A Assessment


ACL Normal ArthroscopyACL Normal Arthroscopy




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 




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




In full extension ACL

- subtends 45o angle in sagittal plane

- 25o angle in coronal plane



- 25-40 mm long

- 7-10 mm wide




Anteromedial and posterolateral bundles

- described regarding point of tibial insertion



- smaller

- tight in flexion

- test with anterior draw



- larger

- tight in extension

- test with Lachman / Pivot Shift



-  posterior articular nerve / branch tibial


Arterial supply 

- middle geniculate   



- medial wall LFC

- semicircular

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



- 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




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




1:1500 - 1:3500




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



- 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



- 10-20%




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




Laxity Grading Lachmans / Anterior Draw


1+: mild instability < 5mm

2+: moderate instability 5-10mm

3+: severe instability >10mm




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



- ACL torn

- lateral tibia subluxed anteriorly in extension

- reduced in flexion



- knee moves from extension to flexion

- valgus force applied to knee

- apply axial load

- mimicking weight bearing



- 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




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




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




Normal ACL on MRI


 Intact ACL T2Intact ACL T1MRI Normal ACL



- 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



- 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




ACL Partial Tear ArthroscopyArthroscopy Empty Lateral Wall


ACL Rupture Empty Lateral WallRuptured ACL



- empty lateral wall

- ACL healed onto PCL

- partial tears

- ACL healed onto different part of LFC

B Management Options



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




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



- 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



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

- higher in BPTB ligament


Non-operative Management




Patient able or willing to modify activities

No functional instability




Acute phase


RICE, Analgesics

Weight bear as tolerated 


ROM exercises started early

- aim to regain full flexion & extension early



- started once FROM achieved

- quads & hamstring

- closed chain exercise


Resumption of sport


ACL rehabilitation protocol



- 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




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




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 



- inability to flex / extend knee

- due to flipped bucket handle meniscus



- ACL stump causing FFD

- arthroscopy to remove blockage



- Confirm locked bucket handle meniscal tear


Need to unlock knee




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




Grade II MCL

- 75% chance ACL rupture




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




Surgical Options


1.  Primary Repair


High failure rate



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



- 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



- 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




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




Potential Advantages

- stiffer / perhaps increased strength and stability in contact athlete

- potentially better fixation because of bone blocks



- 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



- little functional deficit

- mild knee flexion weakness

- less PFJ pain



- ? more post operative laxity

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



- generalised ligamentous laxity

- sprinters

- hamstring injury


Hamstring v BPTB




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



- achilles


- quads tendon

- tibialis anterior / posterior



- nil graft site morbidity



- disease transmission 

- high costs ($5000 per graft)

