

 

Tibial plateau ORIF

- common to need to repair capsular avulsion of LM

- repair with 4.0 PDS / ethibond

 

2.  Inside out

 

Inside out Mensical Repair Structures at Risk

 

Technique

 

Require

- double armed sutures with long flexible needles

- use single or double cannula system

 

Make open posteromedial / posterolateral approach

- retrieve the sutures needles as they exit the joint capsule

- protects neurological structures (saphenous / CPN) from needle or suture injury

- sutures then tied over capsule

- pass in flexion to protect structures

 

Pass the needles about the tear

- vertical or horizontal mattress sutures

- absorbable or non absorbable 2.0 suture

- every 2-3 mm

 

Tie sutures over capsule

- tie in extension or will break when patient extends leg

 

Meniscal Repair Inside OutMeniscal Repair Inside Out

 

Posteromedial incision

- placed at the posterior aspect of MFC

- knee at 90°

- 3-4 cm long vertical incision

- behind MCL

- protect saphenous nerve which runs in fat above the sartorius

- open sartorius fascia, retract to protect nerve

- displace medial head gastrocneumius posteriorly

- expose capsule

 

Posterolateral incision

- centred on joint line, just posterior to LCL

- knee at 90o

- above biceps and therefore CPN

- palpate LCL anteriorly

- Biceps is retracted inferiorly to protect CPN

- must dissect lateral gastronemius off capsule and retract

- this protects CPN and posterior neurovascular bundle

 

3.  All inside

 

Instruments

- meniscal arrows (Biostinger, Meniscus Arrow)

- meniscal screws

- meniscal suture anchors (FasT-Fix, RapidLoc)

 

Technique FasT - Fix

- ipsilateral portal to view

- contralateral portal for instruments

- 2 x absorbable sutures anchors posteriorly

- may have to change portals for mensical body sutures

- pass first bioabsorbable anchors through meniscus and capsule

- retract and advance second anchor

- place anchor through meniscus (horizontal) or into capsule alone (vertical)

- advance knot, cut

 

All inside 1All inside 2All inside 3All inside 4

 

Meniscal Repair Posterior FastfixMeniscal Repair Posterior Fastfix Suture x 2Meniscus Post Repair

 

3.  Outside in

 

Indicated for anterior horn tears

- very difficult to get angle on the tear

- either with all inside or inside out

 

A.  Option 1

- camera in portal opposite to tear

- insert spinal needle through capsule and tear

- insert 1 PDS via spinal needle

- retrieve suture via anterior portal, tie a knot in end

- secure meniscus with knot

- repeat above step

- tie 2 sutures over outside of capsule

 

Anterior horn Meniscal TearAnterior horn meniscal tear Repair 1Anterior horn meniscal tear Repair 2

 

B.  Option 2

- insert PDS via spinal needle as above

- insert second spinal needle with loop PDS

- retrieve first PDS through that loop

- then pull single ended PDS back out through capsule
- tie over capsule

 

C.  Company made sets

- insert 2 hollow bore needles through capsule and meniscus

- insert single ended suture through one needle separate needle

- insert wire loop through other needle and retrieve

- tie over capsule through separate skin incision

 

Outside in Meniscal MenderMeniscal Repair Outside In First NeedleMensical Repair Outside In 2nd needle

 

Mensical Repair Outside In Advance SutureMeniscal Repair Outside In Retrieve with LoopMeniscal Repair Outside In

 

D.  Anchor repair

- insert anterior suture anchor

- pass sutures through meniscus and tie down

- technique used in meniscal transplant

 

Lateral Meniscus Anterior Horn TearAnterior Horn Tear ReducedAnterior Horn Tear Suture Passage

 

Anterior Horn Tear Suture Passage 2Anterior Horn Tear SuturesAnterior Horn Tear Final Repair

 

4.  Meniscal Root Repair

 

Definition

- tear of insertion of posterior horn of meniscus

- difficult to fix

- must repair down to bone

 

Technique

- ACL guide

- drill hole up into mensical root insertion

- use suture passer to secure meniscal root

- retrieve sutures down through bone tunnel in tibia

- tie over screw post

 

Mensical Root Repair 1Mensical Root Repair 2Mensical Root Repair 3Mensical Root Repair 4

 

Post operative rehab

 

Avoid weight bearing in flexion > 90o

- weight bear in extension / splint for 6 weeks

- range to 90o NWB

Meniscal Root Tears

Incidence

 

Up to 8% reported in ACL reconstructions

 

Natural History

 

Very poor

- leads to mensical extrusion

- increased tibio-femoral contact pressure

- rapid early OA

- equivalent to total meniscectomy

 

MRI

 

Findings

- meniscal extrusion

- meniscal ghost sign on sagittal (missing meniscus)

 

MRI Meniscal Root tearMeniscal Root Tear MRIMRI Meniscal Root Tear 3

 

Arthroscopy

 

Have to look either posteromedial or posterolateral to identify

 

Meniscal Root TearMeniscal Root Tear

 

Surgical Management

 

1. Suture anchor repair

- posterior compartment cannula

- insert cannula into posterior tibial plateau

- pass sutures and tie

 

2. Transtibial pullout repair

 

Technique

- use ACL guide

- pass under ACL / PCL to get to root insertion

- camera through posterolateral  / posteromedial portal

- pass beath pin under vision

- pass endobutton drill under vision

- debride insertion

- pass sutures through meniscal root (either labral suture passer or rotator cuff suture passer)

- retrieve through tunnel with houston suture passer

- tie over endobutton

 

Meniscal Root RepairMeniscal Root RepairMeniscal Root Repair 3

 

Mensical Root Repair Endobutton DrillMensical Root Repair Drill HoleMensical Root Sutures

 

 

 

 

Meniscal Tears

Mensical Tear Posterior Horn 1Mensical Tear Posterior Horn 2

 

Mechanism of Injuries

 

Rotational force incurred while joint partially flexed & extending

- caught between femoral & tibial condyles

- usually valgus & ER / varus & IR

 

Incidence

 

MM: LM 2:1

 

Medial Meniscus more common

- less mobile

- usually posterior horn tear

 

Acute ACL

- lateral Meniscus

 

Chronic ACL

- medial meniscus

 

Tibial plateau fracture

- 50% incidence

 

Relatively common in asymptomatic knees

- 13% < 45 years

- 36% > 45 years

 

Medial meniscus anatomy

 

C shaped fibrocartilage

- posterior horn larger than anterior horn

- capsular attachment on the tibial side is the coronary ligament

- thickening of the capsule from tibia to femur is deep MCL

 

Medial Meniscus NormalPosterior Horn Medial Meniscus Normal

 

Lateral meniscus

 

Semicircular

- covers a larger surface of the tibia than MM

- anterior and posterior horns attach closer to each other

- anterior horn adjacent to ACL

- posterior horn behind tibial eminence

- ligaments of Humphrey and Wrisberg are attached to posterior horn

- popliteal hiatus posteriorly

 

Lateral Mensicus NormalKnee Arthroscopy Popliteus

 

Microstructure

 

Circumferential type I collagen fibres

- radial fibres to anchor them

- more random mesh structure at surface

- fibrochondrocytes

 

Blood Supply

 

Development

- entirely vascular at birth

- inner 1/3 avascular by 1 year

- adult blood supply by 10

 

Outer 10 - 25% vascular

- genicular arteries

- perimeniscal capillary plexus

 

Inner 2/3

- nutrition via diffusion

 

Synovial fringe

- femoral and tibial surface

- does not contribute to the meniscal blood supply

 

Nerve supply

 

Similar distribution

- peripheral tears more painful than central tears

- proprioception

 

Function

 

1.  Transmit and distribute forces over plateau

- load sharing flexion > extension

- shock absorbing

 

Total medial meniscectomy

- 100% increase in contact stresses

 

Total lateral meniscectomy

- 200-300% increase in contact stresses

 

2.  Secondary stabilisers

- posterior horn resists anterior translation in flexion

- important in ACL deficient knee

 

Classification

 

1.  Longitudinal Tears

 

Mensical Tear Posterior HornMeniscal Tear Posterior Horn

 

Most common

- vertically oriented tear parallel to edge of meniscus

- usually of posterior part of meniscus

- may occur in either meniscus

- extent varies

 

A.  Incomplete 

- usually inferior surface

- may have been complete then healed

- very common posterior horn lateral meniscus after ACL rupture

 

Knee Arthroscopy Healed Meniscal Tear Undersurface Lateral MeniscusKnee Arthroscopy Healed Meniscal Tear Lateral Meniscus Top Surface

 

B. Complete

 

Mensical tear complete longitudinal

 

C.  Bucket handle 

- displaces into intercondylar notch

- may be central or peripheral

- cause of locked knee

- can damage chondral surface over time

 

Bucket Handle Tear MM displaced anteriorly arthroscopyMeniscus Bucket Handle Flipped Anteriorly

 

Mensicus Locked Lateral Bucket Handle

 

2.  Horizontal Cleavage

 

More common in older patient

- horizontal cleavage plane between superior & inferior surfaces of meniscus

- posterior 1/2 of MM

- mid-segment of LM

 

Meniscus Horizontal Tear

 

3.  Oblique

 

Vertically oriented full-thickness tear 

- runs obliquely from inner edge of meniscus out to body of meniscus

- if base posterior, referred to as posterior oblique tear & vice versa

 

4.  Radial 

 

Vertically oriented full thickness tear 

- extends from inner edge radially to periphery

 

Meniscal Radial Tear

 

Incomplete 

- doesn't extend to periphery

 

Complete 

- extends to periphery

 

Parrot beak tear 

- incomplete radial tear with anterior or posterior extension 

 

5.  Complex

 

Elements of all above

- usually in longstanding meniscal lesions

 

6.  Degenerative

 

Complex tear of degenerative meniscus / usually OA

 

Degenerative Meniscal Tear

 

Blood Supply Classification

 

Red - Red Tears

- peripheral 3 mm

- capsulomeniscal junction

- good blood supply

- both sides vascularised

 

Red - White Tears

- only one side of tear vascularised

 

White - White Tears

- peripheral

- neither side vascularised

 

Symptoms

 

History of injury

- twist with weight bearing

- may not be a specific injury especially in middle-aged patient

 

Swelling usually delayed 6 hours & mild 

- can be chronic from synovial irritation

- may be rapid haemarthrosis with capsular tear

 

Locking

- only with longitudinal tears / bucket handle tear

 

Giving Way

- may occur with other knee disorders

- i.e. loose body, instability, weak quadriceps

 

Signs

 

Effusion

 

Tenderness

- along periphery of meniscus

- along joint line

- pain secondary to synovitis in adjacent capsule

 

McMurray's Test 

- tests menisci posterior to collateral ligaments

- point heel towards meniscus testing

- positive test is palpable or audible snap or click

 

1. Fully flex knee

2. Place leg into full IR -> tests LM

3. Extend to 90°

4. Place leg into full ER -> tests MM

5. Extend to 90°

 

X-ray

 

Standard Knee Series

Exclude SONK / loose bodies / OCD / tumour

 

MRI Classification

 

Stoller 1987 J. Radiol.

 

Grade 0 

- normal homogeneous low signal intensity

 

Grade I 

- globular increase signal in meniscus

- doesn't reach either surface

 

Meniscus MRI Increased Signal

 

Grade II 

- linear increase signal, doesn't reach surface

- myxoid intra-meniscal degeneration / partially healed tear

 

Mensical Tear Incomplete

 

Grade III

- increased signal intensity communicates with meniscal surface

- 70-90% accurate for true tear

- accuracy MM > LM

 

Anterior Horn Meniscal Tear Stoller Grade 3Medial Meniscus Posterior Horn TearMRI Meniscus Tear Posterior Horn

 

MRI Pitfalls / Normal Findings or Variants

 

Ligaments of Wrisberg PMFL & Humphrey AMFL

 

Ligament Wrisberg

 

Transverse Anterior Meniscal Ligament

 

MRI Intermeniscal Ligament

 

Signs of bucket handle tear meniscus

 

1.  Double PCL sign

- medial Meniscus

 

Medial Meniscus Tear Double PCL

 

2.  Absent bow tie sign

- should see bow tie image on 2 consecutive sagittal slices of 5 mm

 

3.  Fragment in notch sign

 

Medial Meniscus Bucket Handle Tear Fragment in Notch

 

4.  Anterior flipped meniscal sign

- torn fragment flips over the anterior horn of the affected meniscus

 

Medial Meniscus Bucket Handle Tear Anterior Flipped MeniscusAnterior Flipped Meniscus Bucket Handle

 

5.  Truncated meniscus

 

Bucket Handle Tear Truncated Meniscus

 

Arthroscopy

 

Mainstay of diagnosis and treatment

 

Bone Scan

 

Don't forget SONK in differential

- 60 yr old female with normal x-rays

- acute onset pain

- AVN MFC

 

Should usually show up on MRI

 

Management

 

Surgical Indications

 

Painful locking / clicking with disability

Acutely locked knee

Repairable meniscus in combination with ACL injury

Repairable meniscal injury in young

 

Options

 

1.  Leave / non operative treatment

2.  Excise

3.  Repair

4.  Meniscal transplant

 

Non Operative Treatment

 

Essentially the asymptomatic patient

 

A.  Stable partial thickness (< 50%)

B.  Stable longitudinal < 1 cm long

C.  Small < 3 mm radial tears

 

ROM exercises + quads drill

Meniscal Transplant

Indications

 

Subtotal Meniscectomy

 

Young patient

- previous total or near total meniscectomy

- developing joint line pain

- early chondral changes

- normal anatomic alignment

- stable or reconstructable knee

 

Contra-indications

 

> Grade 2 Chondral changes

 

Farr et al Am J Sports Med 2007

- combined mensical transplantation with ACI

- improved patient outcomes

 

Aim

 

To prevent progressive cartilage damage

 

Issues

 

1.  Graft selection

- usually fresh frozen

 

2.  Graft sizing

 

Size needs to vary < 5% compared with original

 

Options

- X-rays accurate in 79% cases

- CT scan

- MRI accurate to within 5 mm

 

3.  Surgical technique

 

Secure fixation important

 

Technique

 

Bone in slot techique

- maintain meniscal attachment

- prepare bone graft to fit in 8 mm slot

 

Mensical Graft PreparationMeniscal Graft 2

 

Small medial or lateral parapatella to make trough

- prepare meniscus

- leave margin of meniscus to allow suture to

- mark site with needle

- just on inner margin of articular surface

- mark with shaver

- insert guide pin, drill over, then insert box cutter

- carefully clean out with shaver

 

Mx Transplant Medial ParapatellarMensicus Preparation 1Meniscus Preparation 2

 

Mark Trough 1Mark Trough 2Guide wire for troughPrepared Trough

 

Pass graft

- place suture at junction of body and posterior horn

- make posteromedial approach

- insert graft bone into slot

- secure with screw

- flip meniscus

- secure posterior horn with all inside sutures, body with inside out, anterior horn with outside in

 

Graft PassageGraft Passage 2Inside Out SuturesOutside In Repair

 

Mensical TransplantMensical Transplant Xray

 

Results

 

McCormick et al Am J Sports Med 2014

- 172 patiens, mean age 30 +/- 10 years

- 95% survival at 5 years

- 22% arthroscopic debridement

- 4.7% need revision transplant or TKR

 

 

 

 

 

 

 

 

 

Meniscectomy

Background

 

Meniscectomy 

- resect 30%

- increases contact pressures 3.5 x

- shock absorbing capacity reduced to 20% normal

 

Results of partial & total meniscectomy are very poor in children

- meniscectomy in children is a last resort

- repair amenable tears

- treat others non-operatively

- only real indication for meniscectomy is locked knee not amenable to repair

 

Partial better than total

- less OA and less instability

- excision of unstable or loose meniscus with maximum preservation

 

Types

 

1.  Partial Meniscectomy

- excision unstable fragments that can be pulled into joint

- stable rim / menisco-capsular junction preserved

- smooth rim, but don't need perfectly smooth as remodels

 

2. Sub-total Meniscectomy

- excision of portion of rim usually posterior horn

 

3.  Total Meniscectomy

- required if completely detached and unrepairable

 

Results Meniscectomy

 

Total meniscectomy

 

40% OA at 15 years 

- compared with 6% in normal knee 

 

Meniscectomy Open

 

Partial Meniscectomy

 

1.  No chondral damage at arthroscopy

- 95% good results

 

Schimmer Arthroscopy 1998

- deterioration over time for partial meniscectomy

- 90% good or excellent at 4 years

- 80% good or excellent at 14 years

 

2.  Chondral damage at arthroscopy

- if obvious articular damage initially good or excellent 60% at 12 years

- if grade III or IV good or excellent 10%

 

Technique Excision Bucket Handle Tear

 

Indication

- long standing

- irreparable

 

Technique

1.  98% detachment posterior horn

- scissors / punch

2.  Complete detachment anterior horn 

- can use arthroscopic knife for this portion

- insert through anteromedial portal and cut down

3.  Grasp meniscus firmly with grasper

- roll meniscus several times then twist

- break flimsy posterior attachment

4.  Remove meniscus

- may need to enlarge anteromedial portal

5.  Smooth remaining meniscus with shaver

 

Lateral Meniscus Bucket HandleMensicus Division Posterior HornPost Removal Bucket Handle Meniscus

 

 

 

 

 

 

Results Meniscal Repair

Repair v Meniscectomy

 

Stein et al Am J Sports Med 2010

- follow up of repair v partial meniscectomy for 8 years

- repair group: 96% return to preinjury activity, 20% develop OA

- partial meniscetomy: 50% return to preinjury activity, 50% develop OA

 

Shelbourne et al Am J Sports Med 2003

- repair v partial meniscectomy in ACLR

- equal results in each group

- 90% good outcome in each group

 

Outcome Repair Combined ACL / Meniscal Repair

 

Symptomatic / Clinical Failure and Meniscectomy

 

Kalliakmanis et al Arthroscopy 2008

- 280 meniscal repairs with ACLR with 2 year follow up

- 92% success FasT-Fix based on symptomatic failure / excision

- 86% RapidLoc

 

Toman et al Am J Sports Med 2009

- 77 mensical repairs combined with ACLR

- 96% success rate

- 3/77 (4%) failure at 2 years as defined by symptomatic failure / excision

 

Second Look Arthroscopy

 

Tachibana et al Am J Sports Med 2010

- second look arthroscopy after ACLR and meniscal repair in 46 patients

- 83% patients symptom free

- 74% healed, 15% incompletely healed and 11% failed

- 3/9 incomplete healing had vague knee pain

- 1/7 failed meniscus had symptoms

 

Ahn et al Am J Sports Med 2010

- ACLR + medial meniscus tear in 140 patients

- second look arthroscopy at average 3 years

- 84% complete healing

- 12.1% incomplete healing with no symptoms

- 3.6% (5/77) failed to heal and were failures

 

Feng et al Arthroscopy 2008

- ACLR + BH meniscal repair in 64 patients

- relook arthroscopy

- 90% success rate

- 82% completely healed

- 7.5% incompletely healed with joint line tenderness but otherwise asymptomatic

- 10% failed with locking symptoms (7/64)

- 4/7 failures occured in failed ACLR

 

Outcome Mensical Repair ACL Deficient Knee

 

Steenbrugge et al Int Orthop 2005

- 23 meniscal repair in ACL intact knee v 22 meniscal repair in ACL deficient knee

- 1 failure in the ACL intact group

- 4 failures in the ACL deficient group (18%)

 

Hanks et al Am J Sports Med 1990

- meniscal repair in 22 patients who were ACL deficient

- 3 failures (13%)

 

Outcome Repair Isolated Meniscal Repair in Stable Knee

 

Majewski et al Am J Sports Med 2006

- 88 isolated meniscal repairs in stable knees

- 21 clinical failures requiring partial meniscectomy (24%)

 

Eggli et al Am J Sports Med 1995

- 52 isolated meniscal repairs in ACL stable knee

- follow up 7 years

- 14/52 failed (27%)

- significantly more failures in group with resorbable sutures

 

Bak et al Acta Orthop Scand 1993

- 27 isolated bucket handle tears in ACL stable knees

- failure 10 / 27 (37%)

 

Tear Type

 

Krych et al Am J Sports Med 2010

- medial meniscal repair with ACL reconstruction 18 years or younger

- successful 84% with simple tears

- 57 - 59% success for displaced bucket handle or complex tears

 

Krych et al Am J Sports Med 2008

- isolated meniscal repair in patients 18 years or younger

- successful 80% with simple tears

- successful 68% in displaced bucket handle tears

- 13% complex tear

 

Noyes et al Am J Sports Med 2002

- 71 patients < 20 with complex avascular zone tears in patients

- meticulous inside out vertical repair

- 75% success rate

 

All Inside Implant

 

Seibold et al Arthroscopy 2007

- 113 patients with the meniscal arrow

- combined isolated and meniscal repairs with ACLR

- 28% retear requiring repeat arthroscopy and partial meniscectomy

 

Gifstad et al Am J Sports Med 2006

- 41% failure rate with Biofix Arrow

 

Barber et al Arthroscopy 2006

- success 87.5% with RapidLoc device

 

Barber et al Arthroscopy 2006

- 95% success with Biostinger

 

Kotsovolos et al Am J Sports Med 2006

- 9.8% failure rate with FasT-Fix

 

All Inside v Inside Out

 

Bryant et al Am J Sports Med 2007

- RCT of arrows v inside out suturing

- isolated repair and meniscal repairs with ACLR

- 11% failure rate in each group

- 2 arrows required surgical removal because of subcutaneous position

 

Spindler et al Am J Sports Med 2003

- prospective comparison of arrows v inside out suturing

- all in ACLR

- 88 and 89% success rates in each group

 

Failed Repair

 

Mensicus Failed Repair MRI0001Mensicus Failed Repair MRI0002

 

Miao et al Am J Sports Med 2011

- follow up of 89 repaired meniscal tears

- used arthroscopy as gold standard to see if healed or failed repair

- overall healing rate 86%

- clinical examination limited

- MRI 90% sensitive, but up to 98% specific

 

Re- repair

 

Voloshin et al Am J Sports Med 2003

- re-repair in 14 patients

- 72% survival rate

Miscellaneous

Compartment Syndrome Exertional,

DefinitionCompartment Release

 

Increased pressure within a closed fibro-osseous space

 

Aetiology

 

Seen in athletes, associated with repetitive exertion

 

Anatomy

 

Leg

 

1.  Anterior compartment

- anterior tibial artery

- deep peroneal nerve

 

2.  Lateral compartment

- SPN

 

3.  Superficial posterior

- sural nerve

 

4.  Deep posterior

- posterior tibial nerve

- posterior tibial and peroneal artery

 

Pathophysiology

 

During strenuous exercise, muscle can swell up to 20 x resting size

- 20% increase in volume

- fixed compartment size

- increased pressure / decrease inflow

 

Becomes insufficient to meet metabolic needs

- develop pain

 

Fascial defects

- 40% in exertional compartment syndrome patients

- 5% in normal population

- 1-2 cm 

- junction of anterior and lateral compartments

- often at exit of SPN

- with swelling, fascial edge may compress SPN

 

Incompletely understood phenomenon

 

Affects

 

Anterior compartment > lateral compartment

> deep posterior compartment > tibialis posterior compartment

 

DDx

 

Stress fractures

Muscle strain

Nerve entrapment

Spinal stenosis

 

Symptoms

 

Insidious onset of pain after certain period of exercise

- ache to sharp pain

- predictable and reproducible time and level of exertion

- localised to specific compartment

 

May get transient numbness or weakness in compartment

 

Site is tender at time

- may have concomitant muscle herniation thru fascial defect

- may feel increased tension

 

X-ray

 

Rule out stress fracture

 

Bone Scan

 

May show diffuse uptake along tibia in some cases

- lack of uptake rules out stress fracture

 

Ultrasound

 

Fascial defect with muscle herniation

 

Fascial Defect

 

Compartment Measures

 

Diagnostic

- Too difficult to measure during exercise

- measure before and after exercise

- needle manometry / catheters

- may need ultrasound to accurately insert into deep posterior or tibialis posterior

 

Diagnostic levels

1. > 15 before exercise

2. > 30 1 minute post exercise

3. > 20 after 15 minutes

 

Management

 

Non Operative

 

Reduce activity

- NSAIDs and orthotic shoes

- not often tolerated by athletes

 

Surgical Decompression

 

Compartment Release

 

Compartment

 

Depends on compartment involved

- usually anterior / lateral

 

Open

 

Schmitz et al Int J Sports Med 2004

- open release in 56 patients

- 87% good results

 

Can get wound issues

 

Wound Issue Compartment release

 

Endoscopic

 

Wittstein Am J Sports Med 2010

- endoscopic release in 14 legs in 9 patients

- 8/9 able to resume previous level of sport

- no NV injuries

- haematomas in 2

 

ITB Friction Syndrome

Pathology

 

ITB rubbing on LFC

- long distance runners (slow running more at risk than fast)

- cyclists (seat too high, improper technique)

 

ITB becomes tight, especially posterior portion

 

Develop inflammed tissue under ITB

- synovium

- bursa

 

Aetiology

 

Overuse 

- sudden increase in distance

- hill running

- genu varum 

- improper shoe wear

 

Examination

 

Point tenderness

 

Ober Test 

- unaffected knee and hip at 90o

- abduct hip, flex knee

- if ITB tight, unable to drop below horizontal

 

Investigations

 

Xray / MRI

- exclude other diagnosis

- stress fractures

- ganglion

 

MRI

 

Nishimura et al Skeletal Radiol 1997

- swelling and oedema behind ITB

- usually the posterior portion

- no evidence of thickening of ITB

 

Non operative

 

Physiotherapy

 

NSAID / HCLA injections

- settle the acute phase

- allow aggressive ITB stretching

 

Operative

 

Options

 

1.  Local excision of ellipse / portion of ITB that is catching

2.  ITB lengthening

3.  Excision ITB bursa

 

Results

 

Hariri et al Am J Sports Med 2009

- 11 ITB bursectomies followed up for 20 months

- 9/11 completely or mostly satisfied

 

 

 

 

Knee Cysts & Bursa

Bursas Bakers Cyst

 

12 in total

- 4 anterior

- 4 lateral

- 4 medial

 

Anterior

 

Suprapatellar

Prepatellar

Superficial & Deep Infrapatellar

 

Lateral

 

Biceps femoris - between biceps & LCL

 

LCL - between LCL & capsule over popliteus tendon

 

Lateral Gastrocnemius - between LG & capsule

 

Popliteus - between popliteus tendon & tibia & fibula

 

Medial

 

Pes anserine - between pes & MCL

 

MCL - between MCL & tibia/capsule/SM radiation

 

Semimembranosus - between SM & MG

 

Medial Gastrocnemius - between MG & capsule

 

Popliteal Cyst / Baker's Cyst

 

Semimembranosus bursae or medial gastrocneumius

- can be herniation of synovium through capsule

- increases with fluid in the knee / OA / inflammatory conditions

- one way valve

 

Site

 

In midline and below joint line

- position crucial to avoid confusion with ST tumour

 

Pathology

 

May leak or rupture

- can be very painful

- causes swollen tender calf & mimics DVT

 

MRI

 

Diagnosis

- must communicate with knee joint

 

Baker's Cyst Knee Sagittal MRIBakers Cyst MRI Axial

 

DDx of Popliteal Mass

 

1. Bakers cyst

- transilluminate

- mobile and soft

- medial and distal to flexor crease

 

2. Lipoma

 

3. Aneurysm

- pulsatile

 

4. ST Tumour

- rhabdomyosarcoma / synovial hemangioma / PVNS

- hard, fixed, don't transilluminate, calcification

 

Semimembranosus Bursa 

 

Pathology

 

Enlargement of bursa

- presents betwen semimembranosus & head MG

- occurs in children & young adults

 

Presentation

 

Painless lump behind knee

- inverted U shape

- medial to midline

- most prominent with knee straight

 

Knee joint is normal

- lump may ache

 

Management

 

Usually resolves after 1-2 years

 

Excision should be avoided

- 2/3 communicates with knee

 

Popliteal Cyst in children

 

Very common

- medially, distal to flexor crease

- may be associated with JCA or PVNS

 

Management

 

Resolve over 10-20 months

- 50% recurrence with excision 

- do not operate

 

Prepatellar Bursitis / Housemaid's knee

 

Aetiology

 

Due to friction between skin & patella

- occurs with repetitive kneeling

 

Clinical

 

Circumscribed fluctuant swelling anterior to patella

- knee joint normal

 

Xray

 

May see calcification in long standing cases

 

Prepatella Bursitis Xray

 

Management

 

Rest / knee pad

- may need excision if recurrent & troublesome

 

Infrapatellar Bursitis / Clergyman's knee

 

Bursa Knee Deep Infrapatella

 

Similar to prepatellar bursitis

- swelling superficial to PT 

- more distal

 

Pes Anserinus Bursitis

 

Clinical

 

Occurs over medial upper tibia

- deep to sartorius, gracilis, semiT

- lies between pes anserine & MCL

 

Pain and tenderness over insertion

 

Xray

 

Exclude bony pathology

 

Tibial Osteochondroma with Fracture

 

Biceps Femoris Bursa

 

Related to biceps insertion into fibula head

- may be confused with ganglion from superior tibio-fibular joint

 

 

 

Knee Plica

Aetiology

 

Knee forms from 3 separate compartments

 

Plica represents normal embryonic synovial septum that persists into adult life

 

Epidemiology

 

20% of knees have medial patellar plica at arthroscopy

 

Symptomatic plicae much less common 1-2%

 

Mean age 14

 

Types

 

1.  Infrapatellar (ligamentum mucosum) 

 

Most common / always asymptomatic

 

Role

- likely stabilises the fat pad to the knee

- may prevent fat pad impingement

 

2.  Suprapatellar 

 

Variable

- often incomplete

- may separate suprapatellar bursa from knee

- may hide loose body

 

2.  Medial patellar 

 

Least common / rarely symptomatic

 

Anatomy

- originate from medial wall of knee joint

- run obliquely to insert in medial infrapatellar fat pad

 

Occasionally symptomatic

- gets caught between patella & femur

 

Patient symptoms

- snapping / clicking

- medial pain

- may be able to palpate / reproduce symptoms

 

MRI

 

Medial Parapatella Plica MRI

 

Arthroscopy

 

Normal

- thin

- no evidence inflammation

- no evidence chondral damage

 

Medial Plica Asymptomatic ThinMedial Parapatella Plica Non Pathological

 

Abnormal

- thickened and inflammed

- obvious signs of chondral damage on MFC

 

Medial Plica Arthrscopy Non PathologicalPathological Plica

 

Arthroscopic resection

 

Divide plica to synovial membrane rather than completely excise

 

 

 

 

Knee Scores

ACL / Stability

 

Lysholm

 

Patient based knee score

- limp / support / pain / stability

- locking / swelling / stair climbing / squatting

 

< 65      poor

65 - 83   fair

84 - 90   good

> 90       excellent

 

Tegner

 

Activity score

- score between 0 - 10

- 0 sick leave or disability because of knee problems

- 10 sport at national level

 

IKDC

 

Internation Knee Documentation Committee

- patient based knee score

- activity level / pain / swelling / locking / giving way

- variety of specific activities

 

TKR

 

WOMAC

 

Patient completed

- symptoms

- pain

- functions daily living

 

Knee Society Scores

 

2 Parts

 

A.  Knee score / clinician completed

- pain

- FFD / extension lag / flexion range / alignment / ML instability / AP instability

 

B. Function score / patient completed

- walking

- stairs

- walking aids

 

 

Loose Bodies

Knee Loose Bodies Fragments

 

Source

 

OCD

OA - Osteophytes

Meniscus

 

Symptoms

 

Pain

Locking

Clicking

Can cause chondral damage

 

Xray

 

OA Loose Bodies

 

Loose Body Knee OA MultipleLoose Body Knee OA Small PosteriorLoose Body Knee OA Large Anterior

 

OCD Loose Bodies

 

Loose Body Knee from OCD

 

MRI

 

2 x Osteochondral Fragments in Notch

 

MRI Knee Loose Body In Notch

 

Osteochondral Fragment in PFJ

 

Loose Body Knee MRI PFJLoose Body Knee MRI PFJ Sagittal

 

Loose body in posterolateral compartment

 

Loose Body Posterolateral CompartmentLoose Body Posterolateral Compartment Sagittal

 

Arthroscopy

 

Need to look carefully

 

Common Sites are

 

1.  Notch

- can be covered by soft tissue

 

Knee Loose Body ArthroscopyKnee Arthroscopy Hidden Loose Body

 

2.  Lateral Gutter

- common here

- often need to retrieve via Superolateral portal

 

Loose Body Lateral GutterLoose Body Lateral Gutter Retrieval

 

3.  Posteromedial corner

 

If can't find loose body

- always look here

 

Technique

- put camera in standard portal

- use probe to lift PCL up

- push camera gently into interval between MFC and PCL

- need to make posteromedial portal to retrieve loose body

 

Loose Body Posteromedial RecessLoose Body Posteromedial Recess RetrievalLoose Body Knee

 

4.  Posterolateral corner

 

Technique

- change camera to medial portal

- use probe to lift up ACL

- push camera through

 

Knee Loose Body Posterolateral Corner Arthroscopy

 

5.  Loose body can be adhered and covered in synovium

 

Loose Body Knee Adhered LFCLoose Body Adhered LFC Mobilisation

 

 

Shin Splints

Definition

 

Medial Tibial Stress Syndrome

- pain along the tibial origin of tibialis posterior or soleus

 

Clinical

 

Pain anterior aspect of shin

- running

- soccer

- basketball

 

DDx 

 

Compartment Syndrome

Stress fracture of tibia

 

Mechanism

 

Usually 2° to changes in activity

- increase in mileage

- alteration in terrain

- change of shoes

 

Pain usually follows activity

- gradually intrudes into workout

- eventually precludes activity

 

Xray

 

May show periosteal reaction

 

Management

 

Rest

Achilles stretching

Shock absorbing insoles

Graduated return to running

 

ECSW

 

Moen et al Br J Sports Med 2011

- improved results with ECSW

 

 

 

 

 

OCD

Arthroscopic Mosaicplasty

Case 1: Large Trochlea Lesion

 

Trochlea OCDTrochlea OCD Elevation

 

Trochlea OCD BaseTrochlea OCD Reduction

 

Mosaicplasty Mosaicplasty 2

 

FIxation 1Fixation 2Trochlea OCD Fixation Final

Arthroscopic Treatment

Case 1:  Type 3 Large Unstable MFC OCD

 

MRI

 

Knee OCD Case MRI 1Knee OCD Case MRI 2

 

MRI demonstrates large OCD with fluid completely separating bone on all views

 

Plan

 

Probably unstable

- need to mobilise

- debride base

- bone graft

- fix securely in situe

 

Arthroscopy

 

Knee OCD Case 1Knee OCD Case 2Knee OCD Case 3

 

Knee positioned hanging over edge of bed in knee holder

- usually AL portal

- AM portal made vertical so can be extended to medial parapatella approach

- knee hanging at 90 made acess very easy

- careful and thorough removal of fat pad essential for visualisation

- margins of lesion identified

 

Mobilisation of fragment

 

Knee OCD Case 4Knee OCD Case 6Knee OCD Case 7

 

Lesion carefully mobilised

- left to lever open inferiorly

- want it to stay partially attached

- need to release some fibres of PCL medially

- these are usually all that is holding fragment on

- insert spinal needle from medial to hold fragment open

 

Debride lesion

 

Knee OCD Case 8Knee OCD Case 9Knee OCD Case 10Knee OCD Case 11

 

Fibrous tissue removed meticulously from femur with curette and shaver

- don't microfracture at this point or will bleed too much

- careful debridement of posterior aspect of OCD

- at this point will have 2 - 3 vertical medial portals

 

Take bone graft from medial tibia

- depends on amount of bony defect

- turn into paste / add blood

- put in small syringe that will fit through AM portal

- cut tip off

 

Use K wire to microfracture

- insert bone graft

- immediately reduce fragment

- secure with K wires for cannulated screws

Knee OCD Case 12Knee OCD Case 13Knee OCD Case 14

 

ORIF

 

Knee OCD Case 15Knee OCD Case 16Knee OCD Case 17Knee OCD Case 18

 

In this case, 2 x arthrex bioabsorbably screws used

- drill and tap over wire

- remove wire

- insert screw and bury head

- ensure medial screw not angled into notch

- ensure lateral screw not angled into gutter

 

MRI Follow Up

 

Healed OCD MRI Post ORIF

 

 

 

 

 

Background

DefinitionKnee OCD MRI Cartilage Intact

 

Osteochondritis Dissecans

- separation of avascular fragment of bone & cartilage

 

Epidemiology

 

M : F = 2:1

 

Mean age 18 years

- can present as young as 9

 

4:1000

 

Most common cause of knee loose body

 

There is a genetic predisposition / familial

- can be bilateral

 

Groups

 

2 main groups

 

1.  Juvenile osteochondritis dissecans (JOCD)

- open physes

 

2.  Adult form (AOCD)

- skeletally mature

- may be late presenting juvenile disease

- may be separate entity

 

Aetiology Theories

 

Trauma

 

More important in children

- many children are heavily active in sport

- twisting injury

- instability

- patellar impingement - 80% occur where patella impinges on MFC in full flexion

 

Ischaemia

 

More important in adults

- interruption of blood supply & subsequent AVN

 

Conflicting beliefs

 

Enneking 

- subchondral bone has end arterial arcade much like bowel mesentery 

- prone to ischaemia

 

Rogers and Gladstone 

- rich anastomosis to medullary bone 

- ischaemia very unlikely as cause

 

Pathology

 

Area of subchondral bone undergoes AVN

- overlying cartilage undergoes degenerative changes

 

In young patients, segment often heals

 

In adults, segment usually separates from underlying bone & cartilage

- becomes loose body

- defect may fill with fibrocartilage

 

Location

 

Medial Femoral Condyle 85%

- posterolateral MFC / PCL origin

- can also occur in inferior / central location

- need flexed knee / tunnel view to diagnose

 

Knee OCD Medial Femoral CondyleFemoral OCD

 

Lateral Femoral Condyle 10%

- most common in inferior / central region

- may rarely be anterior

 

Knee OCD Lateral Femur APKnee OCD Lateral OCD

 

Patellofemoral Joint 5%

- often seen associated with patella dislocation

 

Trochlea OCD Post Patella DislocationTrochlea OCD Post Patella DIslocation Sagittal

 

Natural History 

 

Skeletally immature

- spontaneous healing in 50-75%

 

If doesn't heal high incidence of OA in future

 

Symptoms

 

History of trauma in 50%

- symptoms usually vague & poorly localised early

- most common vague ache

 

May be

- locking / giving way / recurrent effusions / joint "mouse"

 

Signs

 

Walk in ER to stop tibial spine impingement on MFC

 

Features of internal derangement

- quads atrophy / effusion / loss of terminal flexion

- localised condyle tenderness 

- palpable loose body

 

Xray

 

Intercondylar view / notch / tunnel view

- most commonly seen in this view

- can miss the lesion unless have flexed knee view 30-50o

 

Knee OCD Xray Type 3Knee OCD Rosenberg View

 

Femoral OCDFemoral OCD 2

 

Findings

- well-circumscribed area of subchondral bone

- separated from MFC by crescentic radiolucent line

- may be empty crater with loose body elsewhere in joint

 

Bone Scan

 

Increased uptake suggests lesion will heal

 

MRI Classification

 

Look for

- integrity of the articular cartilage

- fluid interface (unstable)

- displacement of the lesion

 

1.  Cartilage Intact

- no fluid behind lesion / no breech in cartilage seen

 

Knee OCD MRI Cartilage IntactKnee OCD MRI Cartilage Intact T2

 

2.  Partially detached

- fluid seen partially behind lesion

 

Knee OCD MRI Partially DetachedFemoral OCD Type 3 MRI

 

3.  Completely detached

 

Femoral OCD Type 3 MRIKnee OCD Type 3

 

4.  Displaced

 

A.  Still in relatively normal position

 

MRI Knee Displaced OCDKnee MRI type 4

 

B.  Loose body in knee

 

Knee OCD MRI Displaced and Empty Crater

 

Arthroscopic Classification

 

1. Cartilage Intact 

 

2. Partially detached

 

Femoral OCD Type 2 Arthroscopic

 

3. Completely Detached but insitu

 

Type 3 OCD Femur ArthroscopyOCD Type 3 Arthroscopy

 

4.  Fully Detached with crater & loose body

 

A. Chondral Fragment Salvageable

- recent

 

B. Chondral fragment unsalvageable

- increased in size / change in shape

 

Knee OCD Arthroscopy Fully DetachedKnee OCD Arthroscopy Type 4

 

Type 4 Knee OCD ArthroscopyFemoral OCD Type 4 Non salvageableKnee OCD Fragments

 

Displaced OCD 1Displaced OCD 2Displaced OCD 3

 

Stable v unstable

 

Stable

- cartilage intact

- no synovial fluid behind lesion

 

Unstable

- cartilage not intact

- evidence synovial fluid

 

Other Classifications

 

Site

 

Harding 

- 2 lines

- Blumensaat & posterior femoral cortex

- most lesions between these 2 lines

 

Cahill & Berg Anatomical Classification

- Divide AP into 5 segments

- Divide lateral into 3 from Harding lines

 

Pappas Age Adult vs Juvenile

 

1. Pre-puberty 

- boys 13 years

- girls 11 years

- physis open

 

2. Puberty to 20 years

- physis closing

 

3. > 20 years

- physis closed

 

DDx of Loose Bodies 

 

OCD

OA / Cartilage Fragments

Synovial Chondromatosis

Menisci Tear

ACL Stump

Management

NHx

 

European Orthopaedic Paediatric Study JPO 1999

- 452 patients

- juvenile and adult

 

Findings

- stable lesion with cartilage intact and no dissection had good prognosis

- if signs dissection, surgical management better than non surgical

- sclerosis on x-ray poor prognostic sign

- lesions > 2cm poor prognosis

- 20% OCD in juveniles abnormal x-ray findings at 3 years (not benign process)

 

Non Operative Management

 

Indications

 

1.  Young age < 12

- physis open, good chance of healing

 

2.  Size < 2cm

 

3.  Stable lesion / cartilage intact / no fluid on MRI

 

4.  Hot on bone scan

 

Technique

 

No impact sports

Unloader brace 6/12

Serial MRI at 3/12 and 6/12 looking for healing

 

Operative Management

 

Algorithm

 

Type 1

- stable, no fluid behind lesion

- drill to stimulate blood flow

 

Type 2

- partially detached but stable

- pin in situ

 

Type 3

- completely detached but not displaced

- displace / debride base / bone graft / pin in situ

- screws or mosaicplasty plugs

 

Type 4

- attempt to salvage if piece same size and shape

- otherwise manage chondral defect

- microfracture / MACI / mosaicplasty

 

1.  Drilling in situ

 

Indications

 

Failure non operative management > 3 - 6 /12

MRI no fluid behind lesion

Cartilage intact on arthroscopy

 

Issue

- suitable for stable JOCD

- probably insufficient for AOCD

 

Concept

 

Up to 10 passes

- aim to stimulate vascular ingrowth and subchondral healing

 

Options

 

Antegrade

- easy to do

- violates cartilage

 

Retrograde

- image intensifier or PCL guide

 

Gunton et al CORR 2012

- SR of JOCD treated with retrograde v antegrade drilling

- 86% union v 91% radiographic healing

- no significant difference

 

Antegrade technique

 

Drill through cartilage into lesion

- 1.6 mm K wire

- sufficient depth to penetrate into normal cancellous bone

 

Advantage

- technically easy

 

Disadvantage

- injuring cartilage over lesion

 

Retrograde technique

 

Use II to drill from normal bone into lesion

- technically difficult

- preserves cartilage

 

Femoral OCD Healing Before DrillingFemoral OCD Healing Post DrillingKnee Healed OCD Post Drilling

 

Post operative

 

NWB 6/52 with limitation flexion to 90o

MRI at 3/12 and 6/12

Can start non impact sport at 6/12 if healing - jogging / bicycle

No impact sports 1 year

 

2.  Pin in situ

 

Indications

 

Partially detached lesion

 

Options

- cannulated headless compression screws / metal or bioasorbable

- bioabsorbable smart pins

- mosaicplasty plugs

 

Femoral OCD in situ Femoral OCD K wireFemoral OCD Screw InsertionFemoral OCD Pinned in Situ

 

Post op

 

NWB 6/52

Limit flexion to 90o 6/52

MRI at 3/12 and 6/12 to assess healing

No sport for 1 year

 

Results

 

Din et al JBJS Br 2006

- fixation of JOCD with absorbable screws

- complete union in 12 knees

 

Miura et al Am J Sports Med 2007

- 12 lesions fixated with mosaicplasty plugs JOCD

- complete union on MRI in all cases

- 8 excellent and 3 good outcomes

 

3.  Detach / debride / bone graft / pin in situ

 

Indications

- type 3 lesion

- type 4 / salvageable lesion

 

Options

- open / medial parapatella approach

- arthroscopic

 

Knee OCD Type 3Knee OCD Medial Parapatella ApproachKnee OCD Hinged open & Base drilledKnee OCD Replaced and secured bioabsorbable screws

 

Technique

- critical to debride base to bleeding bone

- must remove any necrotic bone fragments

 

Adult OCD LargeAdult OCD Burr BaseAdult OCD Bleeding Base

 

Adult OCD Necrotic Bone Fragment 1Adult OCD Necrotic Bone Fragment 2

 

Complications

 

Failure of fixation

Non reconstructable

 

OCD Failed FixationOCD Failed Fixation 2

 

Options for large defect, non reconstructable defect 

 

Patella OCS

 

1. Microfracture

 

Knee OCD Fibrocartilage

 

2. Mosaicplasty

 

3.  Autologous chondrocyte implantation

 

4.  Osteochondral Allograft

 

Osteochondral Allograft APOsteochondral Allograft Lateral

 

5. HTO 

- unloads lesion

- use in combination with above procedures if varus malalignment

Mosaicplasty Technique

Harvest site

 

Option 1

- lateral and medial aspect femoral trochlea

 

Option 2

- intercondylar notch

 

Mosaicplasty Harvest Site

 

Option 3

- allograft

- can take larger grafts without donor site risk

 

Size

 

Many options

- 4.5 mm most common

- want to minimise donor site pathology

 

Technique Mosaicplasty Type 3 OCD

 

Mosaicplasty equipment

 

Lateral Femoral OCDLateral Femoral OCD Superior Displacement

 

Harvest

- insert 4.5 mm chisel

- hammer to appropriate depth / 20 mm

- twist handle to remove

 

Mosaicplasty Harvest ChiselMosaic Harvest Site 2Mosaicplasty Harvest Site 2

 

Mosaicplasty PlugsMosaicplasty Plugs 2

 

Mosaicplasty Harvest Site MRI

 

Debride base of OCD and reduce

 

Femoral OCD Base DebridementFemoral OCD ReductionFemoral OCD Reduction 2

 

Drill site of mosaicplasty with 4.5 mm drill

- overdrill 2 - 4 mm

- do not want to leave plug proud

- impossible to sink further or remove

 

Mosaicplasty 4.5 mm drilMosaicplasty 4.5 mm drill 2

 

Insert dilator

 

Insertion device

- place over drill hole

- impact with hammer to seat in cartilage

- insert plug

- use tap to insert plug

- best to countersink 1 - 2 mm

 

Mosaicplasty Plug ImpactionMosaicplasty Cartilage Cap ProudMosaicplasty Impaction

 

Mosaicplasty Plug in situ

 

Repeat

 

Mosaciplasty second plugMosaicplasty Plugs in OCD

 

Post op

 

Often most stable in extension

- splint in extension 2 weeks

- gentle increased ROM in brace over next 4 weeks

- strict NWB 6/52

 

Allow weight bearing at 6/52

- no sports for 6/12

- MRI cartilage sequences at 3 and 6 months to assess cartilage healing

 

Knee OCD Mosaicplasty PreKnee OCD Mosaicplasty 9 months post

 

Mosaicplasty Healed OCD LateralMosaicplasty Healed MRI AP

 

 

 

PCL

Arthroscopic Reconstruction PCL Technique

Aim

- reconstruct anterolateral bundle

 

Graft Options

 

A.  4 strand hamstring / Achilles Allograft

- fixate with 2 x RCI screws for simplicity

 

B.  Achilles Allograft

- bony block for femur

- usually 10 x 20 mm as per normal

- 10 mm ++ tendon length

- don't cut tendon short

- fixate tibial side with screw

 

Set up

- knee at 90 degrees over bolster

- tourniquet

- II required

- need to arrange arthroscopy monitors with II so don't interfere

 

70 degree scope

- to see through notch and down back of tibia

- can use central portal thru patella tendon

 

Posteromedial portal

- under vision

- small triangular soft spot formed by posteromedial edge femoral condyle and tibia

- 1 cm above tibia, 1 cm behind femoral condyle

- above the pes / saphenous nerve and behind MCL

- flex knee to 90 degrees so NV bundles fall posterior

- insert spinal needle first and visualise

- error is too anterior and too low

- need angle down onto back of tibia

- insert 6 or 8 mm cannula

 

Clear tibial origin

- remove soft tissue 

- need adequate visualisation of this area

- chondrotome, electrocautery

- down at least 1 - 2 cm below articular surface

 

Femoral Tunnel

- remember femoral insertion is anterior

- 5 - 8 mm post to articular cartilage margin of MFC 

- 1 o'clock or 11 o'clock 

- don't want it too anterior (avoid AVN, fracture)

- therefore, need to adjust position depending on using smaller HS or larger achilles tendon

- i.e. 7.5 mm tunnel for HS or 10 mm tunnel for achilles tendon

- use PCL jig

- drill outside in

- usually make dissection down medially subvastus

- beath pin should exit halfway between MF epicondyle and Medial patella

- drill tunnel outside in or inside out (surgeon preference)

 

Tibial Tunnel 

- incision medial to tibial tuberosity

- relatively flat tunnel if hamstring, longer if Achilles tendon

- PCL jig inserted

- under fluoroscopy

- Posterior flat spot of the Tibia at lease 1 cm below the articular edge (tibial footprint)

- needs to be more lateral than medial

- curette inserted to protect NV bundle

- knee in flexion to protect NV bundle

- beath pin passed

- ream appropriate tunnel

- can use a device / dacron rasp to smooth out edges

- difficulty passing graft around this tight corner

- AKA killer turn

 

PCL tibial tunnelPCL DrillTibial Tunnel PCL

 

Pass graft / 2 options

 

A.  Up tibial tunnel, around turn and up femoral tunnel

- pass 1 nylon loop with 1 vicryl attached to it down into knee joint from femoral tunnel via beath pin

- pass 1 nylon loop to back of knee via tibial tunnel

- grasp this loop and pull into knee

- pass 1 vicryl through tibial loop, and pull out of tibial tunnel

- can then pull 1 nylon loop down from femoral tunnel

- need to pass dacron rasp first

- repeat and pass graft 

 

B.  Graft pulled into knee via anteromedial portal

- loop nylon / suture passer down femoral tunnel to retrieve femoral end sutures

- loop nylon / bent suture passer up tibial tunnel to retrieve tibal end sutures

- these sutures need to be very lon

- graft sucked into knee joint, ends go separately into the tunnels

 

Fixation

- use 2 x RCI screws for simplicity

- femoral first, screw can be outside in or inside out

- femoral screw 7 x 25 achilles bone block

- tension graft; knee at 90 degrees with anterior drawer

- insert screw

- 9 x 25 - 35 for achilles and hamstring

 

Post-op

 

Full extension for 2-4/52 with PWB

Then PCL brace

Quads rehab

No active flexion for 8/52

Want to avoid flexion past 90 degrees

 

Results

 

Go from 3+ to 2+ in 50%

3+ to 1+ in 50%

 

Avulsion Fracture Technique

 

PCL Bony Avulsion MRI

 

Options

 

Can be done arthroscopically or open

 

Note

 

These can get very stiff

Need to immobilise post operatively

May be best to wait 1 - 2 weeks

- restore preoperative ROM

 

PCL Avulsion 1PCL Avulsion 2PCL Avulsion MRI

 

Open approach

 

Position

- patient prone

- posterior approach to knee 

 

A. Standard Posterior approach to Knee

 

S shaped incision

- lateral proximally to medial distally

 

Superficial dissection

- small saphenous and medial sural midline distally

- open deep fascia

 

Deep dissection

- popliteal fossa

- SM & ST medial, biceps femoris lateral

- medial and lateral gastrocnemius inferiorly

- popliteal artery deep and medial

- vein in middle, tibial nerve lateral

- CPN laterally with biceps 

 

Find and protect medial sural nerve

- track to tibial nerve

 

Identify and ligate middle genicular artery

- allows mobilisation of vessel

- retract neurovascular structures laterally

 

Open Capsule

 

B.  Burk Posterior approach

 

Much simpler

- don't visualise vessels

- interval between ST and medial gastrocnemius

- sweep medial head gastrocnemius laterally

- open capsule

 

Identify PCL with fragment

- helps to identify joint by moving knee

 

Fixation options

- size dependant

- screw / staple, screw with soft tissue wasther

 

Post operatively

- split in extension 6/52

- allow 0 - 30o

 

 

 

Background

Intact PCL

Anatomy

 

Size

 

2 x as strong as ACL

About the same length as ACL 38 mm

 

Cross sectional area 150% of ACL

13 mm diameter (thicker) 

 

Femoral insertion

 

Half moon

- anterolateral aspect MFC

- much more anterior than the origin of ACL                                                                                                       

- 5mm posterior to articular margin on MFC 

- midpoint is 1 cm posterior                                                                                                                   

- 1 or 11 O'clock

 

PCL Arthroscopy

 

Tibial insertion 

 

Bent across post aspect of tibia 

- 1cm below joint line

- inserts onto PCL facet

 

2 Bundles

 

1.  Anterolateral

- most important

- double the size of the posteromedial

- tight in flexion

- try to reconstruct this bundle

 

2.  Posteromedial

- 33%

- tight in extension

 

Menisco-femoral ligaments

 

Both insert to femur with PCL

Originate from posterior horn lateral meniscus

At least one present in > half of all knees

 

Humphrey

- <1/3 diameter of PCL

- anterior

 

Ligament HumphreysLIgament Wrisberg

 

Wrisberg Ligament

- 1/2 diameter of PCL                                                                                                          

 -posterior                                                                                                                                                                                                                

 

Arterial supply

 

Middle genicular artery

 

Nerve Supply

 

Tibial nerve

 

Function

 

Primary restraint to posterior tibial translation

- secondary restraints are PLC

- posterior translation increased even further if PLC and PCL sectioned

 

Secondary restraint to ER and varus
                                                                                                                                                                                                                                                      

Incidence 

 

10x < common ACL

- 3-37% of knee injuries

 

Parolie & Bergfield Am J Sports Med 1986

- 2% of asymptomatic college football players at NFL draft pre-examination

 

Aetiology

 

Direct trauma

- posteriorly directed force on flexed knee

- dashboard injury

 

Indirect

- forced knee hyper-extension

 

Associated Injuries

 

Posterolateral corner

Posteromedial corner

ACL (knee dislocation)

Can be associated with bony fragment (ORIF)

 

Clinical

 

Injury often unremarkable

- knee doesn't feel right

- don't feel pop or tear

- posterior knee pain

 

May complain of difficulties walking down stairs in chronic situation

 

Examination

 

Excessive Recurvatum

 

PCL Deficient Recurvatum

 

Positive Lachman's

 

Need to distinguish between ACL and PCL

 

Posterior Sag

- loss of tibial step off (N 1 cm)

 

PCL Posterior Sag

 

Posterior drawer

 

Restore step off first (tibia 1 cm anterior to femur)

- Grade 1 < 5mm

- Grade 2 < 10

- Grade 3 > 10

 

PCL Deficient Lachmans 1PCL Deficient Lachmans 2

 

Quadriceps Active Test

- patients contracts quadriceps with foot stabilised

- tibia is reduced anteriorly from its subluxed position

 

Exclude Associated Ligament injury

 

PLC instability

 

1.  Posterolateral draw with foot ER

 

2.  Dial test

- patient prone, external rotation

- > 10 - 15o  compared with other side abnormal

- asymmetry 30o PLC only

- asymmetry 30 and 90o, PCL and PLC

 

Dial Test

 

X-ray

 

Bony Avulsion

 

PCL Bony AvulsionPCL Avulsion

 

Posterior subluxation of tibia

 

PCL Deficient Knee Posterior Subluxation Tibia

 

Grade 3 PCL disruption

- posterior tibia subluxed behind posterior aspect femoral condyles

 

MRI 

 

96-100% accurate

 

PCL Femoral AvulsionPCL Midsubstance tear with stretchingComplete PCL Tear

 

PCL Avulsion MRIPCL Posterior Subluxed Tibia

 

Arthroscopy

 

May miss tear as is extra-synovial

 

Pseudo-laxity of ACL 

 

Arthroscopy Torn PCL

 

PCL Tear ArthroscopyPCL Torn Arthroscopy 2

 

 

 

 

 

 

 

                                                                                                          

Double bundle

Achilles Tendon Graft

 

Achilles tendon

 

Tibial bone block

- 8 x 30

- want to be long as secure in anterior aspect of tibia

 

Tendon ends

- divide tendon in two

- 6 mm for anterior aspect

- 8 mm for posterior aspect

- whip stitch

 

Femoral tunnel

 

Anterior 8 mm

Posterior 6 mm

 

Suture passage

 

Suture passer up tibial tunnel

Retrieve into knee

Pass tendon ends into knee joint

Secure tibial end

Reduce tibia

 

Fixation

 

Tibia screw 8 x 25 mm

 

Femur

- line to line

- 6 mm & 8 mm

- ensure screws not too long / into notch

- 25 - 35 mm

- check with depth gauge

 

 

 

LARS PCL Reconstruction Technique

PCL Lars APPCL Lars Lateral

 

Indication

 

1.  Acute < 3/52

- single bundle

 

2.  Chronic

- double bundle

 

Technique Single Bundle

 

Set up

- knee at 90 degrees on bolster

- x-ray getting lateral of knee

 

Tibial tunnel

- lateral arthroscopy portal

- small medial parapatella approach

- insert PCL jig

- has to hook over back of tibia

- medial to ACL

- check position on II

- insert stabilising k wire

- drill 6 mm

- pass loop wire

 

PCL Lars Tibial TunnelPCL Lars Tibial Wire LoopPCL Lars Femoral Drill

 

 

 

Femoral tunnel

- isometric point

- line parallel to blumensaat's

- largest part of femoral condyle

- 40% from anterior aspect

- ensure 1 cm from articular cartilage

- pass wire, drill outside in

- pass loop wire

 

PCL Lars Femoral Drill Entry Point

 

Pass graft

- pass tibial and femoral parts separately

- graft enters via medial parapatella incision

 

Insert Femoral screw

 

Tension

- check tibial step off is reduced

- posterior tibia in line with posterior femur at 90o

 

Management Options

NHx

 

Controversial 

- probably don't do as well as once perceived

- rarely associated with meniscal injury

- usually results in little functional instability

 

Instability / Return to Sport

 

Shelbourne et al Am J Sports Med 1999

- 68 patients with non operative treatment PCL followed up prospectively over 5 years

- average age 25

- 50% sport at same level

- 1/3 sport at lower level

- 1/6 unable to play

- no correlation to degree of laxity

 

Parolie Am J Sports Med 1986

- 25 athletes followed up for 6.2 years

- 84% returned to sports, 68% at same level of performance

- clinical measure of laxity not related to outcome

 

Long Term Outcome / Arthritis

 

Develop PFJ OA

- PFJ OA secondary to increased forces across this joint

- once patient get PFJ OA unable to compensate for posterior instability as quads inhibited

 

Medial compartment OA

- ruptured PCL stops posterior horn medial meniscus acting as a weight bearing structure

- MFC subluxes posteriorly

- tend to get chondral damage over time in some patients

- unable at this time to predict which patients

 

Boynton Am J Sports Medicine 1996

- 38 patients followed up for average 13 years

- 53% medial compartment OA

- 20% lateral compartment OA

- 13% PFJ OA

- some patients did well, others did not

 

Non-operative Management

 

Acute grade I & II  / Intact on MRI / Secondary Restraints intact

 

Protective weight bearing

Splint 2 weeks

Quadriceps rehabilitation +++

Return to sport in 2-4/52

 

Acute grade III / >10mm - no end point / Secondary Restraints intact

 

Exclude other injuries

 

2/52 in extension

- holds tibia reduced / stops tibia subluxing posteriorly

- PCL can heal as is extra-synovial

- don't want it to heal in a stretched position

 

Patient then goes into a PCL brace which also keeps the tibia forward when flexing

- 4/52

- quadriceps drill +++

 

Return to sport in region of 3 - 4 months

 

Operative Management

 

Indications

 