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

- increased failure rate




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



- revision

- older, lower function patients


4.  Synthetic



- no donor site morbidity



- poor history with regards rupture and synovitis




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



- cannot damage MFC


Potential disadvantage

- tibial tunnel sets position of femoral tunnel

- tends to make the graft more vertical



- drill femur with knee at 90o


2.  Anteromedial portal



- allows separation of femoral from tibial tunnel

- can place femoral tunnel lower on femoral wall


ACL Anteromedial Femoral Tunnel



- places drills and reamers close to MFC

- must be careful not to damage cartilage



- must hyperflex knee

- or femoral tunnel may exit in PFJ


Femoral Tunnel Back wall blow-out




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




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




ACL Large Notch OsteophyteACL Post Notchplasty



- 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



- notchplasty can lateralise

- important to only debride anterior portion of notch

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



- 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




Aperture Fixation


Interference screw

- metal / bioabsorbable


Suspensory Fixation





ACL Transfix Pin


Fauno et al Arthroscopy 2005

- compared transfix and endobutton

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





- biomechanical studies in tibia with hamstring

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



- probably more important than diameter in hamstring

- has been demonstrated than increasing length increases fixation

- increase number of threads available for fixation



- 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




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



- technically difficult

- twice as many tunnels to get wrong

- longer surgical time

- difficult revision

- no proven advantage clinically




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



Multi-ligament injury

Older patient




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



- 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




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




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



- 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




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




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




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



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



- 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



- 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



- 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




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




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




Tibial tunnel

- as above


Femoral tunnel

- pass beath pin

- drill line to line for graft size

- usually 25 mm long


Pass graft


Insert screw



- 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



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

Lars ACL



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




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




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



- 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




- 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



Back wall blow out




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



- Regain full ROM



- resolve swelling

- normal gait


2. Acute Phase 0-2 weeks post operative



- obtain full ROM




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



- resume normal gait and range

- obtain full flexion



- 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 



- return to sport



- 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




Minimum 6 months




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




Reasonable to use brace for 2 years post ACL reconstruction


ACL Brace Donjoy Defiance






F Complications


- haemarthrosis


- infection


Swollen Knee Post ACL


Septic Arthritis


Infected ACL ClinicalInfected ACL




Extremely low




Vertullo et al Arthroscopy 2012

- eliminated incidence of deep infection by wrapping graft in vancomycin



- graft salvage / multiple washouts and synovectomy

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




Early onset OA in young person


Infected ACL APInfected ACL Lateral





- 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



- 50% need no further procedures





- 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



- intercondylar notch fibrous proliferation

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

- anterior to tibial tunnel

- 5-10% of patients



- 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



- arthroscopic resection of cyclops lesion


Graft rupture


Failure rate

- 10% over life of graft

- 1% per year





- 10 - 20% post single bundle surgery

- return to sports rate 60-70%

- may be reduced in experienced surgeons



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




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



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



- 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



- 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




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 infection

- history arthrofibrosis

- has knee ever been good or always unstable

- was it good then traumatic injury







- 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




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




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)




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






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



- screw if posterior wall remains

- otherwise endobutton

- can tie over screw on femur if need to 



- usually scew +/- post


6.  Secondary restraints


A.  Posteromedial instability

- reconstruction / advancement


B.  Posterolateral

- valgising HTO

- reconstruction






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)




Usually healthy woman age 60+ years

- sudden onset of severe knee pain with normal Xray




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 




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




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



- focal increase in uptake on one side of joint 

- if tibia and femur more likely OA




May be normal in early stages



-  low signal areas in subchondral region 


SONK MRI Sagittal



- low signal

- surrounding high intensity signal secondary to oedema




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




Non Operative Management




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




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



- 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




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





- 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




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




Secondary osteonecrosis


Knee AVN 1Knee AVN 2



- Steroid Therapy (90%)

- Alcohol


- Sickle Cell Disease

- Diver's / Caisson's

- marrow proliferative disorder

- chemotherapy




Gradual onset of pain

- lateral condyle in 60%

- younger patients, mid 30's




Bilateral in 50%

- 70% have other joints involved




More extensive involvement through knee


Operative Options



- 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









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



- cannot sit on airplane toilet with door closed




Coapt 2 coplanar cancellous surfaces under compression with rigid fixation




Septic arthritis

Salvage failed TKR / infected TKR


Charcot Join





Bilateral knee fusion

Ipsilateral hip fusion




Fusion rates

- can be difficult to obtain fusion


Difficulties mobilising

- give patient trial in cylinder cast




Short leg

- fuse straight 


Normal length

- in 10° for swing through


Valgus 5 - 7o


External rotation 5 - 10o




1.  External fixator

2.  IMN

3.  Double plating




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



- simpler

- less blood loss

- better in infection



- pin tract infection, loosening




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



- 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




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



- 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



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

- different sizes for femur and tibia

- single knee incision



- very difficult to remove after fusion





Chondral Defects

Chondral Defect Medial Femoral CondyleKnee OCD Arthroscopy Type 4




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




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



- 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




Chondral Defect Full Thickness






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



- 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




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



- 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



- 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



- young patient

- contained defect

- best results < 2 cm2

- BMI < 30

- age < 40

- need cartilage on each side to contain clot



- 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




Patients may feel catching of perpendicular edge

- will resolve over time


Swelling common for 6-8 weeks




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






Transplant living viable cells

- capable of synthesising and maintaining a cartilaginous matrix

- makes a substance physically and histologically similar to hyaline cartilage



- cells presented on a membrane for implant

- ACI have to harvest periosteum to secure cells in place




Nil instability

Nil malalignment




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



- 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



- 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



- 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



- 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)



- 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




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






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




Bartlett et al JBJS Br 2005


- 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




Take bone plugs on bone and cartilage

- implant in defect

- get coverage with normal hyline cartilage

- also deals with bone defect




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



- 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




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




Very large, non contained defects

Restore anatomic contour

Nil donor site morbidity


Viable chondrocytes


Fresh grafts

- 70% viable

- None on frozen, irradiated grafts





- 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




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




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



Most common lower limb neuropathy




Valgus TKR - 3%


HTO - 10%


Direct Trauma / Compression


Knee Dislocation


Tibial fracture


Cast / Dressing


Lateral Meniscus Repair




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



- 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



- 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



- 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




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 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




Some authors report resolution of palsy if left long enough



- 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




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




Ozkan et al J Reconstr Microsurg 2009

- 34/35 achieved DF to or above neutral


Diagnostic Dilemmas


1.  No anterior / lateral / posterior compartment working




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




A.  CPN knee

- normal short head biceps EMG


B.  CPN higher

- abnormal short head biceps EMG


3.  No posterior compartment




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




A.  Spine

- S1 compression


B.  Compartment syndrome


5.  No Anterior




A.  Compartment syndrome


B.  Deep peroneal injury





High Tibial Osteotomy


Aetiology Unicompartmental OAKnee Medial Compartment OA





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 




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




4.  Posterolateral instability with varus knee

- a PLC reconstruction in setting of varus knee with fail


5.  Chondral grafting MFC




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)




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




Assumes primary cause of unicompartmental OA is 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




Lateral Closing Wedge HTO

Medial Opening Wedge HTO


Lateral Closing Wedge Osteotomy


HTO Lateral Closing Wedge



- large area cancellous bone under compression

- inherent stability

- good union rates

- early weight bearing

- quadriceps provide compression



- 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



- 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



- relatively unstable

- risk loss of fixation

- delayed / non union


- 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






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




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


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



- 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)




A.  Intra-articular


HTO Closing Wedge Intra-articular fracture


Occur in opening or closing wedge



- proximal fragment too small

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



- 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



- don't penetrate medial lateral side

- slow correction

- after plastic deformity / not fracture



- 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




Can complicate future TKR

- difficult to manage

- essentially have infected fracture

- principles of control infection / maintain stability / obtain healing




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



- anterior knee pain

- subsequent TKR difficult


Also seen in anterior wedge



Conversion HTO to TKR



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)




3.  Patella Baja



- 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





- 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




Rickets / osteomalacia




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




1.  Medial closing wedge HTO



- anatomic axis <12° valgus

- hoint line < 10°


2.  Distal femoral osteotomy



- > 12o valgus

- ? any valgus malignment requiring osteotomy

- > 90o flexion

- < 150 FFD



- medial closing wedge

- lateral opening wedge



- 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




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



- 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



- 6/52 TWB in ROM brace 

- full ROM




Wang et al JBJS Am 2005

- 25/30 satisfactory result (83%)


Lateral Opening Wedge Femoral Osteotomy



- technically much more simple than opening wedge



- lengthen leg

- higher risk of non union


Distal Femoral Osteotomy Guide wireDistal Femoral Osteotomy Puddhu Plate



- 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



- 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



- 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



- 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



- 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)