1.  Combined ligamentous injuries

- usually in combination with PLC

- only 1/4 PCL injuries is an isolated injury

 

2.  Displaced avulsion fracture

 

3.  Symptomatic grade III PCL injury

- pain and swelling

- development of PFJ pain / medial pain

- instability

 

4.  ?? Acute grade III injury in athlete

- MRI evidence of tibial / femoral peel off

- consider acute repair

 

PCL Peel off MRI

 

Options

 

1.  Repair bony avulsion

2.  Acute suture repair

3.  Acute augmentation

4.  Reconstruction

 

Repair Bony Avulsion

 

Open

 

Technique

- posterior approach to knee in prone position

- classic posterior approach

- Burk's approach (retract medial head gastrocnemius laterally)

- secure with staple / screw etc depending on fragment size

- see described surgical technique

 

Arthroscopically assisted

 

Technique

 

70o scope

- posteromedial / posterolateral portals

- PCL sutured above fragment and reduced

 

Fixation

- front to back cannulated screws if sufficient size

- hold reduced with wire or sutures through tibia if not

 

Kim et al JBJS Am 2001

- 14 knees with a variety of fixation techniques due to variety in fragment sizes

- patients had PCL avulsion with minimum grade 2 instability

- all knees fixed acutely had no residual stability

 

Acute Suture Repair

 

Indications

- acute Grade 3 in young athlete / active young person

- tibial peel off (posterior approach)

- femoral peel off (anteromedial arthrotomy)

 

Richter Am J Sports Med 1996

- 8 year follow up of 53 patients

- heterogenous group / ACL and PLC injuries included

- both tibial and femoral sided repaired with sutures

- proximal suture repair less laxity than distal

 

Ligament Reconstruction

 

Many patients are left with residual laxity

 

Improves stability by one grade

- no evidence that one graft choice has superior results to another

 

Attempts to improve this outcome

- tibial inlay

- double bundle

 

Kim et al Am J Sports Med 2010

- systematic review of single bundle transtibial reconstruction

- review of 10 studies

- improves stability by 1 grade

- 75% patients resumed normal / near normal activity

- does not prevent OA

 

Issues

- graft choice

- transtibial v tibial inlay

- single v double bundle

 

Graft choice

 

Options

 

1.  BPTB

- potential mismatch is a disadvantage

- need tendon length at least 40 mm

2.  Hamstring

3.  Allograft (achilles)

4.  Artificial

 

Hamstring

 

Chan et al 2006 Arthroscopy 2006

- transtibial 4 strand HS graft

- prospective study of 20 patients

- 16 patients grade 1 laxity, 3 patients grade 2 laxity, 1 patient grade 3 laxity

 

BPTB

 

Hermans et al AJSM 2009

- 22 patients mix of BPTB and HS transtibial

- KT 1000 difference of 2 mm to normal side

- no difference between graft choices

 

Achilles Allograft

 

Ahn et al Am J Sports Med 2006

- 61 patients, transtibial achilles tendon allograft

- group of patients with partial injury to PCL

- PM intact, AL torn

- left PM and reconstructed AL

- theorised may help avoid killer turn

- mean KT 1000 difference 2.7mm

 

LARS Artificial Graft

 

Li et al Int Orthopedics 2008

- retrospective comparison of HS v LARS in chronic PCL

- slighly improved outcomes in term of residual instability in LARS group

 

Transtibial Method

 

Technique

- tunnels in tibia and femur

- pass graft and secure

- can be difficult to pass graft up and around back of tibia and into knee / killer turn

 

Note

- can avoid by passing graft in through knee first

- pass into femoral and tibial tunnel separately via anteromedial incision

- avoids difficulty in passing graft

- only have to pass tibial component around killer turn

 

Advantage

- all arthroscopic

 

Disadvantage

- worry that posterior tibia killer turn can injure graft over time

 

Tibial Inlay Method

 

Technique

- open anatomical placement on graft in tibial trough

- avoids 'killer turn' of graft in tunnel method

- this may contribute to attenuation and stretching of graft over time

 

Evidence

- initial cadaveric studies showed decreased graft attrition and thinning compared with transtibial

- not shown clinically

- does not take into account graft remodelling in vivo

 

Disadvantage

- usually need to turn patient from supine to prone to supine

 

Technique

1.  Drill femoral tunnel and place wire loop into knee

2.  Turn patient prone onto another operating table

- posterior approach to knee

- interval between semitendinosus and medial head gastrocnemius

- incise capsule

- create trough, screw in bone block of achilles allograft

3.  Need to then turn patient back supine

- secure femoral side

 

Results

 

Jung et al JBJS Am 2004

- 12 patients with tibial inlay BPTB graft

- reduced stress radiography from 10 mm average to 3mm posterior displacement

 

Seong and Song Arthroscopy 2006

- retrospective study

- 21 transtibial HS v 22 tibial inlay BTPB

- a couple of grade 2 results in each group

- no significant difference in stability

 

Double bundle

 

Technique

- single tibial tunnel

- 2 femoral tunnels

- use of a Y shaped graft

- AL tensioned at 90o, PM tensioned at 30o

 

No clinical evidence that improves clinical outcome

 

Wang Injury 2004

- compared HS single and double bundles

- no difference between 2 groups

 

PatelloFemoral Joint

Acute Patella Dislocation

Acute Patella DislocationPatella Dislocation Skyline

 

Mechanism

 

1. Direct lateral blow to patella

- usually with knee partly flexed and quadriceps relaxed

 

2.  Indirect low energy injury

 

Epidemiology

 

2 Groups of Patients

 

1.  Patients with no predisposition to patella instability

- traumatic injury

- contact sports

 

2.  Patients with anatomic predisposition to instability

- atraumatic / minimally traumatic injury

- young / valgus malalignment / ligamentous laxity / malrotation

 

Associated injuries 

 

Osteochondral fracture (40-50%)

- LFC or medial facet patella

- patient will have haemarthrosis

- must identify this group, investigate and manage appropriately

 

Pathology

 

Medial Patellofemoral Ligament (MPFL)

- from MFC between femoral epicondyle and adductor tubercle

- to superolateral border patella

- deep to retinaculum / superficial to capsule

 

Usually tears off femur

 

Acts as a checkrein to lateral patella subluxation

- will usually be torn in all patients with patella dislocation

 

Recurrence rate

 

15-20%

- more likely in those predisposed to instability

 

Reduction technique

 

Conscious sedation

- knee extended

- medial force on patella

- usually reduces easily

- splint

 

Examination

 

Haemarthrosis post reduction

- investigate further

 

Xray

 

AP / Lateral / Skyline

- examine carefully for loose body

 

Knee Xray Loose Body

 

CT

 

Shows loose body and origin

 

MRI

 

Demonstrates

- MPFL tear

- cartilage damage

- loose body

 

Patella Dislocation Chondral Damage Medial Facet PatellaPatella Dislocation MRI MPFL Disruption Patella SidePatella Dislocation MRI Loose Body Notch

 

Knee Loose Body PFJPatella DIslocation MRI OCD LFC MPFL Patella Chondral Damage

 

Management

 

Non operative

 

Options

 

1.  First time dislocator with no associated injury

- splint in full extension with lateral patella pad

- reapproximate torn medial structures

- 4 weeks

- then begin VMO exercises +++

 

2.  Recurrent dislocator

- splint only initially for symptom relief

- early ROM and rehabilitation

- no role for long term splintage

 

Operative

 

Indications

- loose body

- management of OCD Lesions

- +/- early MPFL repair

 

Arthroscopy

 

Assess Patella and Femoral Lesions

 

1.  Small pieces cartilage

- remove loose bodies

- microfracture if necessary

 

Patella Dislocation Loose BodyPatella Small Chondral Lesion

 

2.  Large Osteochondral Fragment

- usually medial patella or lateral femur

- open approach to knee

- reduce and fix with bioabsorbable compression screws / pins

 

3.  Large Chondral piece with minimal or no bone

- can attempt suture fixation

- need to warn of risk of failure and need for reoperation

- careful monitoring

 

4.  Large irreparable chondral lesion

- remove loose body

- microfracture / abrasion initially

- if continue to be asymptomatic, consider alternative procedure

- MACI / mosaicplasty

 

Patella Dislocation Unsalvageable Chondral LesionPatella Dislocation Removal Medial Facet Cartilage

 

Early MPFL repair

 

Patella Dislocation MPFL Disruption Patella Arthroscopy

 

Issue

- ? would recurrence rates be reduced with early repair / reconstruction MPFL

 

Results

 

Palmu et al JBJS Am 2008

- RCT of early operative treatment in adolescents < 16

- very high rates of recurrence in both groups (70%)

- up to 50% of this group had contralateral patella problems

 

Silanpaa et al Am J Sports Med 2008

- compared operative and non operative treatment

- all operative patients had arthroscopic repair of medial retinaculum

- equal (20%) redislocation in each group

 

Christiansen et al Arthroscopy 2008

- RCT comparing non operative to open MPFL femoral repair

- redislocation rates the same in each group

 

Camanho et al Arthroscopy 2009

- RCT of operative v non operative

- excluded patients with flat trochlea / valgus > 15o / patella alta

- in surgical group determined if injury on patella side or femoral side

- 7 from patella repaired arthroscopically

- 10 from femur repaired open with anchors

- 0/17 in surgical group redislocated

- 8/16 in surgical group redislocated

 

Problem

 

1.  Can repair MPFL but if anatomically predisposed to instability

- will still redislocate and rerupture MPFL

- exclude valgus / alta / flat patella

 

2.  If attempting early repair, need to address specific MPFL pathology

 

Open Technique

 

Very important to determine if torn from patella or medial epicondyle

- MRI very useful

 

Medical epicondyle avulsion

- over medial epicondyle

- divide deep fascia

- elevate VMO

- identify MPFL

- repair using bone anchors

 

MPFL repair medial epicondyle

 

Arthroscopic technique

 

Pass spinal needle medial to patella

- insert 1 PDS

- retrieve laterally with loop retriever

- repeat multiple times

- mini - incision and tie from outside in

 

 

 

Bipartite Patella

Ossification

 

Patella may develop from one or multiple ossification centres at 3 years

 

Failure of centres to fuse may produce bipartite or tripartite patella

- usually bilateral and painless

 

Classically superolateral

 

Classification Saupe

 

I   Inferior Pole 5%

II  Lateral 20%

III Superolateral 75%

 

Bipartite patella SuperolateralBipartite patella

 

CT

 

Bipartite Patella CT

 

Clinical

 

1.  Overuse

- pain may result from repetitive microtrauma 

- injury to synchondrosis

- point tender & swollen

 

2. Acute injury

- can get acute injury with minor separation

- reports of bipartite patella healing post injury

- check SLR to ensure quadriceps tendon intact

 

Investigation

 

MRI

- confirms quadriceps tendon intact

- look for increased uptake ? symptomatic

 

Bipartite patella MRI

 

Bone scan

- shown to have increased uptake in symptomatic / asymptomatic knees

 

Management 

 

Non operative Management

 

Majority will settle with non operative management

- mmobilisation for 4 weeks

- avoid impact sports

 

Ultrasound / Exogen

- reports of healing bipartite patella post injury

 

Operative Management

 

Options

 

Lateral release

 

Adachi et al Arthroscopy 2002

- lateral release performed

- excellent results in 13 and good in 4

- nearly 2/3 healed and remainder partially healed

- bone union more likely in patients < 15

 

Mori et al Am J Sports Med 1995

- 15/16 united at 8 months post lateral release

 

Removal of bipartite patella

A. Open

- easiest

- often need to reattach quadriceps tendon with anchors

 

B. Arthroscopic

 

Bipartite PatellaBipartite Patella

Chondromalacia Patellae

Definition

 

Patella Chondromalacia

 

Softening and fibrillation of articular cartilage of patella

 

Problem

- softening and fibrillation often seen in asymptomatic population

- can have typical anterior knee pain without retro-patellar changes

 

Epidemiology

 

Female adolescent

- recent increase in activity

 

Query on continuum to OA

May be a separate pathology

 

Aetiology

 

Unknown / varied

 

Mechanical

 

Acute

- direct trauma

- PFJ dislocation

 

Chronic

- PFJ instability

- LPPS (lat patellar pressure syndrome)

- quadriceps imbalance

- VMO weakness

 

Biological

 

Idiopathically abnormal cartilage unable to tolerate load

- inflammatory arthritis

- recurrent haemarthrosis

- sepsis

 

Iatrogenic

- repeated intra-articular steroids

- prolonged immobilisation

 

Degenerative

- primary OA

 

Pathology

 

Basal degeneration of cartilage at deep level

- pain due to nerve endings in subchondral bone being stimulated by variations in pressure

 

Different to pathology of OA

-"Basal Degeneration" compared with surface 

 

Classification

 

Grade 1 

- localised softening with no break in surface

 

Grade 2 

- fibrillation or fissured

 

Patella Fibrillation ArthroscopyPatella Grade 2 Chondromalaciae

 

Grade 3 

- fissuring to bone

- crab meat appearance

 

Patella Grade 3 ArthroscopyChondromalacia Patella Grade 3

 

Grade 4 

- bone exposed / full thickness chondral defect

 

Patella Grade 4 Arthroscopy

 

Symptoms

 

Non-specific

- dull aching discomfort anterior knee

- cinema sign / sitting flexed generates pain

- stairs

- catch & pseudo-locking

- swelling

 

Signs

 

PFJ crepitus

- seen in 60% asymptomatic teens

 

Exclude malalignment

 

Xray

 

Exclude malalignment

 

Management

 

Non-operative

 

NSAIDS

Quadriceps exercises

Activity modification

Cut out brace & taping

Hyaluronic acid injections

 

Operative

 

Options

 

Patellar Shaving

 

Federico et al Am J Sports Med 1997

- arthroscopic shaving in 36 patients with grade 2 or worse

- no malalignment

- all had some improvement

- only 50% good or excellent result

 

Full thickness chondral defect

 

Local Excision & Subchondral Drilling / Abrasion

 

Lateral Release

 

MACI

 

Gobi et al Am J Sports Med 2009

- chondral lesions on patella and trochlea

- all had reasonable symptomatic results

- tended to decline over time in patella and with multiple lesion

 

 

 

 

DDx Anterior Knee Pain

Plica 

 

Jumper's knee / Tendonitis

 

Bursitis

- prepatellar most common

- Pes anserinus 

 

Excessive Lateral Pressure Syndrome / Patella Tilt

 

Hoffa's Disease / Fat Pad Syndrome

 

ITB Syndrome

 

RSD

 

Others

- RA

- Synovial Chondromatosis

- Meniscal tears

- PVNS

- PF Arthritis

- Tumours - hemangiomas 

- Referred Pain - hip / back /ankle

- Cruciate ligament insufficiency / reconstruction

 

Adolescent Knee Pain

 

Bipartite / Multipartite Patella 

 

Sinding Larsen Johannsen

  

Maltracking /alignment 

- ELPL / alta / baja 

 

Osgood-Schlatter's

- local inflammatory around avulsions of apophysis

- self -limiting

- rarely requires surgical management

 

Menelaus-Batten Syndrome

- Johannson- Larsen's disease that affects upper pole patella

- may see fragmentation

 

Hypermobile patella

- ligamentous laxity

 

 

Fat Pad Syndrome

Definition

 

Hoffa's syndrome

- impingement of the fat pad with knee ROM

 

Epidemiology

 

Rare

Diagnosis of exclusion

 

Theory

 

May be more prevalent in patients with intact ligamentum mucosum

 

Diagnosis

 

Hoffa's sign

- apply pressure to fat pad each side of patella tendon with knee in flexion

- extend knee

- will cause impingement

 

HCLA

- behind patella tendon into fat pad

- will relieve pain

 

MRI

 

See increased signal in fat pad

 

Fat Pad Impingement MRIFat Pad Impingement 2

 

 

PFJ OA

EpidemiologyPatella OA Medial Facet

 

1 in 10 patients with symptomatic knees have isolated PFJ OA

 

Aetiology

 

Obesity

Repetitive deep flexion

Malalignment

Lateral patella tightness

Blunt trauma

 

Symptoms

 

Anterior knee pain

- rising from chair

- ascending stairs

 

DDx

 

Plica

Tendonitis

Patella tilt

 

Signs

 

Tender patella

- especially lateral facet

 

Pain with movement PFJ

 

X-ray

 

Laurin View

- assess tilt

 

Patella OA Tilt

 

Merchant view

- assess subluxation

 

Patella OA Subluxation

 

Lateral

 

Patella OA Lateral

 

Arthroscopy

 

PFJ OA ArthroscopyPFJ OA Arthroscopy

 

Patella Grade 4 ArthroscopyPatella Trochela Grade 4 Damage

 

Management

 

Non Operative

 

Medications

- NSAIDS

- glucosamine

 

Cut out braces

 

Exercises 

- hydrotherapy

 

Operative

 

1.  Lateral release

 

Indications

- lateral tilt

- lateral facet OA

- lateral retinacular tightness

- limited goals

 

Patella Tilt Moderate OAPatella Tilt Moderate OA MRI

 

Lateral release

 

Results

 

Aderinto et al Arthroscopy 2002

- retrospective study of 49 patients

- 80% patients felt some reduction in pain

- at 2 - 3 year follow up, 33% very satisfied and 26% satisfied

- 41% unsatisfied

 

2.  TTT

 

A.  Anterior transfer of TT

 

Maquet procedure

 

Elevation of TTT with insertion bone graft

- originally described elevating by 2.5 cm

- problems with skin necrosis / prominence TT / tendonitis

- reduced to only 1 cm and recommended via an anterolateral incision

 

Maquet APMaquet Lateral

 

Results

 

Largely discarded

- causes superior patella tilt

 

Schmid Clin Orthop Related Research 1993

- 35 knees

- 80% good, remainder fair or poor

 

B.  Anteromedial transfer of TT

 

Fulkerson

 

Oblique osteotomy 45˚

- enables antero-medial transfer of tibial tuberosity

- unloads the PFJ and the lateral facet simultaneously

 

Fulkerson Osteotomy APFulkerson Osteotomy Lateral

 

Results

 

Fulkerson et al Am J Sports Med 1990

- 93% good or excellent results in 30 patients at 2 years

- 75% good in 12 patients at 5 years, no excellent

 

3.  Facetectomy

 

Indication

- previous fracture

- isolated OA to one facet

 

Options

- open

- arthroscopic

 

Open procedure

 

Midline incision

- open retinaculum medial or lateral

- excise medial or lateral facet

- leave central ridge to ensure tracking

 

Patella Medial OA post FracturePatella Medial Facet OA Post Fracture Arthroscopy

 

Results

 

Paulos et al Arthroscopy 2008

- arthroscopic lateral release and partial lateral facetectomy

- 80% very satisfied or satisfied

 

4.  Patellectomy

 

Problem

- doesn't completely relieve pain (leaves trochlea)

- extensor weakness and lag / problems with stair descent

 

Technique

- open retinaculum

- excise patella in full

- close retinaculum tightly

- VMO advancement

- this increases strength and decreases lag

 

Patellectomy LateralPatellectomy Skyline

 

5.  PFJR

 

Predates TKR by 10 years

 

Indications

 

Good results in 

- OA from trauma without malalignment

 

Poorer results in OA from unknown cause

- risk developing femoro-tibial OA

- need revision

 

Patient

- isolated PJF OA

- < 60 years old

 

Contra-indications

 

Inflammatory conditions

Patella maltracking and malalignment

Tibiofemoral arthritis / medial or lateral joint pain

 

Malalignment

 

Correct large Q angles preop with TTT

- some correction of maltracking can be obtained intra-op via component positioning and lateral release

 

Failures

 

PF instability

Progressive tibio-femoral degeneration

Loosening rare (< 1%)

 

Types

 

Avon (Stryker)

LCS (Depuy)

 

Results

 

Odumenya et al JBJS Br 2010

- 5 year follow up of 50 patients

- no revisions

 

Ackroyd et al JBJS Br 2007

- 109 patients followed up for 5 years

- survival rate 96%

- 80% good outcomes

- 28% had radiological progression of OA

 

Lonner et al JBJS Am 2006

- revision of 12 PFJR revised to TKR

- for progressive tibio-femoral OA or patella catching / maltracking

- good results

- all PS, no augments or stems required

 

Results Australian Joint Registry

 

7 year revision rate of 22.4%

- males and young age highest risk revision

 

Cause

- progression of disease 35%

- loosening 21%

- pain 11%

 

6.  TKR

 

Patella Baja

Patella Baja

 

Aetiology

 

Congenital

 

Acquired

- trauma

- post ACL reconstruction / TKR

- chronic quadriceps rupture

 

Issues

 

Decreases ROM

Associated with early OA of the PFJ

 

Diagnosis

 

Blackburne-Peel ratio at 30 degrees flexion

 

Patella Baja Blackburne Peele

 

Options

 

Excise lower third patella tendon

Patella tendon reconstruction with achilles tendon allograft

Tibial tubercle osteotomy and proximalization

Patellectomy

 

Proximalization fo the tibial tuberosity

 

Proximalization of Tibial tuberosity 1Proximalization tibial tuberosity 2

 

Patella BajaPost proximalization tibial tuberosity

Patella Fracture

Mechanism

 

Direct blow

- most common

 

Indirect

- forced knee flexion with foot fixed / maximally contracted quadriceps

 

Types

 

1.  Vertical

 

Patella Fracture Vertical

 

2.  Transverse

 

Patella Fracture DisplacedPatella Fracture Displaced AP

 

3.  Burst / Stellate

 

Patella Fracture Stellate

 

Management

 

Non operative

 

Indications

 

Vertical

- biomechanically stable

 

Undisplaced transverse fractures

- < 2mm

- extensor mechanism intact

- able to straight leg raise

 

Patella Fracture TransverseUndisplaced patella fracture

 

Operative

 

Indications

 

Displaced transverse fractures

 

Techniques

 

1.  TBW

 

Patella TBW LateralPatella TBW AP

 

2.  Cerclage wire +/- ORIF

- stellate fractures

 

3.  Lag screws

 

4.  Patellectomy

 

Indications

- unreconstructable fracture

 

Risks

- extension lag / weakness

- anterior instability

 

Gunal et al JBJS Br 1996

- patients with at least 5 fragments

- advocated VMO advancement

- additional medial parapatellar incision

- advance laterally and distally

- demonstrated improved strength and decreased lag

 

Patellectomy Lateral

 

Late Management

 

Malunion Patella Fractures

 

Partial patellectomy

- remove part of medial or lateral facet

- good functional and pain relief

 

Non Union Patella Fragment

 

Patella Fracture nonunionPatella Fracture NonunionPatella Fracture Nonunion CT

 

Patella Fracture Nonunion

 

 

Patella Instability

Background

Definition

Dislocated Patella

 

Repeated dislocation of patella with minimal trauma

- 15-20% of paediatric acute patella dislocations

- more common girls 

- often bilateral

 

Dislocation occurs unexpectedly when quadriceps contracted with knee in flexion 

 

Direction

 

Usually lateral

 

Medial is usually iatrogenic

- excessive lateral release

- lateral release for incorrect reasons

- overtightening of medial structures

 

Anatomy

 

Ossification

 

Usually one ossification centre usually that appears at age 3 & closes soon after puberty

 

Facets

 

Retropatellar surface has 7 facets

- 3 on lateral side

- 1 extra on medial side (odd facet)

 

Patella Medial and Lateral Facets

 

Lateral surface larger than medial

- lateral cartilage thicker than medial

- medial & lateral separated by median ridge 

 

Medial facet & odd facet are separated by another long ridge

 

Tracking

 

Tracking is dynamic 

- lateral in full extension

- more medial & central with flexion

 

Relies on normal static and dynamic stabilisers

 

Static Constraints

 

1.  Bony contours of femur

- prominence of LFC anteriorly

2.  Normal rotational profile

3.  MPFL is constant / static checkrein to patella

 

Dynamic Constraints

 

Quadriceps is dynamic stabilizer

- VMO fibers attach to patella at 65° angle

 

Biomechanics Goodfellow 1976

 

0°         No PF contact

 

20°       Most distal part patella contacts trochlea

 

0-30°    Median patella ridge lies lateral to the centre of the trochlea

 

30-60°  Patella moves medially to be centered in groove

 

60-90°  Deeply engaged in trochlear groove & is held by ST tension

 

90°       Entire articular surface contacts except odd facet

 

>90°    Patella tilts so that medial facet articulates with the MFC

 

135°    Odd facet contacts lateral border of MFC

 

Aetiology Patella Instability

 

Complicated / Multifactorial

 

Valgus malalignment

Ligamentous laxity

Insufficient medial structures (MPFL rupture / medial retinaculum laxity / VMO atrophy)

Tight lateral retinaculum

Trochlea dysplasia

Patella alta

Abnormal rotational profile (femoral anteversion / external tibial torsion)

 

Bony

- patella alta / baja

- trochlea / patella hypoplasia / dysplasia 

 

Soft tissue

- VMO atrophy / medial retinaculum laxity / torn MPFL

- tight lateral structures (capsule, retinaculum, ITB)

- ligamentous laxity

 

Alignment

- femoral anteversion

- external tibial torsion

- genu valgum

 

History

 

Pain 

 

Beware unrelenting pain

- chondral damage

- patella tilt / lateral patella syndrome

 

Instability

 

Traumatic vs. atraumatic onset

Direction of instability 

Age first dislocation

Subsequent dislocations

- mechanism, frequency

- ? voluntar

Treatment to date 

 

Effusions

 

Examination

 

Generalised ligamentous laxity  

 

Wynne-Davies Criteria

- positive if 3 of 5 bilateral signs

- hyperextension of the MCP joints parallel to  forearm 

- touch thumb passively to forearm

- elbows hyperextend beyond 0o

- knees hyperextend beyond 0o

- ankle DF > 45o

 

Patient Standing

 

Valgus Malalignment

 

Patella

 

1.  Squinting patella

- with femoral anteversion patellae point inwards when standing

 

2.  Grasshopper eyes

- patella sits high & lateral due to patella alta

 

Gait

 

In toeing

- internally rotated foot progression angle

- indicates femoral anteversion / tibial torsion

 

Patella Tracking

 

Patient sitting over side of bed

- flex and extend knee

- compare normal to abnormal side (if not bilateral)

 

J-sign

- lateral subluxation of patella as knee approaches full extension

- patella sharply deviates laterally in terminal extension 

- indicates some degree of mal-tracking

 

Patella J Tracking Enlocated in FlexionPatella J Tracking Extension

 

Knee Examination

 

Previous incisions

VMO wasting

Effusion

ROM

- exclude extensive mechanism tightness

- symmetrical heels to buttocks

 

Knee extended (3)

 

1.  Tenderness

- lateral retinaculum 

- retropatellar space

- Bassett's sign (tender medial epicondyle / acute MPFL avulsion)

 

2.  Clarke's Test / patella grind

- produces anterior knee pain with PFJ pathology

- compress patella and ask patient to contract quads

- very non specific test

 

3.  Patellar tilt test

 

Patella Tilt 1Patella TIlt Normal

 

Evaluates tension of lateral restraint 

- patient supine and relaxed with knees extended 

- examiner's thumb on lateral aspect of patella

- lateral edge of patella elevated from the lateral condyle and medial edge depressed 

 

Abnormal if unable to tilt lateral patella to horizontal

 

Knee flexed 30o over pillow (3)

 

1.  Q (quadriceps) angle 

 

Patella Instability Increased Q Angle

 

Measurement

- line from ASIS to centre of patella 

- line from centre of patella to tibial tuberosity

- angle subtended is Q angle 

 

Values

- normal 10o men, 15o women

- abnormal if > 15o in males and > 20o in females 

 

Causes increased Q angle

- femoral anteversion (squinting patellae) 

- external tibial torsion

- lateral tibial tuberosity

- genu valgum 

 

2.  Sage mobility

 

Test at 30o flexion

- move patella medially and laterally

- graded in number of quadrants patella displaces 

- > 50% displacement = insufficient restraints 

 

Patella Lateral HypermobilityPatella Medial Hypermobility

 

Lateral glide 

- >3 quadrants suggests incompetent med restraints 

 

Medial glide

- > 3 suggests incompetent lateral restraint / hypermobile patella

- < 1 suggests tight lateral retinaculum

 

3.  Apprehension test (Fairbank)

 

Patient supine and relaxed 

- place relaxed knee at 30 degrees & push patella laterally as flex

- can also do with knee flexed over edge of bed

- positive test is a quads contraction & apprehension

 

Rotational Profile

 

Prone

 

1.  Lateral border of feet

- if curved, metatarsus adductus 

 

2.   External tibial torsion

- intermalleolar axis > 30o

- Thigh foot angle > 15o

 

Thigh Foot Angle 20 DegreesThigh Foot Angle 35 Degrees

 

3.  Femoral anteversion

- IR > 45o

- Gage's trochanteric angle > 15 - 20o

 

Increased Femoral Anteversion

 

Investigation

AP / Long Leg Views

 

Quantify Valgus Malalignment

 

Patella Instability Long Leg Views Valgus MalalignmentValgus Knee

 

Lateral Xray

 

1.  Assess Patella Alta

 

30o flexion

 

A.  Blumensaat's line / Inaccurate

 

Knee flexed to 30o

- line should just touch inferior pole of patella

- pole above line - alta

- pole below line - baja

 

Patella Height Normal Blumensaat's LinePatella Alta Blumensaat's LinePatella Alta Blumensaat's Line

 

B.  Blackburn-Peele ratio / Best and Most accurate

 

Distance between tibial and patella articular surface

- divided by patella articular surface

- patella alta > 1

 

Patella Baja Blackburn PeelePatella Alta Blackburn Peele

 

C.  Insall ratio

- less accurate, probably because more difficult to measure

- ratios also difficult to remember and calculate

- length of patella tendon v length patella

- patella alta LT : LP 1.2

- patella baja LT : LP <1

 

Patella Height Normal Insall RatioPatella Alta Insall Ratio

 

2.  Assess Trochlea Dysplasia

 

Dejour Crossover Sign

- lateral x-ray at 30o with condyles superimposed

- identify base of trochlea

 

Normal

- clearly defined trochlea groove

 

Trochlea Anatomy NormalTrochlea Normal Anatomy Diagram

 

Abnormal / Crossover

- line of floor of trochlea crosses lateral lip of condyle

- indicates trochlea is deficient proximally

 

Trochlea Crossover

 

Trochlea depth

- < 8 mm shallow

 

Dejour grading system 1 - IV

 

Patellofemoral view

 

1.  Skyline view

 

Technique

- 45o

- shoot throught film

 