- 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



- medial

- close to midline to incorporate into later TKR

- elevate pes and MCL, close later



- 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



- 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



- 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




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



1.  Anterolateral


Viewing portal

- 1cm lateral to patella tendon

- 1cm above joint line

- 1 cm below inferior pole patella



- too medial, in fat pad

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

- too low, damage anterior horn meniscus




- 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



- just lateral to quadriceps tendon

- 2.5 cm above SL corner of patella



- evaluate PFJ

- drainage portal

- resection plicae

- removal loose bodies


4.  Posteromedial portal 



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



- 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



- anterior to medial head gastrocnemius

- posterior to MCL / MFC

- superior to pes



- posterior horn tears MM

- loose bodies

- PCL reconstruction / posterior tibial joint line debridement



- saphenous nerve


5.  Posterolateral Portal



- distend joint with fluid

- knee at 90o



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

- 2cm above joint line

- behind LFC


Knee Posterolateral Portal



- behind LCL

- anterior to lateral head gastrocnemius

- between ITB and biceps



- repair posterior lateral meniscus





6.  Accessory far medial and lateral portals


2.5 cm medial and lateral to standard anterior portals




Far medial portal

- gives good access to body of lateral meniscu

- angle is above the tibial spines


7.  Central trans-patella portal



- midline

- 1cm below inferior pole patella






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


- biceps inferiorly to protect CPN

- must dissect lateral gastronemius off capsule and retract

- protects posterior neurovascular bundle







- 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






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



- 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




2 or more ligaments disrupted

- multi-ligament knee


ACL + PCL + one of collaterals 

- knee dislocation





- 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






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




KD-IV: Both cruciates and collaterals


KD-V: fracture dislocation


N nerve C arterial


Ligament injuries



- 80% femoral avulsion

- can attempt repair



- 30% avulsion


Associated injury


Vascular injury 40%

Nerve injury 20%

Fractures 60%


Vascular Injury



- 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



- 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




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




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




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



- CT angiogram

- MR angiogram

- on table / vascular lab angiogram


CT angiogram


100% sensitive and specific


Knee Dislocation Normal CTa




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




Early to examine ligaments







Knee Dislocation MRI ACL PCL torn




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 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




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




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




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



- acute repair / reconstruct / advancement

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

- see Posterolateral Corner


2.  PCL + Posterolateral Corner



- acute repair / reconstruct / advancement




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




Knee Dislocation ACL PCL ReconstructionACL PCL Reconstruction PCL double bundle


4.  PLC / ACL / PCL



- reconstruct



- reconstruct



- repair / reconstruct


5.  ACL / PCL /  MCL



- reconstruct



- reconstruct



- 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



Hamstring ACL

Allograft for PCL

Allograft LaPrade style reconstruction for PLC




Hamstring for ACL

2 x Achilles allograft for PCL / PLC

- split one for PLC




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




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



- 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




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



Knee OA

Non Operative Management


Options / ELM POPI



Lifestyle Management

- weight loss

- reduce sport



- walking stick

- braces



- acetominophen

- glucosamine


- 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




Rosenberg view / tunnel view

- 45o flexion weight bearing view


Rosenberg View



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

- can be missed with view in extension


Knee OA APKnee OA Rosen View





- stimulates proteoglycan synthesis by chondrocytes 

- has mild anti-inflammatory properties

- however, therapeutics seems to be via PG independent mechanism




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



- harmless



- reasonably expensive

- $30 / month


Reasonable to trial and continue if works


Hylan Injections / Viscosupplementation




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





- 3 x doses



- synthetic

- single dose




$4 - 500 per treatment




In inflamed joint

- decreased concentration and MW of hyaluronan

- stimulates inflammation



- 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




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




1% risk of acute allergic reaction

- sudden swelling and pain

- treat with cortisone injection




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%




Quadriceps rehab shown to improve function without worsening arthritic symptoms


Walking Stick


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




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




Lateral heel wedge for varus knee

- shown to decrease pain in 50% patients


Arthroscopic Lavage 






1.  Removal "Chemical Soup"

- cartilage debris

- crystals

- inflammatory factors


2.  Able to treat internal derangement at same time

- chondral flaps

- meniscal tears




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





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




Deformity causing alteration of mechanical axis from knee centre


Tibial Malunion APTibial Malunion Lateral




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




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 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