Look for

- OCD

- bony avulsion MPFL

 

MPFL Bony Avulsion

 

2.  Laurin view / patella tilt

 

Technique

- knee 20o, camera at bottom

 

Assessment patella tilt

- first line anterior aspect both condyles

- line lateral facet

- should diverge laterally

 

Patella tilt

- lines parallel or open medially

 

Patella Laurin View NormalPatella Tilt Laurin ViewPatella Tilt

 

3.  Merchant view / patella subluxation

 

Technique

- 40o flexion, beam from top

- patella should be well engaged

- central ridge should lie at or medial to bisector of the trochlea groove

 

Congruence angle

- draw sulcus angle

- bisector of sulcus angle

- line to central ridge of patella

- should be - 10o (i.e. medial)

- lateral direction is positive

 

Normal

 

Patella non SubluxedPatella Medial Congruence Angle

 

Subluxed

 

Patella Lateral SubluxationPatella Lateral Congruence AnglePatella Subluxation

 

4.  Trochlea dysplasia

 

Normal

 

Patella Normal TrochleaPFJ Normal Sulcus Angle

 

Sulcus angle

- > 140o flattened

 

Trochlea Dysplasia

 

5. Excessive Lateral Pressure Syndrome

 

Ficat and Hungerford

 

A.  Indirect signs of excessive lateral pressure

- thickened subchondral plate

- increased density lateral facet

- lateralisation of trochlea

- medial facet osteoporosis

- hypoplasia lateral condyle

 

Patella Excessive Lateral Pressure 1Patella Excessive Lateral Pressure 2

 

B.  Indirect signs of excessive lateral ligament tension

- fibrosis lateral retinaculum

- calcification lateral retinaculum

- lateral osteophyte

- bipartite patella

- lateral facet hypoplasia

- medial compartment hypoplasia

 

Patella Excessive Lateral TensionPatella Excessive Lateral Pressure

 

CT

 

1.  Skyline View

 

Assess for

- lateral tilt

- subluxation

- trochlea dysplasia

 

PFJ Axial CT

 

2.  Lateralisation of tibial tuberosity

 

TTTG CT

 

Jones et al Skeletal Radiology

 

Superimpose 2 axial slices

 

A.  Axial slice of trochlea

- line of posterior condyles

- line perpendicular through trochlea

 

Axial CT PFJ

 

B.  Slice through tibial tuberosity

- perpendicular line through TT

 

CT Axial Tibial Tuberosity

 

Calculate Distance between two points / TTTG

 

10 - 15 mm normal, > 15 abnormal

 

Pandit et al Int Orthop 2011

- normal 10 +/-1 on MRI

 

MRI

 

Articular Cartilage Damage

MPFL integrity

OCD

Loose Bodies

 

Arthroscopy

 

Assess chondral surfaces

Removal of Loose Bodies

Tracking

- not particularly valid

- patient is relaxed / knee filled with fluid

Management

Non-operativePatella Instability MPFL and TTT AP

 

Results

 

90% respond 

- very important

- 6 - 12 months minimum before offering surgery

 

Physiotherapy

 

1.  Stretches

- quads stretches

- ITB

- lateral retinaculum

 

2.  Quads strengthening

- avoid pain

- PFJ contact pressures lowest from 0-30o

- short arc quads extension

- closed chain VMO exercises

 

3.  Taping / bracing

- patella cut out brace

- little hard evidence

- may provide proprioceptive feedback

 

Operative

 

Indications

 

For failure of non-operative treatment 

- patella tilt with lateral patella pain

- recurrent instability

 

Options

 

Depends on pathology

- assessment and investigation critical for deciding treatment

 

1.  Isolated Patella tilt

 

Indications

- clinical and xray patella tilt

- no instability / malalignment

- excessive lateral pressure syndrome

 

Techniques

 

1.  Arthroscopic lateral release

- knee in extension

- camera in AM portal

- hook diathermy in AL portal

- 5mm lateral to patella / 1cm superior to patella / down to anterolateral portal

- release retinaculum under vision

- must ensure SLGA coagulated / can visualise

- let down tourniquet at end of procedure

- ensure can evert patella 90o at end

 

2.  Smiley knife release

- arthroscopy

- insert in AL portal

- divide retinaculum by feel

 

Post op

- drain 24 hours

- protect for 1 week

 

Results

 

McGinty et al Clin Orthop 1981

- 32/39 G/E results

 

Complications

 

A.  Haemarthrosis

- can be major / problematic

- insert drain, splint and minimise activities first few weeks

- manage via early washout / insertion drain

 

B. Medial subluxation

- extending release too far into VL

- performing lateral release when have ligamentous laxity and instability

 

Patella subluxation / recurrent dislocation

 

Issues

- must have had long non operative period

- treatment depends on cause

- different treatment options in skeletally immature

 

Treatment algorithm

 

1.  Recurrent subluxation + normal alignment (TTTG < 15 - 20)

- lateral release (only do if patella tilt / tight laterally or will dislocate medially)

- MPFL reconstruction / VMO advancement / medial reefing

 

2.  Recurrent subluxation + malalignment (TTTG > 20)

- above + add TTT (tibial tuberosity transfer)

- Roux-Goldthwaite instead of TTT if physis open

 

3.  Above + Excessive femoral anteversion

- consider DRFO (derotation femoral osteotomy)

 

4. Above + Excessive external tibial torsion (> 45 degrees)

- consider tibial derotation osteotomy

 

5.  Trochlea dysplasia

- trochleoplasty

 

5.  Patella alta

- distalise TT

 

Surgical Algorithm

 

1.  Perform lateral release

- rarely needed

- most patients are ligamentous lax / hypermobile patella

- may be needed in chronic setting or if congenital

 

2.  Perform TTT (if TTTG > 20)

- incision over TTT

- medialise at least 1 cm

- ensure some element of Fulkerson / anteriorise

- can distalise if patella alta

- secure with screws (2 x small fragment usually sufficient)

- reassess stability

 

3.  MPFL reconstruction (with TTT, or if TTTG < 20)

- acts as checkrein to lateral displacement

- usually harvest hamstring autograft

- medial incision

- beware overtightening (will give pain) / patella fracture (drill holes in patella)

- reassess for stability

 

4.  Lateral Trochlea Elevation

- still unstable after above operations

- small lateral incision

- beware fracturing lateral femoral condyle

- need to be able to take bone graft from iliac crest

 

Tibial Tuberosity Transfer

 

Contraindication

 

Open Physis

 

Theory

 

A. Medial displacement corrects Q angle

- must correct Q angle < 10o

- at least 1 cm

 

B. Anterior displacement unloads PJF

 

C. Distal displacement corrects patella alta

 

Types

 

Hauser distalisation

- for patella alta

- operation in isolation had disappointing results

- get posteriorisation tubercle and increased forces across PFJ

 

Fulkerson

- anteromedial transfer

- osteotomy lateral to medial

- direct osteotomy anteriorly

- unloads PJF

 

Fulkerson Osteotomy APFulkerson Osteotomy LateralFulkerson Osteotomy Skyline

 

Elmslie-Trillat

- medialisation

- no posterisation

 

Surgical Technique of TTT

 

Technique 1

- direct osteotomy with oscillating saw lateral to medial

- initial incision slightly lateral of midline over Tibial tuberosity

- lateral incision in periosteum

- osteotomy 1.5 cm deep, 6 cm long

- angle osteotomy 45 degrees / use k wires to guide

- attempt to leave medial and distal periosteum intact for stability

- minimum medial transfer is 1 cm, usually 18 - 20 mm

- fix with two screws

- if want to distalise for patella alta, performing distal step cut, and distalise 6 mm

- never make transfer posterior

 

Tibial Tuberosity Transfer

 

Technique 2

- use reciprocating saw

- cut down from the top, behind the PT

- 4 cm long

- leave intact distally

- use 3.5 mm drill to perforate distal attachment laterally

- can then swing the TT medially on distal / medial pivot

- secure with singe 4.5 mm bi-cortical lag screw

 

Consider patella cartilage

- combine with cartilage procedure

- microfracture / MACI / de novo

 

Patella instability cartilage loss

 

Results

 

Caton and Dejour Int Orthop 2010

- TTT in 61 knees

- 76.8% stability

 

Cossey et al Knee 2005

- 19 patients with TTT / MPFL reconstruction

- no redislocations

 

Skeletally Immature

 

Roux-Goldthwaite

 

Indications

- skeletally immature with malalignment

 

Technique

- lateral half PT rerouted

- under medial PT

- stitched to MCL / sartorius

 

Technique Modification

 

Take medial half patella tendon

- suture to MCL

 

PT transfer + MPFL

- incision midway between PT and MCL

- identify patella tendon

- divide in two

- sharp dissection of medial half off bone

- dissect medially

- divide fascia and retinaculum to expose MCL

- suture to MCL with 2.0 non absorbable sutures

- through same incision can harvest hamstrings for MPFL reconstruction

 

Results

 

Fondren et al JBJS Am 1985

- 43/47 G/E results

 

Medial Operations

 

1.  MPFL reconstruction

 

Indication

- patient with history initial traumatic dislocation

- also indicated in patient with laxity to act as a check rein

 

Grafts

 

1.  Y Graft

- double ST autograft into Y

 

2.  Single limb free semitendinosus autograft

- limb to patella via endobutton

 

MPFL Reconstruction 1MPFL Reconstruction 2

 

Schottle's Point

 

Schottle AJSM 2007

- cadaveric study

- 1 mm anterior posterior cortex

- 2 mm distal to MFC origin

- above blumensaats

 

Schottles Point

 

Technique

 

A. Patella fixation

- incision along medial patella

- 2 drill holes in patella

- attach ends of graft, pass into patella, secure with anchor of choice

- pass graft superficial to capsule

 

B. Femoral fixaiton

- best to use II to find point

- stem between medial epicondyle and adductor tubercle

- Schottle's Point

- drill wire across femur, drill hole for fixation screw

- pass doubled graft into tunnel

- set at 30o flexion

- ensure doesn't dislocation laterallly

- don't overtighten

- secure with screw

 

Xrays 1

 

Tunnel too anterior / tight in flexion

 

Patella Instability MPFL and TTTPatella Instability MPFL and TTT Lateral

 

Xray 2

 

Finding Schottles Point

 

Schottles pointFemoral Fixaiton MPFL

 

Results

 

Nomura et al J Arthroscopy 2006

- recurrent dislocation, no malalignment

- 83% G/E results

- no redislocation at  2 year follow up

 

Howells JBJB Br 2012

- 211 procedures in 193 knees

- all TTTG < 18

- most moderate trochlea dysplasia

- no redislocations at 16 months

 

Shah et al AJSM 2012

- Systematic review MPFL

- 26% complication rate

- 4/629 (0.6%) fractures

- 26/629 (4%) stiffness

- 23/629 (3.7%) failure rate

 

2.  Medial imbrication

 

Indications

- MPFL needs to be intact or won't work

- laxity / stretched / attenuated structures

 

Technique

 

Insall procedure

- medial flap sutured 1 cm over lateral flap

 

Results

 

Scuderi et al JBJS Am 1988

- combined with lateral release

- normal and abnormal Q angle

- 42/52 G/E 81%

 

Barber et al Arthroscopy 2008

- TTT + medical plication in 34 knees

- 91.4% stability

 

Zhao AJSM 2012

- RCT MPFL v medial plicaiton

- 100 patients

- recurrent instability 7% v 16%

- better Kujala scores in MPFL

 

3.  VMO advancement

 

Madigan procedure

- VMO detached and advanced laterally and distally

- sutured to fascia on patella

 

Trochleoplasty

 

Indication

- trochlea dysplasia

- if after MPFL and TTT the patella still unstable at end of case

 

Techniques

 

1. Dejour Trochleoplasty

- lift up anterior aspect femoral condyles

- deepening of trochlea

- replacement of LFC

- risk of chondral fracture / AVN / non union / displacement

 

Utting et al JBJS Br 2008

- 50/54 92% 

- combined with other procedures as required

 

2.  Elevate lateral edge of lateral femoral condyle

- insert osteotome

- gently elevate without fracturing chondral surface

- insert 2 - 3 mm of iliac crest bone graft

- no need for stabilisation

 

Results

 

Nelitz et al AJSM 2013

- trochleoplasty + MPFL in 26 knees

- no redislocation, no complications

- 96% statisfied

 

Tibial Derotation Osteotomy

 

Indication

- excessive external tibial torsion > 45 degrees

- 1 / 5000 people

 

Tibial Derotation Osteotomy

 

Tibial Derotation OsteotomyTibial Derotation Osteotomy Lateral

 

Results

 

Drexler et al KSSTA 2013

- good outcome for 15/17 knees

 

Chronic Dislocation

 

Chronic Patella Dislocation 1Chronic Patella Dislocation 2Chronic Patella Dislocation

 

Chronic / congenital

- patella subluxed out of joint

- patella alta

- treat with identical principles

- lateral release / TTT / MPFL reconstruction

 

Chronic Patella DislocationChronic Patella DislocationChronic Patella Dislocation 5

Patella Tendon Rupture

Epidemiology

 

Usually occurs in young people

- often previous history of tendonitis ± steroid injections

 

Location

 

Usually at level of inferior pole of patella

- less common at tibial tubercle

- mid-substance ruptures rare

 

Clinical

 

Severe pain

Palpable defect

Extensor deficit / unable to SLR

 

Xray

 

Patella alta / high riding patella

 

Patella Tendon Rupture

 

Distal Pole Patella Fracture

 

Patella Tendon Bony Avulsion

 

MRI

 

In chronic cases may only detect that tendon not attaching to distal pole patella

 

Patella Tendon Tear MRI

 

Acute Management

 

Requires operative repair

 

Technique

 

Problem

- avoid baja caused by overtightening patella tendon

- drape patient in such a way so as to palpate other PT

- compare patella heights at end of case

 

Multiple Bunnell / Krackow Sutures to Patella Tendon

- 2 non absorbable

- drill holes through patella ( 3 - 4)

- pass sutures and tie 

- can augment with box fibrewire

 

Patella Tendon Rupture Post Repair Intraosseous Sutures and Box suturePatella Tendon Rupture MRI Post Repair

 

Can reinforce with box wire loop

- large gauge wire 18G

- drill hole in tibial tuberosity

- transverse drill hole in patella

- pass in square and tie

- protects patella tendon

- problem is will break / irritate / need removal

- only do if concerned re repair

 

Patella Box Wire APPatella Box Wire LateralPatella Box Wire Broken APPatella Box Wire Broken Lateral

 

Test repair at end of case

- should be able to do some limited ROM

 

Patella Tendon AvulsionPatella Tendon ORIF

 

Augmentation

 

1. Semitendinosus autograft

- leave semitendinosus attached distally

- pass through distal pole patella

- reattach to tibia on lateral side

 

2.  Patella tendon Allograft

 

3.  Lars Ligament

 

Chronic Rupture

 

Reconstruction

 

Case: Reconstruction with tendoachilles allograft, bone block in tibia

 

Chronic Patella Tendon Rupture XrayChronic Patella Tendon Rupture MRIPatella Tendon Graft

 

Chronic Patella Tendon Rupture 1Chronic Patella Tendon Rupture 2Chronic Patella Tendon Rupture 3

 

Chronic Patella Tendon Rupture 4Chronic Patella Tendon Rupture 5

 

Chronic Patella Tendon Rupture Post Op LateralChronic Patella Tendon Rupture Post OP AP

 

Case: Reconstruction with Hamstring Autograft

 

Chronic patella tendon ruptureChronic patella tendon rupture Hamstring ReconChronic patella tendon rupture Hamstring Recon

 

Chronic patella tendon rupture Hamstring ReconChronic patella tendon rupture Hamstring ReconChronic patella tendon rupture Hamstring Recon

 

Chronic patella tendon rupture Hamstring ReconChronic patella tendon rupture Hamstring Recon

 

Patellar tendonitis

Definition

 

Patellar Tendinitis

 

Epidemiology

 

Most common in athletes

- especially if involved in running, jumping and kicking

- over use injury

 

Basketball players

 

Aetiology

 

Chronic overload v inferior patella impingement

 

Schmidt et al Am J Sports Med

- dynamic MRI in patients with jumper's knee v controls

- no evidence of impingemnt

- concluded that chronic overload main cause

 

Incidence of inferior patella spurs

- likely part of pathology

 

Clinical Features

 

Insidious onset of pain at inferior pole of patella

- initially after activity only, worse as cools down

- localised tenderness at inferior pole

- may progress to rupture

 

X-ray

 

Usually normal

 

May see

- traction spurs

- calcification of patella tendon

 

Patella Tendon CalcificationPatella Spur

 

MRI

 

Cyst / Degeneration

 

Jumpers Knee MRI

 

Traction spurs / calcification / ossicles

 

Patella Tendonitis Calcification MRIPatella Tendon Calcification MRIPatella Spur MRI

 

Non-operative

 

Activity modification

 

Rest 6/52

- warm up & stretching

- ice & NSAIDS

 

Sport rehabilitation protocol

 

Concentration on eccentric exercises

- decline squats on a 25o decline board

 

Jonsson et al B J Sports Med 2005

- RCT of concentric v eccentric quads exercises

- superior results with eccentric

 

Engebretsen et al JBJS Am 2206

- RCT of eccentric rehab v surgery

- no advantage surgery

- recommended minimum 12 weeks non operative treatment in all cases

 

HCLA

 

Contra-indicated

 

Platelet Rich Plasma

 

Fillardo et al Int Orthop 2010

- compared three injections PRP 2 weeks apart in 15 chronic patients

- compared wth 16 patients treated with physiotherapy alone

- significant improvements in PRP group

 

Charousset AJSM 2014

- 3 consecutive US guided PRP into tendon defect

- sucess in 21 / 28 athletes

 

ECSW

 

Vulpiani et al J Sports Med Phys Fitness 2007

- 4 sessions every 2 days

- 73% successful in all patients

- 87.5% successful in athletes with return to sport at 6 weeks

 

Operative

 

Indications

 

Fails to resolve & interferes with activity

 

Technique

 

Arthroscopy

 

1.  Resection fat pad

2.  Resection posterior inflammed portion of tendon

3.  Careful burr resection of inferior pole patella

- 1 - 2 mm

- does't affect patella tendon insertion

- removes source of impingement

- likely stimulates healing process

 

Results

 

Lorbach et al Arthroscopy 2008

- arthroscopic debridement inferior pole patella in 20 patients

- 18/20 good or excellent results

 

Pascarella AJSM 2011

- arthroscopic debridement undersurface of tendon / tendinopathy

- excise distal pole

- success in 66 / 73 knees

- RTS by 3 months

 

 

 

 

Quadriceps Rupture

Epidemiology

 

Usually occurs in patients over 60

- due to decreased vascularity & collagen weakness

 

Younger patient on steroids / growth hormone

 

Occasionally occurs in young athlete with excessive contracture

 

Aetiology

 

Often preceded by quadriceps tendinosis

 

Quadriceps Tendinosis MRIQuadriceps Tendinosis 2

 

Location

 

1.  Avulsion of quadriceps tendon from superior patella

2.  Rupture of belly of rectus femoris

3.  Rupture at musclulotendinous junction in athletes

 

Clinical

 

Quadriceps Tendon RuptureQuads Tear

 

Palpable gap in tendon

Haemarthrosis

 

Extensor lag

- function usually good if tear incomplete

 

Extensor Lag

 

Diagnosis can be missed once acute features settle

 

Xray

 

Patella Baja

 

Quadriceps Rupture

 

MRI

 

MRI Chronic Quadriceps RuptureQuads rupture MRI

 

Management

 

Options

 

Incomplete

- immobilise for 4/52 in extension

- then rehabilitate

 

Rectus Femoris Avulsion 1Rectus Femoris Tear 2

 

Complete 

- surgical repair

 

Athlete 

- surgical repair

 

Surgical Technique

 

Position

- patient supine

 

Midline incision

- expose quadriceps

- mobilise tendon / release from subcutaneous tissue

- debride insertion on patella

 

Quads Repair 1Quads Repair 2Quads Repair 3

 

Drill holes in patella

- pass sutures with houston suture passer

- pass large non absorbable suture

- multiple times through tendon

 

Quads Repair 4Quads Repair 5Quads Repair 6

 

Other option

- suture anchors in distal patella

 

Post operative rehab

- keep in extension 6 - 8/52

 

Late presentations / Rerupture

 

Options

- quadriceps turndown

- quadriceps VY advancement

- fascia lata graft

- Lars graft reinforcement

 

Note: Patella Baja with chronic rupture

- patient may develop patella baja

- with chronic injuries / failed injuries

- may need to perform tibial tuberosity osteotomy

 

Failed Quadriceps Repair

 

Tibial Tuberosity OsteotomyTibial Tuberosity Osteotomy 2

 

 

Quads Repair Tibial OsteotomyQuads Repair Tibial Osteotomy 2

 

Revision Quadriceps Repair with Tibial Tuberosity Osteotomy

 

Allograft Reconstruction

 

Chronic Quads TearQuads Recon 1Quads Recon 2

 

Quads Recon 3Quads Recon 5

 

Quads Allograft Final 1Quads Allograft reconstruction 2

 

Tendo-achilles

- flat portion oversewn proximally

- two limbs passed through drill holes in patella

- sewn onto themselves

 

 

Sinding - Larson - Johanssen

Epidemiology

 

Active pre teen boy

- activity related pain

- common in high jumpers

 

Diagnosis

 

Fragmentation / calcification of inferior pole

- repetitive traction injury where PT inserts

- tender at this point

 

Stages 

 

I     Normal

II    Ca inferior pole irregularity

III   Coalesce Ca inferior pole

IV    Incorporation of Ca

 

DDx

 

Patella stress fracture

Sleeve fracture

Type 1 bipartite patella

Jumper's knee in older patient

 

Management

 

Self- limiting 

- symptomatic treatment

- can use cast immobilisation

 

Rarely surgical excision

 

 

 

Postero-Lateral Corner Injury

Acute PLC Background

Anatomy

 

Posterolateral Complex (3 components)

 

Posterolateral complex anatomyPosterolateral corner anatomy 2Posterolateral Corner Anatomy

 

1.  Lateral collateral ligament

 

Lateral epicondyle to superior fibula head

 

MRI Anatomy

- don't see entire length on single MRI

- need 2 or more images

- inserts superior to popliteus

 

LCL MRI Normal Inferior PartLCL Fibular Origin

 

LCL MRI Normal Superior AspectLCL MRI Insertion

 

2.  PCL

 

3.  Deep complex

 

A.  Popliteus tendon


Surgical Anatomy

- origin posterior tibia

- tendon passes through capsule and hiatus in coronary ligament of LM

- inserts on femur distal to LCL

 

Popliteus tendon intra-articular

 

Action

- acts to unlock the knee (ER femur or IR tibia) when flexing from terminal extension

 

MRI Anatomy

- need multiple images to watch coming around

- follow from muscle into tendon

- inserts in sulcus inferior to LCL

 

Popliteus MRIPopliteus Insertion

 

B.  Popliteofibular ligament

 

Surgical anatomy

- posterior fibular head to popliteus tendon

- 90% of people

- quite consistent

 

Action

- acts as check rein to popliteus

- important resistance to varus rotation and posterior translation

 

MRI Anatomy

 

Popliteofibular ligament MRIPopliteofibular MRI

 

C.  Posterolateral capsule

 

+ fabellofibular ligament

+ arcuate ligament

 

These are much more variable

 

LaPrade & Engebretsen Am J Sports Med 2003

 

Anatomy of the posterolateral corner

 

LCL

- insertion is 1.4 mm proximal to epicondyle and 3 mm posterior

- origin is 8 mm posterior to anterior fibular and 25 mm distal to fibula styloid

 

Popliteus

- inserts anterior aspect of popliteal sulcus

- femoral insertion always anterior to LCL

- average 18 mm from LCL insertion on femur

 

Popliteofibular

- anterior and posterior divisions from the popliteus to the posterior fibular

- posterior main division attaches to fibular styloid

 

Layers Lateral Knee (Seebacher)

 

1.  Superficial

- deep fascia of thigh

- ITB, biceps femoris tendon, CPN

 

2.  Middle

- patella retinaculum

 

3.  Deep

- posterolateral capsule with its thickenings

- LCL / Popliteus / Popliteofibular ligament

 

Actions

 

LCL

- 1° lateral stabiliser at 30° flexion

 

2° lateral stabilisers 

 

Dynamic

- ITB

- popliteus

- biceps femoris

 

Static

- popliteal-fibular ligament

- arcuate Ligament

- ACL

 

Tertiary medial stabiliser

- PCL

  

Incidence

 

5% of knee injuries have a component of PLC instability

 

Mechanism

 

Twisting injury 

 

Direct blow to anteromedial side of knee

- often hyperextension injury

 

Associated Injuries

 

PCL

ACL

CPN (10%)

 

History

 

Feeling of ripping

Swelling usually delayed (extra-articular)

 

Often instability with extension

- knee may buckle into hyperextension with weight bearing

- may walk with knee in flexion to maintain stability

 

Instability up and down stairs

 

Patellofemoral symptoms 

- secondary to posterior displacement of tibia

 

Examination

 

Gait / Stance

 

Varus thrust in gait and single leg stance

- due to ER of tibia 

- apparent varus

- flexed attitude to knee

 

LCL

 

Tested in extension & in 30° flexion

- somewhat theoretical because practically impossible to tear LCL in isolation

- usually associated posterolateral corner injury

- isolated LCL uncommon

 

Grade 1

- < 5mm laxity in 30o flexion

- indicates mild sprain of LCL

- up to 1/3 torn

- usually no laxity in extension

 

Grade 2

- 5-10 mm laxity in flexion

- indicates moderate sprain of LCL

- 1/3 to 2/3 torn

- usually no laxity in extension

 

Grade 3

- >10 mm laxity in flexion

- laxity in extension

- indicates complete disruption of LCL

- indicates disruption 2° restraints

 

LCL Instability ValgusLCL Instability Varus

 

PCL 

 

Laxity demonstrated by positive Lachmann

- posterior sag / loss of step off

- posterior drawer

- quadriceps active

 

 

Posterolateral Corner instability  

 

Posterolateral draw

- foot in ER

- apply a posterolateral rotatary force

 

External rotation recurvatum test

- pick up leg via great toe bilaterally

- tibia hyperextends

- tibia externally rotates due to loss of PLC

 

Dial Test 

- increased ER of Tibia >10° other side

- increased at 30o - PLC

- increased at 30o and 90o - PCL + PLC

 

Dial Test Positive at 30 degrees

 

Reverse Pivot Shift (Jacob et al)

- 35% patients positive / check normal knee

- valgus force, foot ER 

- flexion to extension

- reduction of posteriorly subluxed LTC

 

X-ray

 

Often normal

 

Bony avulsion of Fibula Head / Gerdy's tubercle

- LCL / biceps / ITB avulsion

 

LCL Avulsion Fibular HeadLCL Bony Avulsion

 

Lateral joint widening and subluxation

 

Knee PLC Xray Lateral Widening

 

PCL bony avulsion

 

MRI 

 

Anteromedial bone bruise

 

1.  LCL

 

Options

 

A.  Fibular avulsion / potential for direct repair

 

MRI Avulsion Posterolateral Corner Fibula

 

B.  Midsubstance / require reconstruction

 

Knee LCL Midsubstance Tear PLC injury

 

C.  Femoral avulsion / potential for direct repair

 

LCL Femoral Avulsion MRI

 

2.  Popliteus

 

Options

 

A.  Femoral avulsion / potential for direct repair

 

Popliteus Avulsion MRI

 

B.  Midsubstance / require reconstruction

 

Popliteus Musculotendinous Sprain

 

3.  Biceps Femoris

 

Usually avulsed from fibular head

 

MRI LCL and Biceps Fibular Avulsion

 

4.  PCL

 

Options

 

A.  Femoral avulsion / potential for direct repair

 

MRI PCL Femoral Avulsion

 

B.  Tibial avulsion / potential for direct repair

 

C.  Midsubstance / require reconstruction

 

MRI PCL midsubstance

 

5.  Posterior capsule

 

See oedema at posterior tibia on axial MRI

 

6.  ACL / MCL

 

Knee dislocation

 

Acute PLC Management

Principles

 

Early repair < 3/52 better than late repair

 

Scenarios

 

1.  Isolated LCL Injuries 

2.  LCL + Posterolateral Corner

3.  PCL + PLC

4.  ACL + PLC

 

Need to repair / reconstruct

 

1. LCL

2. PL capsule

3. Popliteus

4. Popliteo-fibular ligament

5. PCL

6. ACL

 

Options

 

Repair

Advancement 

Augmentation 

Reconstruction

 

Surgical Algorithm

 

1.  Capsule

- with anchors / staples

- may need to repair lateral meniscus capsular avulsion

 

2.  Popliteus

 

A.  Direct repair of femoral origin

- suture anchors / staple

 

B.  Reconstruct

- musculotendinous junction injury

 

Options

 

ITB

- harvest central third

- leave attached distally

- tubularise

- pass back through drill hole in tibia anterior to posterior

- repair to femoral insertion

 

Lars / Hamstrings / Achilles allograft

- insert into popliteus insertion with interference screw

- pass posterior to anterior in tibia

- secure at 30o

 

3.  Popliteofibular ligament

 

A.  Direct repair of fibular avulsion

- usually attached with LCL to bony fragment

 

B.  Reconstruct

- Laprade Technique with LCL / Popliteus

- see chronic reconstruction

 

4.  LCL

 

A.  Direct repair of avulsion from femur or fibula

- trans-osseous drill holes

- suture anchors

 

B.  Reconstruct midsubstance tear

 

Biceps tendon

- leave attached distally

- pass up under ITB

- attach to epicondyle

 

Semitendinosus / Lars / Achilles Allograft

- attach to femoral insertion with RCI screw

- pass beneath ITB

- pass front to back through fibula

- reattach to femur

- suture two limbs together to tighten

 

LCLLCL graft passed through fibula

 

LCL Recon 2LCL Reconstruction Final

 

LCL ReconstructionLCL Reconstruction Lateral

 

C.  Large Bony Avulsion

 

Fixate with screw into fibular or tibia

 

Repair Fibular Avulsion

 

5.  Biceps Tendon

 

Repair fibular avulsion

- suture anchors to fibular head

- advance to proximal tibia and secure with staples (Shelbourne)

 

Combination injuries

 

1.  Acute PCL + PLC

 

PCL insertion injury

- open repair via medial parapatella incision

- sutures into PCL

- pass beath pins into insertion on MFC

- medial approach to distal femur, elevate VMO

- tie sutures over medial femur with endobutton / over cortex

 

PCL midsubstance

- Lars acute repair

- autograft / allograft reconstruction

 

2.  Acute ACL + PLC

 

Reconstruct ACL

 

3.  Acute ACL / PCL / PLC

 

Reconstruct ACL

 

Repair or reconstruct PCL

 

Alternative Management

 

Shelbourne Am J Sports Med 2007

 

Enmass surgical repair of lateral side

- advance tissue (capsule / LCL / biceps / popliteus) to tibia

- don't dissect out individual structures

- pass sutures into tissue

- freshen tibial bone, staple to tibia

 

CPM 0 - 30o overnight

- CPM during first week to 130o

- ROM brace

 

Posterolateral Corner Aute Advancement Plus ACL

 

Results

- only 2 of 17 had 1+ laxity

 

Problem

- doesn't deal with LCL / Popliteus femoral avulsion

 

Rehab

 

Lock in extension 3 weeks

- isometric quads exercises

- 4-8 weeks gentle ROM in ROM brace

- no active hamstrings

- quads exercises

 

Can get very stiff

 

Literature Review

 

Reconstruction v Repair

 

1.  Stannard et al Am J Sports Med 2005

- reconstruction v repair

- reconstruction better outcomes

 

A.  Repair if < 3 weeks and able to

- suture anchor repair LCL to fibula / Popliteus avulsion from femur

- ORIF of femoral bone avulsion

- all other structures repaired as able

- 22 successful, 13 failed (37%)

- good results when able to ORIF fibular head attachments

 

B.  Reconstruction with allograft

- LCL 2 limbs + popliteus

- 20 successful, 2 failed (9%)

 

Problem

- non randomised

- multiligaments included / staged ACLR performed

 

2.  Levy et al Am J Sports Med 2010

 

Multiligament knees

 

A. Repair of injured structures / delayed reconstruction PCL / ALC

- 40% failure

 

B.  Reconstruction (allograft LCL / Popliteus) with PCL / ACL

- 6% failure

 

Problem

- very heterogenous groups

 

 

Chronic PLC Management

Issues

 

1.  Limb alignment

 

2.  Ligament reconstruction

 

Examination

 

LCL

- confirm grade 3 laxity in extension

 

Dial test

- confirm PLC instability

- > 10o compared with other side

 

Increased Dial Test 30 degrees

 

PCL / ACL

 

Xray

 

Stress radiographs useful

- Telos

- confirm PCL / LCL

 

Long leg views

- assess for varus malalignment

 

MRI

 

Chronic proximal avulsion LCL / Popliteus

 

MRI Chronic Posterolateral CornerMRI Chronic Posterolateral Corner Reconstruction 2

 

Chronic distal avulsion LCL

 

LCL Chronic Distal Avulsion MRI

 

Limb alignment

 

Chronic PLC Long leg ViewChronic Posterolateral Corner Mechanical Axis

 

Definition Varus Malalignment

 

Long leg view

- mechanical axis passes medial to tip of medial tibial spine

 

Issue

 

Varus knee alignment and varus thrust in stance phase 

- high rate of soft tissue reconstruction failure in these groups

 

These patients need valgus HTO to correct alignment

- often performed as staged procedure as HTO may relieve instability symptoms

 

Case

 

ACL / Posterolateral corner / patient in varus

 

ACL LCL MRIACL LCL MRI 2

 

ACL PLC AlignmentACL HTO IntraoperativeACL HTO

 

Surgical Technique

 

Opening wedge HTO

- avoids disruption of proximal tibio-fibular joint

- tighten the posterior capsule

- improves varus and external rotation stability

- allows variation of the posterior slope

 

Must be very careful not to overcorrect

 

Problem

- in a standing LL view, the measured femoro-tibial angle is abnormally large

- the joint line is opened up laterally

- with correction the joint line will close with standing

- the amount of valgus obtained will be more than that calculated at surgery

 

Resolution

A.  Subtract the opening angle in the knee joint

B.  Simply measure the alignment of the other limb and calculate correction to normal valgus alignment

 

Results

 

1.  Laprade et al Am J Sports Med 2007

 

OW HTO in chronic PLC

- 21 patients with genu varum and grade 3 PLC insufficiency

- 4/6 with isolated PLC did not require subsequent reconstruction

- 10/14 with multiliament injuries did require subsequent reconstruction

 

Technique

- opening wedge with plate and allograft bone

- correct so that mechanical axis passes through down slope of lateral tibial spine

- decrease posterior tibial slope with ACL deficiency

- increase posterior tibial slope with PCL deficiency

 

Ligament reconstruction

- wait 6/12

- procede if patient remains symptomatic

 

Conclusions

- always do as stage procedure

- may be sufficient in isolated PLC and low velocity injury

 

Posterolateral Corner Reconstruction

 

Important structures

 

LCL (primary varus restraint)

Popliteus (prevents ER)

Popliteofibular (check rein to popliteus)

 

Always reconstruct ACL / PCL at same time

 

Options

 

A.  Central slip of biceps reconstruction LCL

 

B.  Biceps tenodesis

- leave attached to fibular

- advance onto femur

- tightens lateral structure

 

C.  Hughston Arcuate Complex Advancement 

- femoral bone block 12mm?

- has LCL / Popliteus / Arcuate / capsule / lateral head gastrocnemius

- knee in IR and 30o of flexion

- Advance ~ 1cm

- Best if structures can be defined

- good option to tighten structures in an ACL reconstruction with some lateral laxity

 

LaPrade Graft reconstruction

 

1.  LaPrade, Engebretsen Am J Sports Med 2003 31 6

- defined the anatomy of the posterolateral corner

 

LCL

- origin is 8 mm from anterior fibular and 25 mm distal to fibula styloid

- insertion is 1.4 mm proximal to epicondyle and 3 mm posterior

 

Popliteus

- inserts anterior aspect of popliteal sulcus

- 18.5 mm anterior and down from LCL

 

Popliteofibular

- anterior and posterior divisions from the popliteus to the posterior fibular

 

2.  LaPrade, Engebretsen Am J Sports Med 2004 32 6

- describe graft reconstruction

- reconstruct LCL / Popliteus / Popliteofibular

 

Technique

- achilles allograft split in two with 8 x 20 mm bone blocks

- 8 mm tunnels in femoral popliteal and LCL insertion

- use 7 mm screws to secure

- drill 8 mm anterolateral to posteromedial tunnel in proximal fibula

- pass LCL graft from anterior to posterior in fibula, secure with 7 mm screw

- 9 mm anterior to posterior tunnel in tibia (elevate lateral head of grastrocnemius)

- pass popliteal and LCL graft from posterior to anterior
- secure with 8 mm graft

 

Post ACL and Posterolateral Corner ReconstructionLateral Post ACL and Posterolateral Corner Reconstruction

 

PCL + PLC

 

Kim et al Am J Sports Med 2011

- compared double bundle PCL with single bundle PCL

- in association with PLC reconstruction

- 42 patients followed up for minimum 2 years

- no significant difference between the two groups

 

 

Surgical Approach PLC

Surgical Approach to Posterolateral Corner

 

Normally need only part of exposure for any one procedure

 

Position

 

Supine with sandbag under buttock

- knee flexed 90°

- radiolucent table

- II available

 

Incision

 

Landmarks

- Gerdy's tubercle and midpoint femoral condyles

 

Incision

- long curved incision centred over Gerdy's tubercle

- clear subcutaneous fascia down to ITB

 

3 fascial incision

 

PLC Dissection 1PLC Dissection 2

 

1.  Posterior to Biceps

 

Find and protect CPN 

- identify out of zone of injury proximally

- behind biceps

- dissect down to fibular neck

- will be encase in scar / careful dissection

- down into anterior compartment

- identify and protect with vessiloop

 

Elevate lateral head of Gastrocneumius posteriorly

- find posterior aspect of tibia

- popliteus

- posterior capsular avulsions

 

2.  Between biceps and ITB

 

Dissect onto fibular head and proximal tibia

- LCL / biceps fibular head avulsions

 

3.  Bisect ITB

 

Dissect onto epicondyle

- femoral insertion LCL

- femoral insertion popliteus

 

Deep dissection

 

Enter the joint 

- anterior or posterior to lateral ligament

- usually posterior

- posterior capsule covered by lateral head of gastrocnemius

- peel lateral head of gastrocnemius off capsule

- beware lateral superior geniculate artery under gastrocnemius / coagulate

 

Capsule usually torn

- dissection already done

- popliteus inserts into femur by way of intracapsular tendon

- popliteus tendon and muscle may obscure posterolateral capsule

Postero-Medial Corner Injury

Anatomy

 

Layers of the medial knee

 

Layer 1

- sartorius and sartorius fascia

 

Layer 2

- superficial MCL

- posterior oblique ligament

 

Layer 3

- deep MCL (meniscofemoral and meniscotibial ligament)

- posteromedial capsule 

 

MCL

 

Origin

- 3 mm proximal and 5 mm posterior to the epicondyle

 

Insertion

- 6 cm distal to the joint line

 

Xray landmarks

 

Wijdicks et al JBJS Am 2009

- describes radiographic landmarks

- aids reconstruction

 

Management

 

Algorithm

 

Displaced tibial avulsion over pes anserinue

- stener lesion

- requires surgery

 

Avulsed femoral MCL

- reattach / repair

 

Avulsed tibial side

- repair deep meniscotibial ligament with suture anchors

- repair superficial MCL with suture post and ligament washer

- tension at 30 degrees of flexion and varus stress

 

Repair posterior oblique ligament

 

 

Primary TKR

Alignment

Principle

TKR Varus Implant

 

Correct alignment and soft tissue balancing

- two of the most important aspects of successful TKR

 

Technical Goals

 

1.  Restoration of mechanical alignment

- forces of the leg pass through the centre of the hip, knee and ankle

- allows optimal load share through medial and lateral sides of the prosthesis

 

2.  Preservation / restoration of joint line

 

3.  Balanced ligaments

 

4.  Maintaining or restoring normal Q angle

 

Malalignment 

 

Post operative mechanical limb axis within a range of 180 +/- 3o

- associated with lower rates of aseptic loosening

 

Rand and Coventry 1988

- 90% 10 year survival 180 +/- 4o

- 71-73% when deviation > 4o

 

Creates a net varus or valgus moment

- excessive stress on one side of the knee

- excessive wear

- early failure

 

TKR Varus Tibial ImplantTKR Valgus Femoral ImplantVarus TKR early wear

 

Axis

 

1.  Coronal Plane

 

Mechanical Femorotibial axis

- centre of femoral head to medial tibial spine

- medial tibial spine to centre ankle

- should be a straight line 180o +/- 3o

 

Anatomic Femorotibial axis

- anatomic axis of femur and tibia

- should be 6o +/-3o

 

Anatomical Axis Femur (AAF)

- centre of femoral medullary canal to midpoint whiteside's axis

- usually exits at intercondylar notch

- entry point for IM rod of femoral jigo

 

Mechanical Axis Femur (MAF)

- centre of femoral head to centre of knee joint

 

Valgus cut angle

- angle between femoral and mechanical axis

- LL standing AP

- usually between 5 and 7o

- if cut the distal femur at the valgus cut angle, will place the femoral prosthesis mechanically neutral

 

Mechanical AxisAnatomic AxisAnatomic Axis Femur

 

Short patients -  > 7o

Very tall patients - < 5o

 

Anatomical axis Tibia (AAT)

- centre of tibia to proximal joint line

- normally 3o varus

- medial proximal tibial angle 87˚

 

Mechanical Axis Tibial (MAT)

- centre of tibial spines to centre of weight bearing axis of the distal tibia

- usually same as AAT

- except with traumatic or congenital bowing

 

Mechanical Axis TibiaMedial Proximal Tibial AngleProximal Tibial Slope

 

2.  Sagittal Plane

 

Posterior slope

- proximal tibia 10° posterior slope in sagittal plane

- in the knee this is reduced by the menisci

 

3.  Femoral Rotation

 

Preferred rotational alignment of the femur is slight external rotation to the neutral axis

 

2 reasons

 

1.  Restores Q angle and normal patella tracking

 

2.  Balances the flexion gap 

- proximal tibia normally in slight varus of 3o

- the tibial cut is made at 90o

- perpendicular to the mechanical axis

- the distal femoral cut is made 90o to the axis

- these two cuts match up in extension

- to maintain a symmetric flexion gap, the femoral component must be externally rotated by the same amount

- in flexion, the tibia has been ER by 3o to 90

- must do so to the femur

- allows balanced ligaments in flexion

 

Methods of establishing neutral rotational axis of the femur

 

1.  Leo's Line / Whiteside's axis 

- AP axis of the femur

- line running down the centre of the trochlea to the top of the intercondylar notch

- centre of trochlea groove to centre intercondylar notch

- AP cut is made perpendicular to this axis

 

2.  Epicondylar axis 

- only landmark available in revision

- place femoral component parallel to the epicondylar axis

- AP cut is made parallel to this axis

 

3.  Posterior condylar axis

- line connecting bottom of medial and lateral posterior condyles

- AP cut is made in 3o of external rotation to this line

 

Effects Internal rotation Femur

 

1. Unequal flexion extension gaps

- alters relative dimensions of posterior condyles in flexion

- tight medially

- loose laterally

- discomfort 

- limited flexion

- accelerated poly wear

 

2.  Lateral patella tracking

 

3. Anterior medial femoral notching

 

4.  Tibial Rotation

 

Internal rotation of tibial component

- relative external rotation of tibial tubercle

- increase the Q angle

 

Alignment and Resection Methods

 

Most systems use Classic Alignment & Matched Resection 

- cut tibia and femur perpendicular to MA

- ER femur 3°

- balance soft tissues

 

Two alignment methods

 

1.  Classic method alignment

 

Insall

- matching mal-alignments by 3°

- joint lines cut perpendicular to MA

- tibia cut in neutral / over-resect lateral tibial plateau

- femoral cut in 3° varus

 

Problem

- in flexion the lateral flexion gap is too large & trapezoidal

 

Overcome by ER femur 3°

 

2.  Anatomic alignment

 

Technique

- cut 9° to the femoral shaft

- corrects for 3° malalignment in flexion gap 

- have to use in conjunction with Matched Resection Method

 

Two resection methods

 

1.  Matched resection method

 

Technique

1.  Bony resection first

2.  Ligament balancing 

 

Advantage

- avoids problems of excessive bone resection to balance contracted capsule in Flex / Ext Gap Method

- the intact femoral condyles is the distal reference femur

- posterior LFC is the AP Femoral Reference

- preserves the joint line relative to the collaterals 

 

2.  Flexion extension gap resection method

 

Insall

- cut tibia perpendicular to mechanical alignment

- automatically ER femoral component 3° by IR femur 3° with Tensioner in flexion gap

 

Advantage

- again matched mal-alignments 

- usually gives good result if not severe deformity / contracture

 

Problems

A. Capsule contracture causes excessive bone resection

- carefully address this prior 

- post capsule contracture leads to excessive distal femoral resection

- are stable in extension, unstable in flexion

B. Mid flexion instability can result

C. The joint line is not fixed, its position is relative

 

 

Australian Joint Registry 2010

Numbers

 

9 years up to 31 December 2009

- 289 000 TKR

- 80% primary

- 11% primary partial

- 8.5% revision

 

TKR Revision Rate 

 

9 year revision rate of 5.1% OA

- 4.5% in RA

 

Causes

- loosening  30%

- infection   20%

- PFJ           14%

- pain          9%

- instability  5%

 

Risks

- males

- < 55

 

9 year revision by age

 

< 55    11.1%

55-64  6.9%

65-74  4.9%

> 75    2.6%

 

9 year by gender

 

Male      5.7%

Female   4.6%

 

9 year by Bearing

 

Fixed                 4.7%

Mobile Rotating  5.7%

Mobile Slding     6.7%

 

9 year by Constraint

 

Minimal                 4.8%

Posterior Stabilised 6.0%

 

9 year by Patella Resurfacing

 

No Patella  Resurfacing 5.5%

- CR   5.2%

- PS   7.8%

 

Patella Resurfacing  4.4%

- CR 4.3%

- PS  4.6%

 

9 year by Fixation

 

Cemented    5.0%

Cementless  5.2%

Hybrid         4.9%

 

9 year by Cemented Prosthesis

 

Nexgen CR 2.9%

Nexgen LPS     4.4%

PFC                 4.1%

Genesis II        4.5%

Scorpio 5.2%

LCS                 6.0%

 

9 year by cementless prosthesis

 

Nexgen CR       3.7%%

LCS                 5.9%

Advantim         1.5%

 

Primary Patella/Trochlea Resurfacing

 

7 year revision rate of 22.4%

- males and young age highest risk revision

 

Cause

- progression of disease 35%

- loosening 21%

- pain 11%

 

7 year revision by prosthesis

 

Avon 17.9%

 

7 year revision by age

 

< 65  24.6%

 

5 year revision by gender

 

Male 20.7%

Female 13.5%

 

Unicompartmental Knee Replacement

 

9 year revision rate of 13.3%

- young age and females highest risk revison

 

Cause

- loosening 50%

- progression of disease 20%

- pain 12%

 

9 year revision by age

 

< 55    19.7%

55-64  15.6%

65-74  11.1%

> 75    8.8%

 

9 year revision by gender

 

Male 12.1%

Female 14.5%

 

9 year by prosthesis

 

Oxford 3  13.1%

M/G          9.9%

 

Revision TKR

 

Types

- femur + tibia    48%

- tibia only          8%

- femur only        4%

- insert only        13%

- patella only       10%

- patella + insert  7%   

 

Indications

 

Loosening       42%

Infection 18%

Pain                6%

PF pain            6%

Wear tibial       6%

 

7 year revision of revision Uni to TKR

 

Re-revision TKR 17.1%

 

7 year revision of Revision Primary

 

Re-revision TKR 22%

 

 

 

Balancing

Coronal Plane Balancing / Varus Valgus

 

Whiteside's Manual

 

  Medial Structures Lateral Structures
Tight in Extension

Posterior MCL

Semimembranosus

Posterior capsule

Pes Anserinus

ITB

Posterior capsule

Lateral Head GN

 

 

Tight in Flexion

Anterior MCL

PCL

PCL

Popliteus

PL corner

LCL

Principle

 

Release on the concave side of the deformity and fill up on the convex side until the ligament is taut

 

Varus deformity / Medial Release

 

In a severe varus deformity, may be best to PS

 

1.  Removal of osteophytes / meniscus and release deep MCL

- curved osteotome

 

2.  Release posteromedial corner and attachment of semimembranosus 

- denude tibia subperiosteally around to back

 

3.  Release pes anserinus tendons

 

4.  Subperiosteal elevation of superficial MCL at pes anserine region

- cannot release in full

- usually elevate all the tissues as a sleeve

- doesn't require reattachment

- over release: require a constrained knee device / repair and splint in young patient

 

Valgus deformity / Lateral Releases

 

May be best to always PS in valgus knee

 

Order debatable

 

1.  Removal of osteophytes / meniscus and lateral capsule

 

2A.  Tight in extension

- release ITB off Gerdy's tubercle

 

2B.  Tight in flexion

- release popliteus from femur & allow to slide

 

3. Posterolateral capsule

 

4. Lateral head of gastrocnemius off posterior femur

 

5. LCL from femur & allowed to slide

 

2.  Sagittal Plane / Balance Flexion Extension Gap

 

Goal

- obtain a gap in extension equal to the gap in flexion

- will make the tibial insert stable throughout the arc of motion

 

Principle

- more sophisticated and difficult

- the knee has two radii of curvature, one for the PFJ and the other for the weight bearing area of the knee

 

General rule

 

1.  Gap problem is symmetric

- adjust the tibia

 

2.  Gap problem is asymmetric

- adjust the femur

 

6 Scenarios

 

1.  Tight in extension and flexion

 

Problem

- symmetric gap

- did not cut enough tibia

 

Solution

- cut more proximal tibia

 

2.  Loose in extension and flexion

 

Problem

- symmetric gap

- cut too much tibia

 

Solution

1.  Thicker poly insert

2.  Metallic tibial augment

 

2.  Tight in flexion

 

Common in CR / PCL tightness

- limited flexion

- anterior lift off of tibial tray

- tight in flexion

 

Problem

- insufficient posterior femoral cut

- PCL scarred and too tight

- no posterior slope in tibial cut

 

Solution

1.  Clear posterior horns mensicus and posterior osteophytes

2.  Recess / excise PCL

3.  Recut anterior slope of tibia

- maximum 7o posterior slope

4.  Down size femoral component and recut

- increases posterior femoral condyle resection

- avoid notching

 

4. Loose in flexion

 

Problem

- asymmetric gap

- cut too much posterior femur

 

Solution

1.  Upsize femoral component & use posterior femoral augments (cement/metal)

- difficult as not available in primary TKR equipment

2.  Increase poly, convert to tight in extension, recut distal femur

 

5.  Tight in extension

 

Problem

- insufficient distal femoral cut

- tight posterior capsule

 

Solution

1.  Release posterior capsule / osteophytes

2.  Recut distal femur (1-2 mm at a time)

 

6.  Loose in extension

 

Problem

- asymmetric gap

- cut too much distal femur or

- AP size too big

 

Solutions

1.  Distal femoral augments

2.  Increase poly size, convert to tight flexion & downsize femur, convert to symmetric gap problem

 

 

 

 

 

Complications

DVT PE

Natural History

 

Insall 1984 / no prophylaxis

- DVT 70 - 80%

- asymptomatic PE  8 -17%

- symptomatic PE  0.5 -3%

- death  0.2%

- most commonly in calf / 85-90% below trifurcation

 

THR

- THR only 10-15% below trifurcation

 

Bilateral DVT in 10-15%

 

Prophylaxis

 

Mechanical prophylaxis

- TEDS

- compression stockings

- early mobilisation

 

Chemical prophylaxis

- LMWH / enoxaparin

- factor Xa (oral) / rivaroxaban

 

With appropriate prophylaxis

- symptomatic DVT 1/10 or less

- symptomatic PE 1 or 2 / 100

- fatal PE 1 / 1000

 

Results

 

Brookenthal et al J Arthroplasty 2001

- meta-analysis

- LMWH better than warfarin at preventing proximal DVT

- no significant difference in LMWH / warfarin / aspirin in reducing symptomatic or fatal PE

- no significant difference in bleeding rates

 

Edwards et al J Arthroplasty 2008

- RCT of LMWH v LMWH + compression stocking

- significant reduction in DVT rates

 

 

Fractures

Intraoperative Fractures

 

1.  Shaft fracture from IM rod

 

TKR Femoral Shaft Fracture IM Rod

 

2.  Posterior condylar fracture

 

Management

- assess stability

- ORIF if needed

 

TKR Intraoperative condylar fractureTKR Condylar Fracture Lateral

 

Periprosthetic Fractures

 

Definition

 

Within 15 cm of the joint line

Within 5cm of the implant

 

Incidence 

 

Uncommon

- 0.6% primary TKR

- 1.6% revision TKR

 

Most common > 70 / female / revision TKR

 

Mechanism

 

Low velocity fall in elderly osteoporotic patient

 

Associated Factors

 

Patient

- RA

- steroids

- osteopenia

 

Surgical

- revisions

- ? notching

- arthrofibrosis / MUA

- wear / osteolysis

 

Notching

 

Cause

 

1. Posterior referencing and down sizing femur

2.  Internal rotation femur / medial notching

 

Results

 

Ritter et al JBJS Am 2005

- 325 / 1098 (30%) notched femurs with 5 year follow up

- only 2 supracondylar fractures both in femurs that were't notched

 

TKR Femoral NotchingTKR Femoral Notching 2

 

Xray Assessment

 

Fracture location

 

Femur

- proximal to femoral prosthesis

- distal to femoral prosthesis / reduced amount of distal bone for fixation

 

Tibia

 

Prosthesis stability

 

Bone stock

 

Suitability of femoral implant for IMN

 

Non-Operative Management

 

Indication

 

For minimally displaced fractures

 

Results

 

High rates of nonunion / malunion / stiffness

- Better outcomes with operation unless significant co-morbidities

 

Operative Management

 

Options

 

1.  Lateral locking plate

2.  Retrograde IM nail

3.  Anterograde IM Nail

4.  Revision TKR

 

1.  Lateral locking plate

 

TKR Periprosthetic Fracture Minimall Dislplaced CTTKR Periprosthetic Fracture Locking Plate APTKR Periprosthetic Fracture Locking Plate Lateral

 

Technique

 

Minimally invasive technique

- may need unicortical screws distally

 

Results

 

Kolb et al J Trauma 2010

- 19 patients treated with LISS plate

- 2 delayed union

- otherwise good union rate with minimal complications and good ROM

 

Streubel JBJS Br 2010

- compared proximal fractures to distal (beyond the femoral prosthesis)

- showed similar healing rates in each group treated with locking plates

 

Complications

 

Non union

 

Periprosthetic Locking Plate NonunionPeriprosthetic TKR Locking Plate Nonunion 2Periprosthetic TKR Locking Plate Nonunion 30001Periprosthetic TKR Locking Plate Nonunion 30002

 

Periprosthetic TKR Locking Plate Nonunion 5Periprosthetic TKR Locking Plate Nonunion 6

 

2.  Retrograde IM Nail

 

TKR Periprosthetic FractureTKR Periprosthetic Fracture 2TKR Periprosthetic Fracture Retrograde Nail 1TKR Periprosthetic Fracture Retrograde Nail 2

 

Issue

 

May be biomechanically superior

Have to open TKR to perform operation

- risk deep infection

 

Indications

 

Technically feasible

- CR knees contra-indicated

- must have sufficient sized hole in PS femoral component

- consult company as to suitablity

- small diameter nail

 

Technique

 

Minimum intercondylar distance of 12 mm

- AGC 18MM

- PFC = 20MM

- Genesis = 20MM

 

Usually remove polyethylene component

- replace after nail

- usually need new poly

 

3.  Anterograde nail

 

Indications

- sufficient bone above implant for distal locking

 

Issues

- stress riser between femoral implant and nail

- must ensure correct alignment

 

TKR Femoral FractureTKR Femoral Nail APTKR Femoral Nail Lateral

 

4.  Revision TKR

 

Indications

- very distal fracture

- insufficient bone stock

- loose prosthesis

 

Components

- stemmed, constrained implant

- tumour prosthesis

 

Case 1

 

Periprosthetic TKR Tibial Fracture 1Periprosthetic TKR Tibial Fracture 2Periprosthetic TKR Tibial Fracture 3Periprosthetic TKR Tibial Fracture 4

 

TKR Periprosthetic Fracture APTKR Periprosthetic Fracture LateralTKR Periprosthetic Fracture Revision APTKR Periprosthetic Fracture Revision Lateral

 

 

Infection

Management

Incidence

 

Knee > Hip

- superficial position

- limited cover of well vascularised muscle 

- watershed area of skin blood supply anterior to the skin incision 

- much increased in fully constrained prosthesis 

 

Ideal < 1%

 

Risk Factors

 

Increased with

- revision

- prior infection

- RA / Psoriatic arthropathy

- DM

- Obesity

 

Aetiology

 

70% gram positive cocci

- 2/3 Staph epidermidis

- 1/3 Staph aureus

 

15% Gram negative

 

Symptoms

 

Pain

Wound problems

Stiffness

 

Diagnosis

 

Xray

- progressive early lysis

 

Infected TKR Tibial Lysis

 

ESR > 10 / CRP > 30

 

Bone scan

- typically hot blood pool / early and delayed bone phase

- hot on leukocyte scan

 

Infected TKR Bone Scan

 

Aspiration

- off Antibiotics

 

Classification 

 

Gustilo 1993

 

1. Early Post-operative

- < 1/12

- febrile patient

- red swollen discharging wound

 

2. Late Post-operative

- indolent (low virulent)

- > 1/12

- well patient with healed wound

- worsening of pain / stiffness

- never pain-free interval

 

3. Acute Haematogenous

- antecedent bacteraemia

- can occur several years after surgery

- well patient with previously well functioning knee

- sudden deterioration / swelling / pain

- often have UTI etc

 

4. Positive Intra-operative Culture

- presumptive diagnosis aspetic loosening

- intra-operative M/C/S comes back positive (2 out of 5)

 

Management Options

 

Stage infection

 

Host

A Fit

B Medically compromised

C Unfit for anaesthetic

 

Microbe

- type

- sensitivities

 

Implant

- stable

- loose

 

Options

1.  Washout / debridement

2.  Two stage revision

3.  One stage revision

4.  Antibiotic suppression

5.  Arthrodesis

6.  Amputation

 

1. Debridement

 

Indications

- early post operative infection < 3/52

- acute haematogenous < 3/52 

- sensitive organism

- stable prosthesis

- healthy host 

 

Technique

 

Incision, drainage

- debridement / synovectomy

- copious irrigation

- poly exchange / also aids debridement

- 1° skin closure

- multiple swabs / tissue samples

 

Post operative

 

Administration of antibiotics depending on sensitivity

- duration of 6/52

 

Results

 

Gram Positive

 

Aboltins et al Clin Microbiol Infect 2007

- 20 patients with washout + rifampicin / fusidic acid

- risk of treatment failure 11%

- successful in 10 / 11 MRSA

 

Gram Negative

 

Martinez et al Antimicrob Agents Chemoth 2009

- gram negative acute infections in THR and TKR
- retention rates of 70%

- patients did better with a fluoroquinolone

 

MRSA

 

Bradbury et al J Arthroplasty 2009

- acute infection with MRSA

- failure rate of 84%

 

2. Two Stage Revision

 

Indication

- chronic infection

- Loose prosthesis

- failed early washout / debridement

 

1st Stage

 

Remove implant

- multiple swabs and tissue specimens

- prosthesis + cement removed completely

- preserve bone as much as able

- combination micro-sagittal saw, flexible osteotomes & burr

- complete synovectomy and debridement is crucial to success of operation

- washout +++

 

Insert Intermediate implants

 

A.  Block of antibiotic impregnated cement

 

Good at eradicating infection as high antibiotic load

- painful / poor ROM

- need to be kept in splint

- worsens bone loss

 

Infected TKR Cement Ball APInfected TKR Cement Ball LateralInfected TKR Cement Ball Bone Loss APInfected TKR Cement Ball Bone Loss Lateral

 

B.  Autoclave old femur / poly tibia or PMMA tibia

 

Technique

- reimplant femoral component

- gentamicin PMMA + added vancomycin to loosely cement in femur

- all poly tibia or create PMMA tibial component

- patient able to fully weight bear and ROM

 