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



- centre of rotation of angulation

- lines of intra-medullary canals

- intersection is CORA

- site of deformity

- best site for correction




Indications for Surgery


Varus malalignment knee / ankle

- > 10o


Valgus malalignment knee / ankle

- > 15o


Mechanical axis deviation

- > 20 mm




ActionsMedial Knee Anatomy


Primary valgus stability

- alone at 30o flexion


Secondary restraint to

- anterior translation

- to ER


Secondary medial stabilisers


Contribute in extension




- medial capsule 

- posterior oblique ligament

- medial meniscus




- 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




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



- 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




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




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 




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






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




See thickening of ligament


MCL Chronic Femoral Thickening on MRIMCL Chronic Femoral Thickening




Will see lift off of the medial meniscus


Arthroscopic Lift off of medial meniscus in MCL injury




Non operative Management



- isolated injury

- no ACL / meniscal injury

- no displaced tibial avulsion




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




Grade 1


Control pain & inflammation


- 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


- prevent full extension


6/52 in ROM hinged brace

- 30-60o for 2/52

- 30-90o for 2/52

- full range for 2/52




Marshall et al Clin Orthop 1978

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


Operative Management



- 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



- proximal laxity



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



- 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



- 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



- knee flexed to 90o, over bolster

- tourniquet

- sandbag under hip



- 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




Discoid Meniscus

DefinitionDiscoid Meniscus


Round or "D" shaped rather than crescenteric meniscus

- occupies > 70% of tibial surface

- 90% occur on lateral side





- 1:100

- usually presents in children & adolescents


Case reports of

- medial

- bilateral

- medial and lateral in same knee








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




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




Reproduce clicking at 110° flexion


Lateral joint line tenderness / mass




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 



- 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




Widened joint space


Discoid Meniscus Flattened Condyle Widened Joint Space


Flattening or cupping of plateau


Flat LFC


Hypoplastic Lateral Tibial Spine




Obviously enlarged LM

See meniscus on 3 consecutive cuts


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


Discoid Meniscus with intrasubstance degeneration






There is a protective element to lateral meniscus

- resect only if painful tear / young patient




Convert unstable meniscus to a stable contoured one




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



- 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



- 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



Most common in lateral meniscus 9:1


Peak incidence 20-40




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




Usually present with pain

- activity related


May notice lump

- can vary in size with activity




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





Cacific deposit in MCL / LCL


Soft tissue tumour




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






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




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




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





- 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



- 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



- tear of insertion of posterior horn of meniscus

- difficult to fix

- must repair down to bone



- 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



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





- meniscal extrusion

- meniscal ghost sign on sagittal (missing meniscus)