Infected TKR Autoclave Femur Cement Tibia APInfected TKR Autoclave Femur Cement Tibia Lateral

 

C.  Femur and tibia made of antibitoic PMMA

 

Problem

- poor articulation / ROM

 

Infected TKR Cement Femur and Tibia APInfected TKR Cement Femur and Tibia

 

D.  Femoral implant from antibiotic cement mould / all poly tibia

 

Technique

- palacos cement (tobramycin) + 3G vancomycin per bag

- make femoral component from various size moulds

- cement in appropriate size all poly tibia with cement +++

- create a balanced knee

- patients are able to fully weight bear and ROM

- no rush to second stage

 

Interim

 

Appropriate IV antibiotics for 6/52

- assessment of resolution of infection

- CRP & ESR should remain normal after cessation Abx

- re-aspiration off antibiotics one month to confirm eradication of infection

 

2nd Stage

 

Intra-operative

 

Gram stain & FFD intraoperatively

- abort procedure if positive (>5 WBC per HPF)

- send off swabs +++

 

Careful removal of prosthesis

 

Insertion of stemmed revision prosthesis with augments

- constraint as required

- antibiotic cement

 

Infected TKR Second Stage

 

Post operative

 

Need to watch carefully for signs residual infection

 

Infected TKR Infected Second StageInfected TKR Infected Second Stage Revision

 

Results

 

Hart et al JBJB Br 2006

- 2 stage reimplantation using articulating cement prosthesis

- 42 / 48 successful (88%)

 

Anderson et al J Arthroplasty 2009

- autoclaved femur and inserted new poly in 25 patients

- only 1 failure of treatment (4%)

- excellent ROM with spacer 5 - 112o

 

Mittal et al JBJS Am 2007

- MRSA infection treated with two stage in 37 patients

- 24% reinfection rate

- 10% with MRSA, 14% with different organism

 

3.  One Stage Revision

 

Advantage

- less debilitating to patient

- less expensive management

 

Disadvantage

- increased risk of failure

 

Indication

- healthy host

- known sensitive organism

 

Technique

- remove implant / cement

- debride as above

- change all operating equipment / rescrub

- new implants with antibiotic laden cement

- post operative Antibiotics

 

Results

 

Sofer et al Orthopade 2005

- successful in 14 / 15 knees

- careful patient selection / experienced surgeon

 

4.  Antibiotic Suppression

 

Indication

 

1.  Prosthesis removal not feasible 

- patient medically unwell

 

2. Organism

- susceptibility to oral antibiotic

- minimal toxicity from antibiotic

 

3.  Prosthesis not loose

 

Results

 

Long term success very unlikely

 

Prevention

Preoperative

 

Identify high risk groups

- immunocompromised

- diabetes

- RA

- malnutrition

 

Urine screen

- check for and treat UTi

 

Groin, nose, axilla swabs

- for MRSA

- if positive, treat

- need 3 consecutive free swabs

 

3 x chlorhexidine preoperative showers in 8 hours

 

Admit day of surgery

- check skin for lesions

- cancel if concern

 

Intraoperative

 

Operating room environment

- laminar flow (300 air exchanges per hour)

- minimise staff traffic

    

Surgeon factors

- space-suit

- double glove / closed glove techniques

- Goretex gown

 

Wound environment

- preoperative clipping just prior to skin prep

- clipping better than shaving

- alcoholic chlorhexidine

- Waterproof drapes

 

Antibiotics

- intraoperative dose of antibiotics (Keflin 1g) is most important

- 30 min prior to skin incision

- 5-10 min prior to inflation of tourniquet

- vancomycin / clindamycin if allergic (takes 2 hours infusion)

- repeat if surgery > 2 hour

 

Surgery

- gentle tissue handling

- minimise surgical time

- use of antibiotic loaded cement / Tobramycin

 

Postoperative

 

2-3 doses of antibiotics (Keflin 1g qid)

Skin dressings left intact 4 days

If IDC needed then give prophylactic AB

 

 

 

 

Instability

Types of Instability

 

1.  AP Instability

2.  Varus Valgus Instability

3.  Global Instability

4. Frank Dislocation

 

TKR Dislocation APTKR Dislocation Lateral

 

AP instability

 

A.  Loose in flexion

 

Issue

- can get knee dislocation / post jump

 

Cause

- excessive posterior femoral resection

- PCL failure

 

A.  Excessive posterior femoral resection

 

Revise femur

- posterior femoral augments + stem

 

B.  Failure of PCL in CR knee

 

Revision femur and poly

- insert PS femur and poly

- need to have CCK revision equipment available

 

B.  Loose in extension

 

Excessive distal femoral resection

- revise femoral component

- distal femoral augments + stem

 

B.  Loose in flexion and extension

 

Insufficient poly thickness / wear

- insert larger poly

 

Varus-Valgus instability

 

Causes

 

A. Iatrogenic collateral ligament injury

 

Options

- advance / imbricate / augment / reconstruct collateral

- full revision to VVC / CCK constrained implant

 

B.  Failure to balance knee 

 

Cause

- under release deformity in the concavity

 

Management

- increase poly thickness, further releases in concavity

 

TKR Varus Coronal Instability TKR Varus Instability Increase Poly Thickness

 

C.  Insufficient poly / loosening over time

 

Diagnose

- equal varus and valgus instability

 

Management

- increase poly thickness

 

TKR Instability Varus and Valgus 1TKR Instability Varus and Valgus 2

 

TKR Instability Increase Poly Thickness

 

3.  Global instability

 

Unstable in  sagittal and coronal planes

 

1.  Insufficient poly thickness / poly wear

 

Options

- increase poly thickness

 

TKR Poly WearTKR Poly Wear Lateral

 

2.  Loosening / collateral ligament damage

 

Options

- revise to highly constrained prosthesis

 

TKR Global Instability APTKR Global Instability Lateral

Painful TKR

Differential Diagnosis of the Painful TKA 

 

Surgical Diagnosis  

 

1.  Prosthetic loosening and failure 

2.  Infection 

3.  Patellofemoral tracking problems  

4.  Instability 

5.  Recurrent intra-articular soft-tissue impingement / Component overhang  

 

Nonsurgical Diagnoses  

 

1.  Referred pain - Hip / Back  

2.  Reflex sympathetic dystrophy  

3.  Bursitis-tendonitis  - Pes anserine / patella / popliteal bursitis  

4.  Persistent crystalline deposition - Gout / pseuodogout 

5.  Neurovascular problems  - Neuropathy / Radiculopathy / Vascular claudication / Thrombophlebitis / DVT

6.  Expectation / Result mismatch  - Multiply operated knee / Secondary gain issues / Unrealistic expectations  

7.  Psychiatric disorders and depression  

 

Infection v Loosening

 

History

 

Postoperative course

- infection / course of antibiotics / persistent drainage post operatively

 

Nature of Pain

 

°Pain-free interval  

- indolent infection

- pathology elsewhere (pain same as pre-op)

 

Pain-free interval 

- loosening / infection / implant failure

 

Mechanical pain 

- loosening

 

Rest pain / night pain 

- infection

 

Start up pain

- loosening

- as implant settles then pain subsides

 

Examination

 

Knee painful

 

Signs infection

 

Effusion

- able to aspirate

 

Careful examination of spine / hip / vascular status

 

Xray

 

Problems

- may be normal in face of pathology

- can't DDx infection vs loosening on XR

- serial comparison very important

 

Bone Scan

 

Problems 

- very sensitive, poor specificity

- can have increased vascularity for several months

- 1 year post cemented TKR

- 18 months post uncemented TKR

 

Bone Scan TKR 12 months Diffuse Uptake

 

Advantage

- pathology unlikely if negative

 

Infection

- diffuse uptake all 3 phases (blood flow, early and delayed bone phase)

 

Bone Scan Infected TKR

 

Loosening

- focal uptake unless whole prosthesis loose

- nil increase on blood flow or blood pool

 

Bone Scan Loose TKR Normal Blood Pool PhaseBone Scan Loose TKR Increased Bone Phase

 

Bone Scan Loose TKR

 

Also diagnose

- stress Fractures

- RSD

 

Technetium Labelled White Cell Scan 

 

Uncertain role 

- expensive, difficult to perform

- have to harvest WC, label with technicium

- alone not superior, use in conjunction with bone scan

- increase sensitivity if increase on bone phase in WC and bone scan

 

White Cell Scan Infected TKR

 

Van Acker et al Eur J Nuc Med 2001

- WCC 100% sensitive but 53% specific in infected TKR


Bloods

 

WCC

 

Little value

- increased in 15%

- raised only if very septic

 

ESR 

 

> 30 mm 

- 80% sensitivity & specific 

 

Problem

- raised post operatively for up to 12 months

- remote pathology can elevate

- permanently raised in RA

- can be raised in aseptic loosening

 

CRP 

 

> 10 mg/l

- 90% sensitive & specific

- negative predictive value 99%

 

Advantage

- more predictable response post OT

- peak at day 2 (~400), normal after 3 weeks

- rarely increased with loosening

 

Aspiration

 

Technique

- no antibiotics > 4 weeks

- no LA (bacteriostatic)

- if only 1 specimum positive then repeat

 

> 65% white cells very high risk for infection

> 1700 white cells per microlitre

 

Intra-Operative Frozen Section

 

PMN Cell Count per HPF / average over 10

 

> 5 per hpf

- 84% sensitive

- 96% specific

 

> 10 per hpf

- 84% sensitive

- 99% specific

 

Intraoperative gram stain & M/C/S

 

Sensitivity < 20%, but very specific

- 10% false positive

 

Surgical Opinion

 

Sensitivity 70%

Specificity 85%

 

Patella

Problems

 

Instability / Maltracking

Fracture

Loosening or failure of component

Patella Clunk Syndrome

Extensor Mechanism Rupture

 

Incidence

 

PFJ complications 5%

 

PFJ Instability / Maltracking

 

Effect

 

Catastrophic wear

Component loosening

Pain

Fracture

 

Aetiology

 

1.  Component Malposition / Malalignment

 

A.  Internal rotation of the femoral or tibial component

- increases the Q angle

 

TKR Patella Tilt

 

B.  Medialisation of femoral component

 

C.  Axial Malalignment

- valgus > 10o

 

D.  Lateralisation of patella button

 

E.  Overstuffing of the patella femoral joint

- tightens the lateral retinaculum

 

2.  Poor patellofemoral Component design

 

A.  Poorly designed trochlea / patella

 

TKR Poorly Designed PFJ

 

B.  Hinged or constrained knee

- normally get IR with early flexion 

- this medialises tibial tuberosity

- constrained TKR don't do this and have a lateral vector

 

3. Soft tissue balancing

 

Tightness of lateral retinaculum in long standing valgus

- at end of OT should track centrally without any external pressure 

- no tilt

- otherwise lateral release +/- patella resurfacing

 

TKR Patella Lateral Tilt

 

Investigation

 

Examination

- Assess tracking


Xray

- skyline views

- lateral tilt / subluxation

 

TKR Good Patella TrackingTKR Patella Maltracking

 

CT

- rotational profile of the components

 

Management

 

Non-Operative

- VMO exercises

- often unsuccessful

 

Acute trauma

- patella has been tracking centrally since OT

- not since acute trauma

- immediate capsular repair is indicated

 

Surgical options

 

1.  Lateral release + Patella resurfacing

 

2.  Tibial tuberosity transfer +/- MPFL reconstruction

 

TKR Patella Maltracking TTT MPFL APTKR Patella Maltracking TTT MPFL Lateral

 

Barber et al Arthroscopy 2008

- 91% successul in eliminating instability in 35 knees

- used Elmslie Trillat

 

3.  Revision

 

Options

- medialise patella component

- revise malrotated components

 

Patella Fracture

 

TKR Patella Fracture

 

Incidence

 

Uncommon

- 0.1% Primary

- 0.6% Revision

 

Causes

 

1.  AVN

 

Disruption of patella blood supply

- patella turndown

- medial approach and lateral release

 

Patella AVN SkylinePatella AVN Lateral

 

2.  Excessive / asymmetric patella resection

- at least 15 mm native patella must remain

 

3.  Large central hole

- increases strain more than small peripheral holes

 

4.  Anterior patella perforation

- more common with inlay

 

5.  Increased PF strain

- oversized or anterior femoral component

- oversized patella component

- patella baja

 

Management

 

Non-Operative

 

Indications

- extensor mechanism intact

- patella component stable

 

TKR Patella Fracture Undisplaced

 

Treatment

- immobilse for 6 weeks then progressive ROM

 

Operative

 

Indications

- loose component or ruptured extensor mechanism

 

Treatment

A.  Patella ORIF if component stable

B.  Removal component if unstable + Patella ORIF

 

Patella Component Loosening

 

Incidence

 

Cemented patella

- < 2%

 

Uncemented higher

- 0.6% - 11.1%

 

Associations

 

Metal backed designs

Uncemented

Fracture / AVN of patella

Excessive bone removal

 

Management

 

A.  Remove and leave

 

B.  Revision

- need > 10 mm bone left

 

C.  Patellectomy

 

Patella Clunk Syndrome

 

Symptom

 

Clunk with knee extension

- as patella exits groove at 30-45° extension

 

Complain of symptoms when rising from chair or climbing stairs

 

Pathology

 

Fibrous nodule at junction of posterioraspect of patella and quadricep tendon

- with flexion enters trochlear groove and gets trapped as go back into extension

- usually due to entrapment at superior flange of femur

- inflammation and a synovial proliferation

 

Causes

 

Increased incidence in PS knees

 

Newer designs

- deeper patella groove

- more posterior femoral box

 

Investigation

 

Can visualise nodule on ultrasound

 

Management

 

Arthroscopic debridement

 

Dajani et al J Arthroplasty 2010

- good result in 15 knees

 

Rupture of Extensor Mechanism

 

Incidence

 

0.17-2.5%

 

Causes

 

Usually post operative, insidious and due to a vascular insult

 

Lateral release - devascularises tendon

Closed MUA of knee

Osteotomy of tibial tuberosity

Revision TKR

 

Prevention with surgical technique is imperative

 

Effect

 

Debilitating extensor lag

- can be about 50o

- operation improves this to about 20o

 

Can predispose to knee dislocation / post jump

 

Operative Management

 

1.  Primary repair with autograft / allograft reinforcement

- staples, wire reinforcement

- hamstring reconstruction (leave attached distally)

- achilles tendon allograft

- Lars ligament reinforcement

 

Usually left with extensor lag

 

Revision TKR Quadriceps RuptureRevision TKR Quadriceps Repair

 

2.  Chronic rupture / failed repair

 

Must deal with patella baja

- combine repair with proximalization of tibial tuberosity

 

TKA Chronic Quadriceps RuptureTKA Chronic Quads Rupture Repair

 

3.  Revise to constrained prosthesis if required

- PS component

- loss of mechanical advantage of quads

- extensor lag

- anterior translation of femur on tibia once the PCL stretches

 

 

 

Stiffness

 

Incidence

 

10%

 

Requirements

 

70 swing phase

80o climb up stairs

90o climb down stairs + sit down in chair

100o low chair

 

NHx

 

Stiffness usually subsides at 6-8/52

- generally improves out to 3/12

- slow improvement for up to next 9/12

 

Preoperative flexion is predictive of outcome

- <75° preoperative gain average 16°

- 95o preoperative lose average 6°

 

Causes

 

1.  Post-op pain 

 

Number one cause

- Causes quads and HS guarding

- making passive flexion and extension difficult to perform

- need adequate analgesia

- CPM not shown to shorten hospital stay or increase ROM

 

Analgesia

 

Continuous epidural infusion best, but prohibits anticoagulation

 

Combination of

- regular paracetamol

- femoral nerve catheter

- PCA / slow release opiates (oxycontin)

 

NSAIDS

- risk of renal impairment in elderly

- even COX 2

 

2.  Infection

 

Always consider with loss of ROM

 

3. Surgical Technique

 

FFD 

- may indicate too little bone resection off Distal Femur

 

Lack of Flexion

 

1. Anterior tibial Slope / previous HTO

2. Tight PCL if CR

3. Use of oversized femoral component

- narrow flexion gap / overstuffs PFJ

4. Posterior osteophytes / tight posterior capsule

 

Poor Ligament Balancing 

- important cause

- result in flex and ext problems

 

Component Malrotation

- internal rotation of tibia / femoral component

- check with CT

 

PFJ dysfunction 

 

Maltracking

Non resurfacing and pain

Joint line elevation - patella baja

 

4.  Poor Patient Motivation

 

5.  Arthrofibrosis

 

Management

 

A.  Exclude infection

 

B.  Aggressive physiotherapy and adequate analgesia

 

C.  MUA

 

Indications

- ROM < 90o at 6/52

- doesn't work for FFD

- FFD will usually resolve with time

 

Technique

- epidural catheter

- aspirate for infection

- manipulate

- post operative epidural and CPM

 

Risks

- supracondylar fracture

- patella tendon avulsion

- quadriceps tendon tears

- hematoma formation

- wound dehiscence

 

Technique MUA

- don't lever down on tibia

- hold femur

- bounce tibia up and down

- passive rather than active MUA

- be patient

 

Results

- variable in literature

- may be done up to 3/12

 

D.  Debridement

 

Open or Arthroscopic

- clear suprapatellar pouch / medial and lateral gutters

 

Judet quadricepsplasty

- above +

- release / removal of rectus femoris

- mobilisation of quadriceps from femur

 

E.  Revision

 

If mechanical problem with implant

- debride all scar tissue

- PS implant

- consider full revision if component malrotation

- resurface patella

Vascular Injury

Arterial injury

 

Incidence

 

0.05%

 

Types

 

1. Thrombosis

- most common scenario

- tourniquet with atherosclerosis

- indirect damage to vessel

- femoral or popliteal

 

2.  Embolisation

- atherosclerosis again

- blue toes syndrome post operatively

 

3.  Vessel transection

 

Presentation

- acute ischaemia post operatively

- traumatic aneurysm

- AV fistula

 

Management

- on table angiogram

- externally rotate leg 

- medial approach to posterior knee

- detach medial head of gastrocnemius

- direct artery repair / venous patch / venous or synthetic bypass

 

Problems

- 25-50% amputation rate

- deep infection and sepsis

- wound healing issues

 

History

 

Beware

- symptoms arterial insufficiency

- rest pain, intermittent claudication

- bypass surgery to heart or leg

- diabetic patients

 

Examination

 

Trophic skin changes

 

Feel for popliteal aneurysm

 

Feel for pedal pulses

 

Management absent pedal pulses

 

ABI > 0.5

- do without tourniquet

- vascular consult

- may require immediate postoperative surgery

 

ABI < 0.5

- need bypass surgery first

- certainly need pre-op angiogram

 

 

Wound Problems

TKR Wound ComplicationIncidence

 

10 -15%

 

Include

- marginal necrosis

- wound slough

- sinus tract formation

- dehiscence

- haematoma

- oozing knee wound

 

Blood supply

 

Anterior knee has no muscles to supply vessels directly 

- dermal plexus

- any subcutaneous dissection disrupts this & potentiates necrosis

- any skin flaps raised must be below subcutaneous fascia

 

Blood supply comes across medially

 

Prevention

 

1.  Avoid closely parallel scars

- 7 cm bridge is minimum

- use most lateral of 2 incisions

 

2.  Gentle tissue handling

 

3.  Avoidance of undermining & thin skin layers

 

4.  Careful closure of deep layer

- watertight, prevents oozing

 

TKR Watertight closure

 

5.  Closure with knee in flexion

 

6.  Avoid CPM

- >40° on first 3 days post-op associated with decreased oxygen tension

 

7.  Lateral Release 

- decreased skin O2 tension

- attempt to preserve SLGA

 

Concerns preoperatively

 

1.  Consult plastic surgeon

2.  Sham incision

3.  Tissue expanders

4.  Pre-op flap

- pedicled medial gastrocneumius flap + SSG

 

Patient Related Factors

 

1.  Steroids 

- decreased fibroblast proliferation necessary for wound healing

2.  RA

3.  DM

4.  Obesity 

- exposure, fat has poor and tenuous blood supply

5.  Malnutrition 

- Alb<3.5gm/L

- lymphcytes <1500 cells/L

6.  Smoking

7.  Chemo 

- MTX slight inc in wound healing problems? others none

8.  Hypovolaemia

 

Continuous Haemo-Serous drainage

 

Prolonged drainage

- 17-50% eventually become culture proven infection

 

Early management

- immobilise in splint

- local wound care

- cease anticoagulation / LMWH / Aspirin / NSAIDS

- trial vac dressing (drains haematoma / keeps sterile)

 

Drainage

- timing debatable

- rationale is that the wound in this situation is not a closed system 

- that bacteria are entering the wound while it is still draining 

- maybe better to reopen wound and debride it 

- commonly find subcutaneous or deep haematoma as cause

 

Non-Draining Haematoma

- no evidence to support drainage

- drain if causing excessive soft tissue tension or restriction of motion

 

Superficial Soft Tissue Necrosis

 

Management

- aggressive surgical debridement & closure

- < 3cm in diameter should heal

- > 3cm needs formal debridement and skin closure with SSG, flap etc

 

Full Thickness Soft Tissue Necrosis

 

Metal on view

- necessitates immediate, extensive debridement 

- medial gastrocnemius flap

 

 

Extra-articular Deformity

Causes of Deformity

 

Metabolic Bone Disease

Paget's

Fracture Malunion

Previous Osteotomy

 

Options

 

1.  Intra-articular correction

2.  Simultaneous osteotomy and TKR

3.  Staged correction and TKR

 

1.  Intra-articular correction 

 

Indications

 

Femur

- draw line of mechanical axis of femur

- line perpendicular to this / proposed distal cut

- this line must pass below insertion of collaterals

- sagittal and coronal planes

 

Max 20˚ coronal plane

Max 25˚ sagittal plane

 

Previous Unicondylar Fracture 1Previous Unicondylar Fracture 2Previous Unicondylar Fracture 3

 

Tibia 

- line drawn medullary canal of distal segment

- must pass between condyles

- maximum 30˚ varus

 

TKR Preop Tibial Deformity

 

2.  Osteotomy and TKR

 

Advantage

- bone preserving

- less bone resection to achieve correction

- augments not required

 

Disadvantage

- bigger procedure

- risk of nonunion

- must use stems to bypass

 

3.  Stage osteotomy then TKR

 

A.  Femoral Osteotomy

 

TKR Stage Osteotomy Preop 1TKR Staged Osteotomy Preop 2TKR Staged Osteotomy Post op correction

 

B.  HTO

 

Indications

- severe varus deformity

- would need > 1 cm of medial augments

 

Technique

- medial opening wedge osteotomy

- preserves bone

Navigation

Aim

 

Attempt to reduce outliers in all 3 planes of the knee

- improve alignment

- theoretically improve survival and outcomes

 

TKR Valgus Femoral Implant Non Navigated

 

Types

 

Image based

 

Pre-op CT

- uncommon

- resource heavy

 

Image less

 

Anatomic mapping and kinematic analysis of the limb

- intra-operatively 

- builds up a working model of the patient's knee

 

Indications

 

Unable to use femoral / tibial IM or EM Jigs

- fracture / metal work / deformity

 

TKR Femoral FractureTKR Previous Femoral FractureTKR Tibial Deformity

 

Bilateral TKR

- reduce post op confusion in patient

- from bilateraly IM rod

 

TKR Bilateral Varus

 

Young patient < 65

- attempt to achieve perfect alignment / balancing

- want TKR to survive long term

 

Equipment

 

2 infra-red trackers

- tibia and femur

- bi-cortical fixation

- must not move intra-operatively

- angled / positioned to be in view of camera

- must be out of way of surgery

 

Camera / optical localiser

- connected to computer and monitor

 

Pointer with infrared

 

Standard cutting blocks

- modified to allow trackers to be attached

 

Registration

 

1.  Femoral head

- rotate hip whilst minimising pelvic rotation

- kinematic registration

 

2.  Knee

- distal femoral surfaces, epicondylar axis, Whiteside's line

- medial and lateral tibial plateaus, centre of knee, posterior tibial slope

 

3.  Ankle

- medial and lateral malleolus

- ankle centre

 

Technique

 

1. Distal Femoral Cut

- leave femoral tracker in place

- cutting blocks attached

- tibial tracker on cutting block

- place at 90o to MA

- set desired resection (depth of femoral implant +/- more if FFD)

- pin block in place and cut

 

2.  Femoral AP cut

- new programs will suggest size

- determines risk of notching

- set rotation from epicondylar axis

- creat drill holes

- place cutting block and cut distal femur AP / chamfers

 

3.  Proximal tibial cut

- reattach tibial tracker

- femoral tracker on cutting block

- cut at 90o to MA

- set posterior slope

- set rotation in line with centre ankle rotation

 

4.  Newer soft ware will assess flexion extension gap

 

Problems

 

1.  Dependent on registration

- rubbish in = rubbish out

- keep pointer on bone when registering

- accurate landmarks

- movement of pelvis with femoral head rotation

- inherent soft ware inaccuracies

 

2.  May not be as accurate in rotation and sagittal planes as coronal planes

 

3.  Reasons for inaccuracy

- registration

- inaccurate saw cuts (lack of rigid fixation of blocks, width of saw blade)

- uneven cement mantles

 

Results

 

1.  Reduces outliers

 

Will place 90% of TKR's within mechanical axis +/- 3o in coronal plane

- reduces outliers

- will take a long time to see if this improves implant survival

- require large numbers of patients in randomised trials followed over 15-20 years to see a significant result

 

Lutzner et al JBJS Br 2008

- RCT image less computer navigation

- reduced number of outliers in convential group

- CT analysis showed tibial rotation inaccurate

 

Spencer et al JBJS Br 2007

- RCT of navigated v conventional

- no difference in functional outcome at 2 years

 

2.  Reduces postoperative confusion

 

Likely due to lack of IM rod instrumentation

 

Kalairajah et al JBJS Br 2006

- doppler examination of patients RCT computer v conventional alignment

- significant reduction in emboli in computer navigation

 

3.  Takes longer 

 

Up to 10-15 minutes even with extensive experience

- takes time to insert trackers and perform registration

 

Bauwens et al JBJS Am 2007

- meta-analysis

- navigation takes 23% longer

 

4.  Reduces blood loss

 

Kalairajah et al JBJS Br 2005

- RCT

- significant reduction in blood loss in computer navigation group

 

 

 

 

 

Surgical Technique Varus Knee

Goal TKR Varus OA

 

Pain relief combined with a balanced range of motion, strength & stability

 

Indications

 

Painful arthritic knee

- OA

- RA

 

Functional limitation

 

Ideal Patient

- > 65

- thin

- low functional demands

- no major medical illnesses

- not a candidate for HTO

- failed non operative management

 

Absolute Contraindications

 

Active sepsis

Inadequate soft tissue cover

PVD

°Extensor mechanism

Charcot 

 

Relative Contra-indications

 

Previous osteomyelitis

 

Young patient

 

10% 7 year revision rate < 55 in AJR

 

Poor medical condition

 

Obesity

 

Winiarsky JBJS 98

- infection 10% vs 2%

- wound complications 20%

 

Samson et al ANZ J Surg 2010

- systemic review of TKR in obese (BMI > 30)

- significantly increased risk of wound complications and deep infections

- no weight loss post TKR

 

Bilateral TKR

 

Fabi et al J Arthroplasty 2010

- increased transfusion rate

- 2.1 x increased complication rate in bilateral group

- increased complication rate in patients > 70, obese and pre-existing respiratory condition

 

Patient Examination

 

1.  Previous scars

 

2.  Sagittal plane deformity

 

A. FFD

- increase distal femoral resection by 2 mm

 

B. Flexion range

- limited flexion range may make exposure difficult

- consider extensile exposure options

- will also decrease post operative flexion range

 

C.  Recurvatum

- rare

- fill the extension gap

- will then often have limitation of flexion

- lengthen quadriceps

 

3.  Coronal plane deformity

 

Varus / valgus deformity

- ? passively correctable to neutral

 

4.  Stability

 

MCL pseudolaxity

- due to loss of medial joint space

- varus knee

 

LCL pseuolaxity

- due to lateral joint space loss

- valgus knee

 

5.  Assess PFJ

 

6.  Extensor mechanism

 

Ensure intact / no patellectomy

 

7.  Hip

 

Stiff hip (OA, RA)

- may need to address hip first

- need good flexion for TKR

 

Fused hip

- need to do TKR over end of bed

- in order to hyperflex knee to access tibia

 

8.  Foot deformity

 

Valgus foot puts valgus strain on TKR

- correct foot deformity

- or final tibio-femoral angle 2o varus rather than 7o valgus

 

9.  Pulses

 

A.  Non palpable, present on doppler

- proceed, no tourniquet

 

B.  Diabetic, non palpable or non detectable on doppler

- vascular consult

 

Xray

 

Full length standing AP X-rays

- calculate valgus cut angle

- difference between MAF and AAF

- allows assessment of any femoral or tibial deformity

 

AP and lateral x-rays

- template femoral and tibial implant sizes

 

Lateral xray

- look for patella baja (may make exposure difficult)

 

TKR Preop Patella BajaPatella Baja

 

Evaluate deformity

- need for constraint

- need for augments

- need for stems

 

TKR Severe Varus Requiring Medial AugmentTKR Excessive Medial Osteophyte

 

Pre-operative workup

 

Bloods / CXR / ECG if over 50

- medical and anaesthetic review

- swabs of groin, nose, axilla to exclude MRSA colonisation

- M/C/S of urine

- chlorhexidine showers on morning of OT

 

Equipment

 

Stems, augments and range of sizes

- correct side

- all cutting jigs available

 

Surgical Approach

 

Set up

 

Supine on table

- laminar flow

- space suits

- minimal traffic

- IV Abx, shave in OT

 

High tourniquet (if palpable pulses)

- padding underneath to distribute pressure

- wide cuff better (1.2x leg diameter)

- no prep under tourniquet

- exsanguinate first

- no evidence increases risk of DVT

 

Foot on bolster

- lateral support

- need to be able to hyperflex knee

 

Alcoholic chlorhexidine

 

Problematic previous incisions

 

1.  Longitudinal

- use if possible

- leave wide bridge if impossible (>7cm)

- if choice, always use most lateral incision

- blood supply to skin flap comes from medial

 

2.  Transverse

- intersect at 90°

 

3.  If concerned, sham incision 2/52 prior

 

Approach

 

Midline anterior longitudinal skin incision

 

Above patella to tibial tuberosity

- don't go below TT

- avoid injury to infrapatellar branch of saphenous

 

Full thickness skin and subcutaneous flap

- above superficial retinaculum

- expose VMO, medial patella and patella tendon

 

Options

 

1.  Medial parapatellar approach

 

Along medial border of patella tendon, patella 

- leave fascial flap along VMO for repair

- leave flap along side patella

- don't go into muscle

 

2.  Mid-vastus

 

Flex knee to place VMO under tension

- divide in midsubstance

 

Nestor et al J Arthroplasty 2010

- RCT of midvastus v medial parapatella

- mild increase strength at 3 weeks

- no other benefit

 

3.  Subvastus

 

Preserves extensor mechanism

- elevate VMO off medial intermuscular septum

 

Jung et al Int Orthopedics 2009

- subvastus v medial parapatella

- earlier SLR and better flexion at 10 days with subvastus

 

4.  Lateral approach 

- valgus knee > 20°

 

Evert patella

 

Flip laterally

- homan / ring handled spike retractor inside to hold

 

Can just create a lateral pocket in fat and slide patella

 

Extensile Approaches if cannot Evert Patella

 

1.  Quadriceps "Snip"

 

Extend medial parapatellar arthrotomy laterally 

- distally to proximal across rectus

- obliquely in superolateral direction

 

No real post operative changes in rehab

- little loss of extensor power 

 

2.   Patella turndown (Insall)

 

Inverted V

- second incision 45o to medial incision

- dissection distally via tendon of VL & lateral retinaculum

- stop short of and preserve SLGA

- can convert to VY plasty

 

Repair with nonabsorbable suture 

 

Problems

- patella necrosis

- weakens extensor mechanism

 

Post op

- protect from flexion 2/52

 

3.  Tibial Tuberosity Osteotomy

 

Incision extended distally to expose proximal 10 cm tibia

- raise medial periosteal - osseous flap

- saw / osteotomes

- about 8 x 2 cm

- 1 cm thick

- leave attached laterally and hinge open

- reattached with wires or screws

 

TKR Tibial Tuberosity Transfer APTKR Tibial Tuberosity Transfer Lateral

 

Post op

- limit active extension

- limit passive flexion

 

In revision

- use wires that pass about stem

- 3 x wires

- 3 x drill holes in lateral aspect of bone hinge

- pass about stem

- 3 x drill holes in medial tibia

 

Soft Tissue Release

 

Removal ACL +/- PCL

Osteophytes debrided

Removal of meniscus

Removal of fat pad if further exposure required

 

Medial release

- knee in extension

- medial tibial periosteum is elevated 

- a narrow Hohmann retractor positioned subperiosteally around the medial border of the medial condyle

- residual periosteum is dissected posteromedially to the level of the insertion of the semimembranosus

- with increasing levels of varus will continue posterior and release SM

 

Bone Resection

 

Options

 

Advantage femur first

- makes the tibia easier to access

 

Advantage tibia first

- can mark on femur appropriate rotation of AP resection in flexion 

- can use tensioner / flexion extension gap resection method

 

Distal Femoral Resection

 

Theory

- the tibia is cut at 0o

- want residual tibiofemoral axis to be 3-7o

- therefore, instead of cutting femur at 7-9o valgus, cut at 5-7o

- matched malalignment

 

Lateral plane

- at right angles to anatomic axis

 

Alignment

 

A.  Intra-medullary best

B.  Extramedullary less accurate 

C.  Significant deformity of femur / THR

- may need to use EM / short IM / computer navigation

 

TKR and THR

 

Entry point

 

Clear osteophytes from intercondylar notch

 

Point

- 7 - 10 mm anterior to ACL

- slightly medial

- palpate femoral shaft

- pass IM drill reamer

- enlarge the hole to vent fatty contents

 

A. If entry too posterior 

- will flex the femoral component and limit extension

 

B.  If entry too lateral

- distal cut will be made in excessive valgus

 

TKR Valgus Femoral Implant

 

Place IM rod & distal femoral cutting Jig

 

Distal resection

 

Valgus angle

- pre-op valgus cut angle

- 0o to mechanical axis

- 5 - 7o from anatomical axis

- usually 5o tall and thin, 7o short and fat

 

Resection depth

- cut 8mm for resurfacing (thickness of femoral component) from most distal surface

- increase if FFD (10 mm)

- sets joint line

- the 8 - 10 mm will always be from the lateral side

- the thickness of the medial resection is > thickness of lateral resection

 

TKR Distal Femoral Valgus Cut

 

Joint line

 

Position

- 3 cm below medial femoral epicondyle

- 15 mm above fibular head

- at meniscofemoral ligament / mensical remnant

 

A.  Elevation of joint line

- excess distal femoral resection for FFD

 

Effect

- may need to use PS instead of CR to maintain flexion balance

- generates patella baja

- extension gap larger than femoral gap

 

B.  Lowering of joint line

- excessive tibial resection

 

AP Resection

 

A.  Anterior referencing

- measure from anterior down

- if between sizes down size

 

Advantage

- avoid notching

- avoid overstuffing PFJ

 

Disadvantage

- loose flexion gap from downsizing

 

B.  Posterior referencing

- posterior condyles up

- if between sizes upsize to avoid notching

 

Advantage

- stable flexion gaps

 

Disadvantage

- overstuff PFJ

- be aware of insufficient posterior condyles / IR

 

Size Femur with sizing guide

 

Clear synovium anteriorly

- seat feet of sizer on posterior condyles

- use stylus anteriorly

 

Note

- anterior or posterior referencing is built into jig

- both have feet to place on posterior femoral condyles

 

Between sizes

- up size

- move jig anteriorly appropriate amount

- avoids notching

- resects more posterior femoral condyles

 

Set Rotation of AP cutting block

 

Externally rotate femur

- normal patella tracking

- equal flexion extension gap

- should cut more off anterior aspect of lateral condyle than medial condyle

 

1.  Posterior Condylar Axis

- need to ensure no posterior deficiency or posterior condylar asymmetry 

- cutting block must be set 3o ER to this line

 

2.  Epicondylar Axis

- lateral epicondylar prominence and medial sulcus of the medial epicondyle

- set cutting block parallel to the epicondylar axis

 

3.  Whiteside's line

- Whiteside's line midline of trochlea

- most reliable

- should be 90o to epicondylar axis

 

Once size and rotation is set, drill holes for the cutting guide

- recheck the drill holes are on the appropriate axis

- ensure appropriate rotation

 

Anteriorly

- resect more lateral condyle than medial

 

Posteriorly

- resect more medial condyle than lateral

 

AP and chamfer cuts

 

Apply block

- ensure no anterior notching (femoral cortex proximal to trochlea)

- use angel wings to do so

- make anterior resection

- before posterior resection must protect LCL and MCL

- insert Homan retractors under collateral ligaments

 

PCL block resection

 

Separate Cutting Block

 

Medial / Lateral positioning important

- cover femur with component

- minimise overhang

- prefer to tend laterally for patella tracking

 

Resect box for femoral cam

 

Tibial Bone Cut

 

Alignment

 

Intramedullary guide

- less accurate with any tibial deformity

 

Extra-medullary guide

- most accurate

 

Extramedullary Alignment

 

Maximally flex knee

- retractors each side

- forked tongue, blunt homans retractor behind tibia to sublux forward

 

Centre jig at knee

- pin centre of interspinous eminence

- junction middle / medial two thirds tibial tubercle

- impact first pin on jig

 

Set rotation at knee

- rotate to tibial crest

- impact second proximal pin on jig

 

Tibial component rotation 

A.  Internal rotation of component

- will give valgus due to posterior slope

- results in tibial ER & increased Q angle

B.  Cut tibia when ER

- posterior slope creates varus

C.  Cut tibia when IR

- posterior slope creates valgus

 

Centre jig over talus

- line up with second MT

- halfway between medial malleolus and anterior fibula

- between EHL / EDL

- always tend to go towards medial malleolus to avoid varus which is most common mistake

- should align over tibial crest

 

Posterior slope

 

Normal posterior slope is 10o

- decreased by menisci to 3o

 

If tibia is cut at 90o, increased risk of tibial subsidence

- if flat poly design, cut at 10o

- if oblique poly design, can cut at less

 

Bone anteriorly is poor

- therefore usually wish to cut with a posterior slope to preserve anterior bone

- degree of posterior slope also built into poly

 

Check posterior slope

- usually built into cutting block

- ensure matches current slope

- use angle wings

 

Excessive posterior slope

- resects PCL origin

- loose in flex

- excessive metaphyseal resection

 

Anterior slope

- limited flexion

- decreased flexion gap

 

Set resection depth

 

Options

- resect 2 mm from worn side (medial)

- resect 10 mm from normal side (lateral)

- use stylus

 

Best to cut from lateral side

- have set joint line distally on femur from lateral side

- best to continue to do so from lateral side

- in a varus knee the medial joint line is worn

- lateral joint line is usually preserved

- enables preservation of anatomic joint line

 

Pin block in place

 

Pin in place 2 pins

- drill first

- prevents pins being divergent 

- allows adjustment of block

 

Double check tibial cut

 

Drop rod

- double check alignment

- ensure over centre of talus

- can adjust

- insert 3rd oblique pin

 

Recheck resection level with angel wings

- take more off lateral than medial

- ensure lateral side not more than 1 cm

 

TKR Tibial Cut

 

Over-resection

1.  Lowers joint line

2.  Poorer strength cancellous bone

3.  Decreased surface area

4.  Removes PCL / requires PS

 

Severe varus deformity

 

Problem

- 10 mm from lateral side does not take medial bone

- do not cut to level of medial defect as cancellous bone of the tibia becomes weak

 

TKR Severe Varus Requiring Medial Augments

 

Solution

- stay subchondral on lateral side

- never more than 10 mm cut lateral side

- build up medial side

 

Options

 

1.  Cement

 

2.  Autologous bone graft

- may have enough in primary

- from posterior or distal femoral condyles

- supplement with 2 screws

 

3.  Augments

- 5 - 10 mm

- use stems if use augments

- offsets forces to the diaphysis (up to 30%)

 

Cut tibia

 

1.  Protect MCL / LCL with retractors

2.  Protect NV structures

- anteriorly sublux tibia

- forked tongue / broad homan protecting posteriorly

3.  Protect patella ligament

- can cut lateral side with saw

4.  Protect PCL if CR

 

Clear posterior femoral osteophytes

 

Lift up femur / insert IM rod / push tibia posteriorly

- feel with finger

- curved osteotomes

 

Soft Tissue Balancing

 

Trial

 

Place trial tibia and femur

- trial poly (minimum 8 mm)

 

Coronal plane balancing

 

Tight in extension medially

- ensure all osteophytes released

- release semimembranosus

- release posterior half MCL

- release medial posterior capsule with curved osteotomes

- release pes

 

Tight in flexion medially

- release PCL

- release anterior MCL

 

Sagittal Plane Balancing

- trial flexion and extension gaps

- 6 possible problems (see TKR / Balancing)

 

Set rotation of tibia / prepare tibia

- ensure full medio-lateral coverage

- no medial overhang to avoid impingement

- can have some slight lateral overhang

- tend to have to compromise in the AP plane 

- should usually align with medial third of tibial tuberosity

- cut keel for tibia after ensuring correct rotation

 

Patellofemoral joint

 

1.  Not resurfacing

- remove osteophytes

- denervate

 

2.  Resurfacing

 

Onlay technique

- caliper measure thickness of patella

- aim to reproduce this with button

- size patella button

- each button size has an appropriate resection

- aim to leave minimum 15mm bone

- apply cutting jig

- ensure flat medial to lateral cut

- place button jig / medialise button / drill peg holes

 

Inlay technique

- caliper measure thickness patella

- size patella

- patella will have specific depth to drill

- ensure leaves adequate patella thickness above peg holes

 

Fixation and Closure

 

Prepare

 

Wash all surfaces

- H202

- dry with sponges

- good exposure of tibia

 

All components opened / checked / ready

 

Cementing

 

Antibiotic impregnated low viscosity cement (Palacos)

- 1 - 2 mixes

 

Tibial metal tray first

- pressurise into tibia

- insert tray, ensure correct rotation

- compress, even cement mantle

- clear all cement

 

Insert poly

- definitive / trial

 

Femoral component

- place cement on exposed surfaces, compress

- small amounts cements posterior femoral condyle area of femoral component

- impact, ensure not flexed

- remove excess cement

 

Extend leg / wait for cement to set

 

Insert definitive poly if used trial originally

- can retrial

- this step is difficult if using PS poly

 

Patella tracking

 

Check 

- one thumb technique

- flex and extend knee

 

Lateral retinacular release

- internal surface

- longitudinally

- protect SGA superiorly

- distally to lateral margin patella tendon

- proximally to just above superior patella

- not into vastus lateralis

 

Closure

 

Tourniquet release

 

Hersekii et al Int Orthop 2004

- RCT of tourniquet release to obtain hemostasis v tourniquet release after dressings

- increased blood loss with early release

- no difference in post op Hb, transfusion, operation or tourniquet times

 

Drain

 

Parker et al JBJS Am 2004

- meta-analysis

- using a drain increases transfusion requirement

- no difference in wound complications or infection

- more likely to need to augment dressings without drain

 

Closure

 

Water tight to prevent haematoma drainage

- 4-5 1 vicryl figure 8 sutures

- 1 vicryl locking suture

 

Post operatively

 

IV ABx x 4

 

Anticoagulation

 

Low dose LMWH that night or next day for 4 weeks

TEDS / SCD's

Early mobilisation

 

Analgesia

1.  Intra-articular analgesia

- combinations LA / NSAIDS

2.  Epidural

3.  Femoral nerve blocks / sciatic nerve blocks

4.  PCA

5.  NSAIDS

6.  Long acting oxycontin early

- aids wean off PCA

 

Physiotherapy

 

Immediate weight bearing and ROM

- quadriceps exercises

- can use splint until SLR

- need adequate analgesia

 

CPM

 

Advantage

- improves clearance of blood from joint

- reduces need for analgesia

- increases early ROM

 

Disadvantage

- no evidence improves outcome

- interferes with wound healing

 

 

TKR Design

Bearings

Types

 

1.  Fixed bearing

 

Insall-Burstein II knee

- cannot be fully conforming

- otherwise would be very constrained to axial rotation

- would transfer large rotational stresses to the prosthesis bone interface

 

2.  Mobile bearing 

 

LCS (meniscal bearing)

- allow fully conforming articulations

- because they allow unconstrained axial rotation at the poly / tibial interface

- reduced axial stress to the prosthesis bone interface

 

PE wear in TKR

 

2 types

 

1.  Articular Wear

 

Kinematic conflict

- increasing contact area reduces contact stress

- but it reduces ROM

 

Highest

- low conformity

- round on flat designs (PCL retaining)

- increased ROM but high contact stresses in the poly

- sliding and skidding 

- delamination and particle production

 

Lowest

- highly conforming designs

- PCL retaining

- this produces less ROM

 

This is the kinematic conflict

- want to increase conformity to decrease wear

- but want increased ROM

 

2.  Under-surface Wear

- between poly and tibial baseplate

- no locking mechanism is 100% reliable 

- some movement occurs

- resulting in particle production

- one way to avoid this is to use an all poly tibia

 

Mobile bearing

 

Goal

 

1.  Maximise conformity by allowing mobility of the bearing surface

 

2.  Increase contact area & decrease long term wear

- reduce stresses at implant - implant and implant bone interface

 

3.  Recreate normal knee kinematics

 

Advantage

 

Decreased wear due to decreased contact stresses (unproven)

- may compensate for any malrotation

- do they solve the kinematic conflict by allowing highly congruent surfaces whilst maintaining good ROM? (unproven)

 

Disadvantage

 

1.  Bearing Dislocation

- soft tissue and ligamentous balancing crucial

- severe deformity is a contra-indication

 

2. Anterior soft tissue impingement with AP translation

 

Types

 

A.  IR and ER

- cone in cone constraint mechanism

- backward motion of one condyle / forward motion of the other

- i.e. LCS RP (low contact stress rotating platform, PS)

 

B.  IR and ER on medial axis

- better stimulation of anatomic motion

 

C.  IR and ER + AP 

- meniscal bearing

- relies on ligamentous structures for stability

- CR or PS

- i.e. LCS meniscal bearing CR

 

D. Guided motion IR and ER + AP

- controlled by intercondylar saddle shaped cam

- attempt to reproduce normal knee kinematics

- rollback with flexion / roll forward with extension

 

Biomechanical Studies

 

LCS Mensical Bearing

 

LCS Meniscal Bearing wear simulator

- 1% loss over 10X106 cycles 

 

Contact area 

- 200 mm x mm in fixed bearing

- >1000 mm x mm in mobile bearing 

 

Contact stresses 

- reduced from 25mPa to <5mPa

 

Results

 

ROM / Function

 

Rahman et al J Arthoplasty

- RCT of mobile v fixed bearing

- no difference in ROM or functional scores

 

Ladermann Knee 2008

- RCT of mobile v fixed bearing followed up for 7 years

- no difference in ROM or outcome

 

2 x meta-analysis show similar findings

 

Survival / Wear

 

Australian Joint Registry 2010

9 year revision rate with OA as primary diagnosis

 

Fixed bearing                         4.7%

Mobile Bearing Rotation           5.7%

Mobile Bearing Sliding             6.7%

 

 

 

 

 

Conformity Materials Fixation Gender

Conformity

 

Definition

 

Geometric measure of the closeness of the fit of the knee articulation

 

Concepts

 

The ideal TKA maximises articular conformity while minimising axial constraint

 

Highly conforming / Fully congruent

- constant sagittal femoral radius

- large contact areas

- theoretical limitation of flexion to 120o due to posterior impingement of the tibial component

- low wear rates

- poor ROM

- may be improved by mobile bearing

 

Low conforming / Partially congruent

- large contact areas in the first 20o of flexion

- contact area decreases with flexion due to a decreasing sagittal radius

- improves flexion range

- good ROM

- higher wear rates

 

Tibia all poly v metal backed

 

All poly tibia

 

TKR All Poly Tibia APTKR All Poly Tibia Lateral

 

Advantage

- cheaper (by $2000)

- good in elderly patients

- eliminates backside wear

 

Disadvantage

- lack of modularity

- difficult to insert if PS

 

Metal backed

 

Advantage

- improved load distribution

- modularity improves revision options (i.e. poly exchange)

- modularity enables increasing trialling before definitive implants

 

Disadvantage

- problems with locking mechanism

- most have some micromotion

- potential for backside wear / increased particulate debris

 

TKR Dislocated Fixed Bearing Poly

 

Fixation

 

Best technique controversial

 

Options

 

1. Cemented

2. Press-fit with porous ingrowth

3. Hybrid

 

Cemented

 

Current standard

- longest follow up

- cement "Seal" to particle migration

- easier to revise if infected

 

Uncemented

 

Initial results comparable

 

Risks

- very difficult to remove well fixed uncemented infected TKR

 

Advantage

- faster operation

 

Results

 

Baker et al JBJS Br 2007

- RCT of PFC cemented v uncemented

- 15 year follow-up

- 80% 15 year survival in cemented

- 75% 15 year survival in uncemented

 

Australian Joint Registry 2010

 

9 year survival

- cemented TKR      5.0%

- uncemented TKR  5.2%

- hybrid TKR           4.9%

 

Materials

 

Cobalt chronium femur

- can be covered with oxidised layer

- S&N oxinium

 

Cobalt chronium tibial base plate

- can be porous and HA coated

 

Gender

 

Anatomic differences

 

Female Femur

1.  Narrower medial lateral width for same AP diameter

2.  Variety of subtle PFJ anatomical and biomechanical differences

 

Evidence

1.  No evidence showing increased failure rates in men compared to women

2.  No evidence of improved outcome for women using gender specific knees

 

 

 

 

 

Constraint

Philosophy

 

Need the least amount of constraint necessary to obtain sufficient stability

 

Increasing constraint

 

Advantages

- increase stability

 

Disadvantage

- increase stress at implant host interface

 

3 Types

 

1.  Unconstrained

 

A.  Posterior cruciate retaining

B.  Posterior cruciate substituting / Posterior stabilised

 

2.  Constrained non hinged

 

3.  Constrained hinged

 

CR / PCL retaining

 

TKR Cruciate Retaining

 

Known Advantages

 

1.  PCL acts as knee stabiliser 

- prevents anterior dislocation of femur on tibia

- provided is correctly balanced

 

2.  No risk of Cam jump / Post wear

 

3.  Improved bone stock preservation on the femoral side

 

Theoretical Advantages

 

1. ? Improved knee flexion 

 

Theory

- preserves femoral rollback / increases flexion

- posterior shift in the femoral-tibial contact point in the sagittal plane as the knee flexes

- posterior shift allows the posterior femur to flex further without impinging on the posterior tibia

- allow better flexion by allowing rollback

- kinematic studies show that this rollback is imperfect

- combination of rolling and sliding

 

Victor et al JBJS Br 2005

- II study of PS v CR

- showed improved femoral rollback in PS

 

Maruyama J Arthoplasty 2004

- RCT of PS v CR

- improved ROM in PS

 

2.  ? Increased quadriceps strength, stair climbing and proprioception

 

Swanik et al JBJS Am

- RCT of CR v PS

- no detectable difference in proprioception or balance

 

3.  Fewer patella complications

 

Disadvantages

 

1.  More difficult to balance

- PCL often scarred

- tight in flexion / limited flexion / anterior lift off

- can downsize femoral component, increase posterior slope, recess PCL

 

2.  Increased wear in early designs

- without ACL, rollback is a combination of roll and slide

- for rollback to occur the tibial PE must be relatively flat

- this created high contact stresses and rapid poly wear and failure

 

New designs

- increased conformity

- congruent PE insert allowing less rollback

- reduces contact stresses on PE

- relegates PCL to a static stabiliser to prevent anterior dislocation of the femur

- increased knee flexion is then obtained by having a posterior offset centre of rotation (4-6mm) and recreation of normal posterior slope

 

Can actually get paradoxical rollback

- actually rolls forward

- increases anterior wear

 

PC substituting / PS

 

TKR Posterior Stabilised

 

Design

 

1.  Tibial PE post with a femoral cam

- femoral cam engages the post at a designed flexion point

- prevents femur translating anteriorly

- with further flexion get rollback

 

2.  Deeply dished articular surfaces

- increased conformity

 

3.  "Third condyle"

- limits excessive tibial translation

 

Known Advantages

 

1.  Eliminate risk PCL rupture

 

2.  Easier to balance / correct severe deformity

 

Theoretical Advantages

 

1. ? Reduced wear 

- increased conformity

- because rollback is mechanically controlled, can have congruent articular surfaces

- reduces contact stresses on the tibial poly

 

Disadvantage

 

1.  Risk of Cam jump

- must have good balancing

- if loose flexion gap femur can jump  over the tibial post 

- this can also occur with good balancing

- in hyperflexion, the femur will impinge on the tibial post and be levered over

- may wish to have CR if postoperative flexion is anticipate to be > 130o

 

2.  Increased loss of bone stock

- due to making cuts for box in femur

 

3.  Increased wear of tibial post in femoral cam

- theoretic risk

 

4.  Increased patella clunk (older designs)

 

Indications

 

1.  Previous patellectomy

- better outcomes with PS c.f. CR

 

TKR Patellectomy Preop APTKR Patellectomy Preop Lateral

 

2.  Inflammatory conditions

- risk late PCL rupture

 

3.  Previous PCL rupture

 

4.  Over-release of PCL during surgery

 

5.  Difficult balancing

- valgus knee

- severe varus knee

 

Results

 

ROM

 

Harato et al Knee 2008

- multicentred RCT of PS v CR Genesis II at 5 year follow up

- no difference in functional assessment, patient satisfaction or complication

- improved ROM in PS

 

Survival

 

Australian Joint Registry 2010

- significantly higher revision rate with PS

 

9 year survival rate

- minimally stabilised 4.8%

- posterior stabilised 6.0%

 

2.  Constrained Non Hinged / Varus Valgus Constrained (VVC)

 

TKR High Post CCK APTKR High Post CCK Lateral

 

Design

 

1.  Large metal reinforced post in deep femoral box

- provides greater coronal plane stability

- variable varus/valgus stability as well as rotation

- permit 2-3o of varus-valgus movement

- 2o of internal/external rotation

 

2.  Stems

- transmit the increased stresses away from the fixation interfaces to diaphysis

- otherwise increase risk of early loosening

 

TKR CCK failing as no stems APTKR CCK failing as no stems LateralTKR CCK Bone Scan Loose

 

Indications

- severe valgus deformity

- collateral ligament deficiency

- bone defects

- irreconcilable flexion-extension imbalance after PS implant

 

Disadvantage

- increased bone loss

- potentially higher rate of aseptic loosening

- fracture of the tibial stem

- recurrent instability

 

Types

 

Total Condylar III / TCIII (Depuy)

CCK / Condylar constraint knee

Legion (S&N)

 

Results

 

Lachiewicz et al J Arthroplasty 2006

- 10 year follow up of CCK in primary TKR

- severe valgus with incompetent MCL / severe FFD unable to be balanced

- only 2 / 54 revisions or 10 year survival 96%

- 86% good or excellent results

 

3.  Constrained Hinged / Rotating Hinged

 

Revision TKR Rotating Hinge APRevision TKR Rotating HInge Lateral

 

Design

 

1.  Uniplanar hinge

- prohibited rotational motion

- high rate of aseptic loosening

- historical

 

2.  Rotating Hinge 

- linked with an axle

- restricts varus-valgus and translation

- permit rotation of the tibial bearing about a yoke on the tibial platform

- again need long stems to disperse forces

 

Disadvantage

- increased bone resection

- increased risk of aseptic loosening

- unusual breakages / dislocations / failures

 

Indications

- severe collateral instability

- severe bone loss

 

Results

 

Petrou et al JBJS Br 2004

- 100 rotating hinge prosthesis followed up for average 11 years

- average patient age 70

- good or excellent results in 91%

- 15 year survival 96%

- one supracondylar fracture / one dislocation / 2 deep infections

 

Constraint Algorithm

 

1.  Severe varus > 15o, intact collaterals

 

Laskin Clin Orthop 1996

- improved pain scores and survivorship for PS over CR

- due to improved balancing and correction of deformity

 

2.  Severe Valgus

 

PS if MCL intact

- VVC if MCL severely attenuated or ruptured +/- MCL reconstruction

- if very unstable in both flexion and extension, may need rotating hinge

- difficult to know exact indications for VVC v hinge

- judgement call (age, bone stock etc)

 

3.  RA

- concern re late PCL instability and recurvatum 

 

Hanyu J Arthoplasty 1997

- recommend PS

- however, be mindful that this group also has an increased rate of late dislocation over the tibial post

- 6.5% at 8 and 10 years post op

 

4.  Patellectomy

- better functional and pain scores if use PS rather than CR

 

5.  MCL attenuated (i.e. valgus knee)

 

A.  Use PS and load the lax  side 

- mild to moderate

 

B.   PS + MCL advancement / imbrication / reconstruction 

- moderate to severely attenuated

- can make balancing difficult

 

C.  VVC / rotating hinge

 

6.  Intra-operative MCL injury

 

Either avulsed (femur) or cut mid-substance

- can use VVC but unlikely to have on hand

- use PS

- reattach / repair / augment MCL

- postoperatively hinge brace 6/52

 

Leopold JBJS Am 2001

- 16/16 patients no coronal plane instability with this treatment

 

 

 

 

Patella Resurfacing

Options

 

1. Always resurface

2. Never resurface

3. Selectively resurface

 

Decision Making

 

Controversial

- literature divided on issue

 

Historically

- poor outcomes due to poor implant design

- now improved designs

- non resurfacing also improved due to better design and improved techniques in regard to tracking and rotation

 

TKR Patella Non Resurfaced Poor DesignTKR Non Resurfaced Patella Skyline

 

Advantages of resurfacing

 

Theory

- reduced anterior knee pain

- improved stair climbing

- reduced revision rate

 

Confounder

- patients with post operative pain and non resurfaced patellas

- are able to have a revision as a means of addressing their pain

- resurfaced patients are not

 

Disadvantage of resurfacing

 

Complication rate of ~10%

 

1.  Implant failure

- early metal-backed high failure as thin poly & poor fixation poly to metal

- decreased incidence with all-poly components (1% of all revisions in AJR)

 

2.  Fixation failure 

- problem with overly aggressive bone resection & poor patellar preparation

 

3.  Patella fracture

- caused by excessive bone resection & holes in patella for fixation

 

4.  Dynamic instability

- instability 2° component malalignment & inadequate soft tissue balancing

- incidence of 4%

- mal-tracking / subluxation / dislocation

 

See TKR Complications / Patella

 

Resurfacing Indications

 

TKR Patella Resurfacing

 

Absolute

- inflammatory arthritis

- mal-tracking

- PF OA as main indication for TKR

 

Patella OA SubluxationPatella Tilt OA

 

Relative

- severe OA (Gd 3/4) / pain PFJ

- elderly

- obesity

 

Non Resurfacing Indications

 

TKR Non Resurfaced Patella

 

1.  Young

- non inflammatory arthritis

- minimal OA changes

- normal tracking

- high risk of revision in future

 

2. Revision TKR with difficulty achieving fixation

 

3. Thin patella

- need at least 15mm post resection

 

Non Resurfacing Complications

 

PFJ Pain

 

Reported incidence of 10-25%

- poor stair climbing

- deterioration over time

- need for later resurfacing

 

Increased with

- inflammatory arthropathy

- poor tracking

- obvious OA 

 

Selective Resurfacing

 

Resurface if

- Gd 4 PFJ OA

- abnormal tracking

- inflammatory arthritis

- old age

 

Patella Prosthetic Design

 

Metal Backing of Patella

- good fixation to bone

- but thin poly, getting wear and catastrophic failure

- poly can detach from metal

- out of favour

 

Anatomic patella

- no central plug

- femoral prosthesis deep conforming patellar groove & raised lateral flange

 

Central Dome 

- most adaptive with least congruity

- button

- most common

 

Polyethylene

 

Cold Flow

- stresses measured exceed yield point of PE

- would predict much higher wear rates & loosening than observed clinically

- poly may experience "Cold Flow" which would change contact stresses over time

 

Soft tissue adaptation

- more likely explanation than change in shape of poly

- pseudo-meniscus of fibrous tissue often forms around the unloaded portion of patella component 

- may transfer load to peripheral soft tissue

 

Femoral Design

 

Deeper trochlea groove

- provides patellar stability

 

Raising the lateral wall

- controls tracking

 

Increased congruency between patella and trochlea

 

Proximal extent of the anterior flange

- need adequate proximal extension

- minimises chance that the patella will ride off flange proximally in terminal extension

 

Inlay v Onlay

 

Onlay

- standard technique

- cut patella

- cement all poly patella

 

TKR Patella Onlay

 

Inlay

- resect into the patella

- cement poly into patella

 

TKR Patella Inlay

 

Surgical Technique

 

1.  Appropriate component position

- femur 3o ER, lateral placement

- tibia slight ER, lateral placement

- restore mechanical axis

 

2.  Restore thickness of patella

 

Under-resection

- overstuffs PFJ / anterior knee pain

- increases joint reaction force

- decreased flexion

 

Over-resection

- predispose to fracture

- ensure 15mm minimum

 

3.  Avoid tilting patella

 

Symmetric bone resection

 

4.  Ensure tracking well

 

Combination prosthetic positioning and soft tissue balancing

 

A.  Patella button placement

- medialise component 

 

B.  Lateral Release

- assess tracking before retinacular closure

- perform lateral release if patella shows tilt or subluxation

- from "Inside Out"

- preserve LSGA if possible

 

Patella Baja

 

TKR Preop Patella Baja

 

Problem

- limits flexion

- due to patella impingement on tibia in flexion

 

Causes

- HTO

- tibial tuberosity transfer

- tibial fracture

 

Solutions

 

1.  Lower joint line

- cut more tibia, distal femoral augments

 

2.  Resurface patella and place button superiorly

- effectively lengthens the patella tendon

 

3.  Shave anterior surface of PE

 

4.  Trim but don't resurface patella

- resect

- shave off inferior aspect of patella

 

Results Resurfacing v Nonresurfacing

 

Burnett et al JBJS Am 2009

- ten year follow up of RCT in 118 knees

- no difference in ROM / function / global or anterior knee pain

- 7 patients (12%) had revision in non resurfacing related to PFJ

- 2 patients (3%) in resurfacing group relating to PFJ

 

Stirling et al JBJS Br 2006

- RCT of 100 knees with 10 year follow up

- 2 patients in non resurfacing had revision of PFJ

- 1 patient in resurfacing had a lateral release

- unable to recommend routine resurfacing

 

Waters et al JBJS Am 2003

- RCT of 500 knees followed up for 5 years

- AKP 25% in non resurfaced group

- AKP 5% in resurfaced group

 

Pakos et al JBJS Am 2005

- meta-analysis

- resurfacing had reduced reoperation rate of 4.6%

- would have to resurface 22 patella to prevent revising 1

- resurfacing had reduction of anterior knee pain of 13%

- have to resurface 7 patella to prevent AKP in 1

 

Australian Joint Registry 2010

 

9 year survival

- non resurfaced / CR  5.2%

- non resurfaced / PS  7.8%

- resurfaced / CR        4.3%    

- resurfaced / PS        4.6%

 

 

 

 

Poly Design and Wear

Definition

 

Loss of material from solid surface due to mechanical action

 

Types of wear

 

TKR

- more complex movements compared with THR

- rolling, sliding and rotation

- delamination, pitting and fatigue failure of the poly surface

 

Types

- adhesive wear (most common in TKR)

- abrasive wear

- third body wear

- fatigue wear - delaminating

- wndersurface wear

 

Patient factors

 

Age

Weight

Activity

Inflammatory arthritis

 

UHMWPE

 

Site of wear

 

Frontside

- articular side wear

- conformity

- PS v CR

- mobile v fixed bearing

 

Backside

- undersurface wear

- between baseplate and poly

 

Manufacturing

 

1.   Compression moulding of poly

- moulding the powder into shape required

- less wear in vitro

- 0.05mm wear/yr 

 

2.  Machined poly

- from a poly sheet or bar

- may generate subsurface cracking

- predispose to sublamination

- 0.11mm /yr wear

 

Sterilisation

 

Gamma irradiation in air

- creates oxygen free radicals

- then stored in oxygen rich environment

- created a sub surface band of highly oxidised PE

- decreased mechanical strength

- increased wear

- worsened by long storage times (8-10 years)

 

Modern sterilisation

- ethylene oxidation / gamma irradiation

- oxygen free environment

 

Conformity

 

Conforming prostheses i.e. LCS & IB II approx 1/2 max stress levels of other designs

 

1.  Highly conforming surface stresses are maximal at the surface

 

2.  Increased contact area 

- increases stress distribution

 

Thickness of Poly

 

Thinner poly inserts exhibit greater wear than thicker inserts of the same design

- yield strength of poly exceeded if < 4mm poly

- if add 4mm poly reduce stresses by 27%

- definitely if < 6 mm

- no improvement > 8 mm

 

Backside wear

 

Locking mechanisms

- snap fit

- tongue in groove

 

These mechanisms may lose stability over time

- increase particulate wear

 

Lead to interest in all poly base plate

 

Femoral component

 

Decrease wear at post-cam interface

 

Increase surface smoothness and hardness

- oxinium

 

Surgical Factors

 

Mechanical alignment

- coronal

- sagittal

- rotation

 

All can contribute to abnormal loading and wear

 

 

 

 

 

Valgus TKR

 

TKR Moderate Valgus OAValgus Malalignment

 

Definition

 

A valgus knee has a tibiofemoral angle of > 10o

 

Causes

 

Inflammatory

- RA

 

TKR Bilateral Valgus OA

 

Osteomalacia 

- rickets, renal

 

Trauma

- tibial malunion

- plateau fracture

 

Childhood

- physeal arrest

 

HTO

 

Primary OA

- most common

- females

- unresolved physiological valgus deformity

 

Pathology

 

Soft tissue abnormalities

 

A.  Contraction of lateral structures

- ITB

- LCL

- Popliteus

- PL capsule

- Lateral head gastrocnemius

- Lateral IM septum

- Long head of biceps

 

B.  Lax medial structures

 

Bony abnormalities

 

A.  LFC hypoplasia

- beware posterior condyle referencing

- cause IR of the femoral component

- use Whiteside's AP axis / epicondylar axis

 

B.  Posterior aspect lateral tibial plateau

 

Krackow Classification

 

Type 1 / Lateral bone loss

 

TKR Valgus OA Lateral Bone Loss

 

Type 2 / MCL deficient

 

TKR Valgus OA MCL Insufficiency

 

Type 3 / Secondary to HTO

 

TKR Valgus Secondary HTO

 

Surgical Problems

 

1.  Approach

 

Medial approach

 

Advantage

A.  Easy to evert patella because

- increased Q angle

- tibial tuberosity lateralised

 

Disadvantage

A.  More difficult to reach contracted lateral side

B.  If perform lateral release, risk devascularising the patella

C.  Must not perform any medial release

 

Lateral approach Keblish 1991

 

Advantage

A.  Direct access to lateral structures

- makes these easier to release

B.  Preserves blood supply to patella

 

Disadvantage

A.  Wound closure at end of case

- not enough capsule to close after correction valgus

- closing only skin and soft tissue, may need to utilise the fat pad

 

Keblish Technique

- midline incision

- lateral release along lateral border of patella

- coronal z step cut in vastus lateralis

- is 6 - 9 mm thick

- lower 50% taken off patella

- superficial 50% attached to patella

 

2.  Bony alignment

 

Rotation

- deficient LFC 

- don't use posterior condylar axis to set rotation

- use Whiteside's AP axis and epicondylar axis

- can place a osteotome under LFC when placing sizing block

 

Tibial resection

- don't take 10 mm as bone worn laterally in valgus OA

- can't take 2mm off medial side as is the normal side

- need to estimate

- take 6 mm from lateral tibia intially, stay above fibula head

- much more symmetric proximal tibial resection

- use trial blocks to assess flexion / extension gaps

 

TKR Valgus OA Tibial Resection

 

Deficient lateral tibial plateau

- don't take > 10 mm medial plateau

- will get down into soft bone

- preop plan

- may need augments laterally and therefore stems

- below xray is borderline / but just ok

 

TKR Severe Valgus Tibial Resection Planning

 

3.  Soft tissue balancing

 

Best to sacrifice PCL early

 

Tight Extension

- pie crust or release ITB 

- +/- lat gastrocneumius off femur

- +/- Z lengthen biceps

 

Tight Flexion

- PL corner

- release popliteus proximally

 

Tight Extension & Flexion

- release LCL from lateral epicondyle

- usually done last

- periosteal sleeve as per popliteus

 

4.  Management MCL Deficiency

 

A.  Young Patient

 

Tighten MCL

- advance femoral insertion (Krackow)

- cut mid-substance and imbricate (Krackow)

- take off femur with bone plug / advance

 

CCK Prosthesis

- acts as an internal splint whilst MCL heals

 

B.  Older patient

 

Consider hinged prosthesis

 

5.  Prosthesis

 

PS to aid balancing

CCK / MCL Deficient

Augments / lateral bone loss

 

5.  Patella tracking

 

Tends to track laterally after correction

- resurface / place button medially

- lateral release may be required

- issue if have done medial approach

- may get patella AVN

 

6.  CPN

 

Need to check in recovery

- splint the knee in flexion post operatively

 

Complications

 

ML instability

- release too many lateral structures

- can develop late

- incidence 6-25%

- may need CCK on hand

 

Avoid by

- pie crusting ITB

- releasing popliteus / LCL as sleeve

 

Recurrent / residual valgus

- prone to maltracking

 

Wound healing

 

Patella maltracking 

 

Patella fracture

- secondary to AVN from medial approach and lateral release

 

Stiffness

 

CPN 

- more common if valgus > 12o

 

 

Revision TKR

Complications

1.  Infection

 

Revision TKR InfectedRevision TKR Infected Bone Scan

 

Infected Revision TKR

 

Peters et al J Arthroplasty 2009

- 184 cemented revision TKR with press fit stems

- 7% revision rate for deep infection

- 4 new cases of sepsis, 9 were recurrence of sepsis

 

Management

 

Extremely challenging

- significant bone loss

 

Infection Revision TKR SpacerRevision TKR Infection Spacer

 

2.  Instability

 

Revison TKR Dislocated Hinge APRevision TKR Dislocated HInge Lateral

 

3.  Fracture

 

4.  DVT / PE

 

5.  Bleeding

 

6.  Stiffness

 

7.  Neurovascular injury

 

8.  Pain

 

9.  Extensor mechanism dysfunction

 

Revision TKR Quadriceps RuptureRevision TKR Quadriceps Rupture Lars Ligament Repair

 

10.  Loosening

 

Revision TKR Loosening Hinge APRevision TKR Loosening HInge Lateral

 

Management Bone Defects

AORI / Andersen Orthopedic Research Institute

 

T Tibial  F Femoral

 

1.  Contained Metaphyseal Defect

 

2.  Damaged Metaphyseal

A.  One Condyle

B.  Both Condyles

 

3.  Deficient Metaphysis +/- collaterals +/- extensor mechanism

 

1.  Contained Metaphyseal defect 

 

Revision TKR AORI Tibia Type 1 APRevision TKR AORI Tibia Type 1 Lateral

 

Management

 

A.  Bone graft defects

 

B.  Standard +/- Revision TKR

 

Revision TKR Type 1 DefectRevision TKR Type 1 Defect Lateral

 

2.  Damaged Metaphysis

 

A One condyle

 

B Both

 

Revision TKR AORI Tibia Type 2 B APRevision TKR AORI Tibial Type 2 B Lateral

 

Revision TKR Tibial Lysis 2BRevision TKR Damaged Tibial Metaphysis

 

Management

 

A.  Cement < 1cm

 

Revision TKR Bone Defect Cement APRevision TKR Bone Defect Cement Lateral.jpg

 

B.  Augments < 2cm

 

Revision TKR Tibial AugmentsRevision TKR Augments

 

C.  Bone graft

 

3.  Deficient Metaphysis +/- collaterals / quads

 

Revision TKR Deficient Femoral Metaphysis

 

Revision TKR Deficient Metaphysis APRevision TKR Deficient Metaphysis Lateral

 

Management

 

A.  Bulk structural allograft

- femoral head

 

Engh et al JBJS Am 2007

- bulk structure allograft in the tibia in 46 patients followed for 8 years

- 2 deep infections

- average knee society scores 84

- no graft collapse or loosening

 

B.  Tantalum cones metaphyseal filling / Trabecular metal

 

Revision TKR Tantalum APRevision TKR Tantalum Lateral

 

Meneghini et al JBJS Am 2009

- tantalum porous tibial implant in 15 pateints followed average 3 years

- AORI type 3 and type 2B

- knee society score average 85

- all had evidence osteointegration, no loosening

 

Howard et al JBJS Am 2011

- femoral tantalum components in 24 knees followed for averag 3 years

- knee society score average 81

- all well fixed with no complications

 

C.  Mesh + impaction bone grafting

 

D.  Tumour prosthesis / Custom implants

 

Revision TKR Tumour ImplantRevision TKR Tumour

Planning

IndicationsRevision TKR

 

Aseptic loosening

Infection

Instability

Wear & breakage components

Fracture

Stiffness 

Pain

 

Aims

 

Restoration of anatomical alignment

Restoration of joint line

Restoration of bone stock

Restoration of femoral and tibial rotation

Flexion and extension balancing

 

Surgical Issues

 

1.  Exclude Infection

2.  Incisions / Approach

3.  Component removal

4.  Bone Defects 

5.  Restoration of joint line

6.  Balancing

7.  Component Fixation / Stems 

8.  Constraint

9.  Patella

 

Examination

 

Lower limb

- old incisions

- pulses

- sensation (Charcot neuropathy)

 

ROM 

- need 110o flexion to remove and insert components

- otherwise will need tibial tubercle osteotomy

 

Stability

- LCL / MCL intact

- need VVC / hinge

 

Extensor Mechanism

 

Examine hip and back

- may be cause of referred pain

 

Exclude Infection

 

1.  Clinical Findings

2.  ESR & CRP

3.  Bone Scan

4.  Aspiration 

5.  Intra-op FFS

 

Assess Bone Stock

 

Causes

- secondary to osteolysis 

- iatrogenic when removing components

 

Site

 

Tibial bone loss

- often medial, due to implant in varus

 

Femoral bone loss

- often posterior femoral condyles

 

Aims

 

Preserve all viable bone

Reconstruct deficient bone

Provide stable base for implants

 

AORI Classification / Andersen Orthopaedic Research Institution

 

T Tibial F Femoral

 

1 Contained Metaphyseal defect 

 

2 Damaged Metaphysis

A One condyle

B Both

 

3 Deficient Metaphysis +/- collaterals / quadriceps

 

Template

 

1.  Establishment of joint line essential

 

Allows flexion and extension balancing

 

X-ray contralateral knee

- measure medial epicondyle to joint line

 

Template same on revision knee

 

2.  Length and diameter of stems

 

3.  Augments

- distal and posterior femur

- proximal tibia

 

Order instrumentation

 

Previous component company specific removal gear

Cement removal instruments

Diaphyseal engaging stems, offset available

Modular metal augments

Constraint including CCK / hinges

Full component of poly thicknesses

Allograft

 

 

 

 

Stems

Advantage

 

1.  Reduce implant loosening

- offset load sharing to diaphysis

- 30% if > 70 mm

 

2. Restore optimal alignment

 

Indications

 

1.  Using augments or bone grafting

 

2.  Increased constraint 

- VVS / hinge

 

Types

 

Uncemented

Cemented

 

Press fit uncemented

 

Design

- cemented in metaphysis and condyles

- uncemented in diaphysis

- need to engage diaphysis

- often need offest options from tibial tray

- this is so can implant stem in correct position

 

Revision TKR Uncemented Femoral StemRevision TKR Uncemented Tibial Stem

 

Advantage

- easy to use

- suit IM system of alignment in revisions

 

Disadvantage

- no surface treatment / no ingrowth

- often don't completely fill canal

- can force implants into position of malalignment

- end of stem pain

 

Peters et al J Arthroplasty 2005

- 50 TKR with uncemented stems

- 1/50 (2%) reported thigh pain

- 1/50 (2%) reported leg pain

 

Cemented

 

Advantage

- increased area of fixation

 

Disadvantage

- less guidance for IM alignment

- hard to remove all cement if need to

 

Revision TKR Cemented Stems LateralRevision TKR Cemented Stems

 

 

 

 

Surgical Technique

ApproachRevision TKR Tibial Lysis

 

Incision

 

Always use the most lateral scar

- blood supply comes from medial aspect

- want to avoid a large lateral flap of dubious quality

- cross transverse scars at 90o

- minimum 7 cm skin bridge

 

Options

- can do trial / sham incision down to capsule

- can perform skin expansion prior to surgery

- consider plastic surgical review for muscle flap

(medial gastrocnemius rotation flap)

 

Approach

 

Excise scar tissue

- recreate medial and lateral gutters

- recreate suprapatellar bursa

 

Patella eversion

- can just slide patella off laterally rather than evert

- put pin in tibial tuberosity to protect patella tendon insertion

 

Extensile exposures

 

1.  Quadriceps snip

 

2.  Quadriceps turndown

 

Rarely used

- risk AVN of patella

 

May consider if limited flexion

- lengthen quadriceps tendon

 

3.  Tibial tuberosity osteotomy 

- 6-10 cm long, 2 cm wide, 1 cm thick

- lateral periosteum intact / lever open laterally

- bypass osteotomy with stem

- need to wire back around the tibial stem

- place wires before definitive stem

- drill holes medially and laterally

- can use diverging screws as well

 

Removal of components

 

Remove poly

- implant specific tools

 

Careful removal implants to minimise bone loss

- thin, flexible osteotomes, micro-sagittal saw

- gigli saw

- can cut metal with carbide burr

 

Cemented femur / tibia

- separate at cement-implant interface

- remove cement later

 

Uncemented femur / tibia

- rarely have to cut base plate from keel (carbide burr)

- can perform TT osteotomy

- stacked osteotomes

 

Prepare Tibia

 

Reason

- sets joint line

- enables flexion extension balancing

 

Insert trial intramedullary stem

 

Find IM canal

- ream until appropriate diameter

- desired length

- place trial 

- set proximal cutting jigs off IM stem

 

Proximal tibial cut

 

Minimal tibial cut

- cut 1 - 2 mm off high side to preserve bone

- usually lateral side

- make resection for desired augment (5 or 10 mm) other condyle

- use jig

 

Insert trial tibia

 

Use offset as required

- ensures tibial component good fit on tibia

- tibial component not dependent on stem position

- ensure not internally rotated

- attach required augments

 

Recreate Joint line

 

Importance

- if rebuild tibial with augments and poly to correct joint line

- can rebuild distal and posterior femur to match

 

Revision TKR Severe Loss Tibial Bone StockRevision TKR Tibial Augments

 

Markers

- scar from meniscal remnant

- 10 mm above fibula head

- 30 mm below medial epicondyle

- use templated distance from medial epicondyle on other knee

 

Restore joint line with appropriate sized poly

 

Prepare Femur

 

Insert trial intramedullary stem

 

Find IM canal

- entry point important

- if too posterior will flex femur

- if too anterior will extend femur

 

Revision TKR Anterior Femoral Stem Entry

 

Ream until press fit

- insert desired length of stem

 

Distal femoral Cut

 

Distal cutting block on stem

- want to freshen surfaces minimally

- 1-2 mm off distal surface only

- consider distal femoral augments

- wait to trial extension gap to decide distal femoral augments

 

AP sizing

 

Posterior femoral condyles frequently deficient

- require augment posteriorly

- use anatomically sized femoral component

- template from other knee or use previous size from primary

- add augments posteriorly as

 

May need offset so femoral component sits on IM stem

 

Revision TKR Offset Femoral Stem

 

Rotation

 

Trans-epicondylar axis most reliable

- posterior femoral condyles may be more deficient laterally than medially

- set correct rotation

- freshen AP and chamfer cuts

 

Balancing

 

1.  Loose flexion and extension

- ensure poly thickness restores correct joint line

- increase distal and posterior femoral augments

 

2.  Loose flexion gap

- most common

- add posterior femoral augments

- use appropriate sized femoral implant

 

Revision TKR Posterior Femoral Augments

 

3.  Loose extension gap

- increase distal femoral augments

 

Distal Femoral Augment

 

4.  Tight flexion gap

 

A.  Reduce femoral distal augments / femoral component size

B.  Lower joint line by reducing poly thickness

- becomes loose in extension

- increase distal femoral augments

 

5.  Tight extension gap

 

A.  Correct joint line

- decrease distal femoral augments

B.  Joint line too high

- reduce poly to joint level

- create loose flexion gap, posterior femoral augments 

 

6.  Tight flexion and extension

- reduce poly thickness

 

Constraint

 

Usually determine constraint after bone defects dealt with and flexion / extension gaps balanced

 

1.  Collaterals Intact

 

Posterior stabilised sufficient

 

Revision TKR Posterior Stabilisation APRevision TKR Posterior Stabilised Lateral.jpg

 

2.  MCL deficient

 

Option A

 

Young patient MCL deficient

- High Post / Condylar constrained implant

- will eventually fail if don't reconstruct MCL

- young patient use CCK as internal splint and reconstruct MCL

 

MCL reconstruction

- achilles tendon allograft

- semitendinosus left attached distally

 

Option B

 

Rotating hinge 

- elderly patient MCL deficient

 

Revison TKR Hinge APRevision TKR Hinged Lateral

 

TKR HingeTKR Hinge

 

3.  Lateral instability

 

Causes

 

1.  Femoral component malrotation

 

2.  ITB deficient

- VVC

- brace for 3/12

 

3.  LCL deficient

- VVC + reconstruction

- semitendinosus / lars / allograft

- find centre of rotation on femur

- pass through drill hole in fibula

 

Patella 

 

Options

 

1.  > 10 mm bone remaining

- can resurface

 

2.  Ignore

 

Revision TKR Non Resurfaced PatellaRevision Patella

 

Patella tendon avulsion

 

1.  Repair

- Krackow suture secured around tibial post and washer

- staples

 

2.  Biological augmentation

- semitendinosus graft and gracilis

- achilles allograft

- LARS
 

3.  Immobilise in extension for 6 weeks

 

Revision TKR Staple Patella Tendon Insertion

Unicompartmental Knee Replacement

Background

AimUKA Oxford AP

 

UKA is intended to be load sharing

- correct to neutral or slight varus

 

HTO is a load-shifting / load-sparing procedure

- over correct into valgus

 

UKA v TKR

 

Advantages UKA

 

1.  Rapid rehabilation

 

2.  Increased ROM

 

3.  More normal knee kinematics

- more normal gait

- preserves ACL, PCL, PFJ & lateral compartment

 

4.  Low complication rate 

- decreased infection, bleeding

 

Results

 

Laurencin  Clin Ortho 1991

- TKR one side, UKA other

- patients preferred UKA

 

Newman JBJS Br 1998

- randomised trial TKR v UKA

- UKA less perioperative morbidity, faster ROM, better knee scores

 

Disadvantages UKA

 

1.  Technically difficult

 

2.  Progressive OA of un-resurfaced compartments

 

3.  Inferior survivorship to TKR 

- higher revision rates in young

- revision rates in Australian Joint Registry approach TKR only in > 75 year old patient

 

4.  More difficult future TKR with poorer results

- revision rate of TKR post Uni is close to 10% 5 year in AJR

 

UKA v HTO

 

Advantages UKA

 

Fewer complications

- higher earlier success rate

- more rapid rehabilitation

 

Stukenborg et al Knee 2001

- randomised prospective

- 7 - 10 year survival

- 77% UKA

- 60% HTO

- higher complication rate in HTO

 

Indications 

 

Kozinn and Scott JBJS Am 1989

- minimal deformity

- only medial compartment OA

- asymptomatic mild PFJ OA

 

Unicompartmental OA +

- intact ACL 

- FFD < 5°  

- flexion > 90° (probably more, 110-130o)

- maximum varus 15o which is correctable to neutral

- older age group (> 60 years) 

- lower weight < 82 kg

- lower activity level

 

Only 6% of patients fulfil these criteria

 

Contraindications

 

Instability

- ACL deficiency

- tibial / joint subluxation

- lateral thrust

 

If ACL gone allows varus in all positions  

- subsequent global joint erosions

 

Significant OA changes in other compartment

- some surgeons ignore PF if non symptomatic

- only early changes in lateral compartment

- examine at time of surgery

 

Inflammatory arthritis

 

Assessment

 

One finger test

- patient points to affected compartment only

 

X-rays

 

AP / Lateral / Skyline

 

Patient 1

 

UKA Preop AP 1UKA Preop Lateral 1UKA Preop Skyline 1

 

Patient 2

 

UKA Preop AP 2UKA Preop Lateral 2UKA Preop Skyline 2

 

Surgical Principles

 

1.  Correct to neutral or slight varus

 

2.  Femoral component 

- should be centred on condyle 

- parallel to tibial component

- must not overstuff

- must not impinge on patella

 

3.  Tibial component 

- minimal resection

- must be perpendicular to long axis tibia

- must not be in varus

- should cap but not overhang medial cortex to prevent irritation of pes anserinus

 

4.  Balance flexion extension gaps

- don't overstuff with poly

- 2mm laxity in flexion and extension

 

Prosthesis

 

Oxford

 

UKA Oxford APUKA Oxford Lateral

 

Design

- spherical, constant radius femur, fully congruent

- mobile bearing (risk bearing dislocation)

- flat tibia

 

Variations on Oxford design

- fixed bearing

- all poly tibia

- uncemented tibia + screws

 

UKA Unix APUKA Unix Lateral

 

Complications

 

1.  Bearing dislocation

 

2.  Poly wear

 

UKA Bearing Dislocation

 

3.  Pes anserine bursitis

 

4.  Patella impingement

- femoral component not flush in sagittal plane

- don't oversize femoral component

 

5.  Aseptic loosening

 

Cause

- no difference fixed v mobile bearing

- undercorrection of deformity

- malalignement of components

 

UKA Tibial LysisUKA Malaligned Femoral ComponentUKA Loosening

 

6.  Tibial Subsidence

- too much bone taken from tibia (into soft bone)

- overimpaction of tibial component

 

UKA Tibial Subsidence

 

7.  Progressive OA

- overcorrection of deformity overloads lateral component

- degeneration of PFJ

 

UKA Developing Lateral OAUKA developed PFJ OA

 

8.  Infection

- 0.8% UKA

- 2% TKA

 

Results

 

UKA

 

Price and Svard AAOS 2000

- Oxford Knee

- 95% 10 year survival

 

Swedish knee registry

 

90% survival at 5 years

- failure rate varies 0 - 30% in different centres

 

Australian Joint Registry

 

12.1% revision rate at 7 years

- 3 times the revision rate of TKR

 

Risk of revision decreases with age

- < 55 20% 7 year revision

- > 75 6% 7 year revision

- but worse than TKA for all ages and gender

 

Prosthesis

- Oxford 11.5% 7 year revision

- LCS 20.4% 7 year revision

 

Revision of UKA to TKA

- 12.9% 5 year revision of that TKA

- 3.5 x primary TKA

 

Summary

- joint registry has poor results

- specialised centres have good results

- need to carefully select patients

- be an experienced unicompartmental surgeon

- perform good surgery

 

Lateral Unicompartmental Knee

 

Gunther et al 1996 with 53 Oxford knees

- 75% seven-year cumulative survival rates

- main problem was with dislocation of bearing

 

Findings

- suggest poorer results with lateral replacements

- suggests fixed bearing may be more suitable in lateral compartment

 

Conversion to TKR

 

UKA Preop Revision APUKA Preop Revision Lateral

 

Problem is bone loss

- up to 75% need grafting / augments

- need to take minimal bone at primary surgery

- watch closely for signs osteolysis

 

Results

- worse if need augments / stems

 

UKA Revision to Long Stem TKRUKA Revision To TKR Lateral

 

 

 

Oxford Technique

PreoperativeUKA Oxford AP

 

Indications

- anteromedial disease

- patient points to anterior medial joint line only as source of pain

 

Pre-op x-rays

- AP and lateral

- Rosenberg to assess lateral joint

- long leg AP view to assess alignment

 

Pre-op examination

- must correct to neutral

- no releases are performed in a UKR

 

Operation (Oxford Meniscal Bearing)

 

Set up

- leg hangs over thigh bolster

- must be able to flex to 110o

- have bolsters on bed ready to change to TKR if required

 

Incision

- medial border of patella along medial border of patella ligament to medial border of TT

- this gives good exposure of medial compartment

- remove fat pad that is blocking view and meniscus

- inspect ACL, PFJ and lateral compartment to decide whether to proceed

- remove tibial / femoral / notch osteophytes

 

Tibial cut

- tibial EM jig

- centred over crest and second metatarsal

- depth of cut is very important as too much exposes weaker tibial bone and makes any revision more difficult

- usually takes 5 - 6 mm off the preserved posterior portion of the medial compartment

- this will mean that after insertion of a 2 mm tibial prosthesis, the insert should be 4 -5 mm thick

 

Vertical cut

- along the lateral margin of the MFC, medial edge of ACL

- ensure is passed completely posterior

- inferiorly is limited by tibial block

- want to ER the cut, as the mobile bearing will come laterally in extension

 

Horizontal cut

- protect MCL with retractors

- bony cut should come out as one piece

- trial off the inferior aspect of bone piece with opposite side trial

 

Posterior femoral cut

- femoral IM rod I cm anterior to notch and 5 mm medial towards femoral head

- this retracts patella, and guides flex/ext of femoral component and rotation

- insert tibial spacer to reconstitute tibial joint line

- insert femoral jig

- align with crest of tibia for varus / valgus, make parallel with femoral rod for flexion/ extension, and aligned with IM rod for rotation

- insert 2 x drill holes

- attach jig

- cut posterior femoral cut

- can now see better and remove all meniscus

 

Setting flexion / extension gaps and cutting distal femur

- insert 1 sphigot and ream

- in flexion insert spacer block (about 5 - 6 mm)

- in 20o extension insert spacer block (about 1 - 2 mm)

- the difference is how much more you have to remove from the distal femoral cut to balance gaps

- if difference is 3 mm, insert 3 sphigot and ream (has a stop)

- retrial gaps

 

Preparation of femur

- insert trials

- extend knee

- will see that need to remove portion of cartilage above femoral component to prevent poly impingement

- need to remove cartilage below implant

 

Preparation of tibia

- insert appropriate trial

- use special instrument to insure is flush posteriorly

- able to overhang 1 - 2mm antero-medially

- better to oversize than undersize to prevent tibial subsidence

- pin in place

- need to cut for keel

- must not penetrate anterior or posterior cortex or risk of fracture is too high and will need to convert to TKR

 

Cement prosthesis

 

Retrial

- trial spacer blocks to determine final size of meniscal bearing poly

- not too tight as don't want to overcorrect out of varus and overload the lateral compartment