MRI Meniscal Root tearMeniscal Root Tear MRIMRI Meniscal Root Tear 3




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



- 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




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



- 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




Circumferential type I collagen fibres

- radial fibres to anchor them

- more random mesh structure at surface

- fibrochondrocytes


Blood Supply



- 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




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




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



- doesn't extend to periphery



- 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




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



- only with longitudinal tears / bucket handle tear


Giving Way

- may occur with other knee disorders

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







- 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°




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




Mainstay of diagnosis and treatment


Bone Scan


Don't forget SONK in differential

- 60 yr old female with normal x-rays

- acute onset pain



Should usually show up on MRI




Surgical Indications


Painful locking / clicking with disability

Acutely locked knee

Repairable meniscus in combination with ACL injury

Repairable meniscal injury in young




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



Subtotal Meniscectomy


Young patient

- previous total or near total meniscectomy

- developing joint line pain

- early chondral changes

- normal anatomic alignment

- stable or reconstructable knee




> Grade 2 Chondral changes


Farr et al Am J Sports Med 2007

- combined mensical transplantation with ACI

- improved patient outcomes




To prevent progressive cartilage damage




1.  Graft selection

- usually fresh frozen


2.  Graft sizing


Size needs to vary < 5% compared with original



- X-rays accurate in 79% cases

- CT scan

- MRI accurate to within 5 mm


3.  Surgical technique


Secure fixation important




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




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














- 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




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



- long standing

- irreparable



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


Compartment Syndrome Exertional,

DefinitionCompartment Release


Increased pressure within a closed fibro-osseous space




Seen in athletes, associated with repetitive exertion






1.  Anterior compartment

- anterior tibial artery

- deep peroneal nerve


2.  Lateral compartment



3.  Superficial posterior

- sural nerve


4.  Deep posterior

- posterior tibial nerve

- posterior tibial and peroneal artery




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




Anterior compartment > lateral compartment

> deep posterior compartment > tibialis posterior compartment




Stress fractures

Muscle strain

Nerve entrapment

Spinal stenosis




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




Rule out stress fracture


Bone Scan


May show diffuse uptake along tibia in some cases

- lack of uptake rules out stress fracture




Fascial defect with muscle herniation


Fascial Defect


Compartment Measures



- 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




Non Operative


Reduce activity

- NSAIDs and orthotic shoes

- not often tolerated by athletes


Surgical Decompression


Compartment Release




Depends on compartment involved

- usually anterior / lateral




Schmitz et al Int J Sports Med 2004

- open release in 56 patients

- 87% good results


Can get wound issues


Wound Issue Compartment release




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



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





- sudden increase in distance

- hill running

- genu varum 

- improper shoe wear




Point tenderness


Ober Test 

- unaffected knee and hip at 90o

- abduct hip, flex knee

- if ITB tight, unable to drop below horizontal




Xray / MRI

- exclude other diagnosis

- stress fractures

- ganglion




Nishimura et al Skeletal Radiol 1997

- swelling and oedema behind ITB

- usually the posterior portion

- no evidence of thickening of ITB


Non operative




NSAID / HCLA injections

- settle the acute phase

- allow aggressive ITB stretching






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

2.  ITB lengthening

3.  Excision ITB bursa




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






Superficial & Deep Infrapatellar




Biceps femoris - between biceps & LCL


LCL - between LCL & capsule over popliteus tendon


Lateral Gastrocnemius - between LG & capsule


Popliteus - between popliteus tendon & tibia & fibula




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




In midline and below joint line

- position crucial to avoid confusion with ST tumour




May leak or rupture

- can be very painful

- causes swollen tender calf & mimics DVT





- 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 




Enlargement of bursa

- presents betwen semimembranosus & head MG

- occurs in children & young adults




Painless lump behind knee

- inverted U shape

- medial to midline

- most prominent with knee straight


Knee joint is normal

- lump may ache




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




Resolve over 10-20 months

- 50% recurrence with excision 

- do not operate


Prepatellar Bursitis / Housemaid's knee




Due to friction between skin & patella

- occurs with repetitive kneeling




Circumscribed fluctuant swelling anterior to patella

- knee joint normal




May see calcification in long standing cases


Prepatella Bursitis Xray




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




Occurs over medial upper tibia

- deep to sartorius, gracilis, semiT

- lies between pes anserine & MCL


Pain and tenderness over insertion




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



Knee forms from 3 separate compartments


Plica represents normal embryonic synovial septum that persists into adult life




20% of knees have medial patellar plica at arthroscopy


Symptomatic plicae much less common 1-2%


Mean age 14




1.  Infrapatellar (ligamentum mucosum) 


Most common / always asymptomatic



- likely stabilises the fat pad to the knee

- may prevent fat pad impingement


2.  Suprapatellar 



- often incomplete

- may separate suprapatellar bursa from knee

- may hide loose body


2.  Medial patellar 


Least common / rarely symptomatic



- 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




Medial Parapatella Plica MRI





- thin

- no evidence inflammation

- no evidence chondral damage


Medial Plica Asymptomatic ThinMedial Parapatella Plica Non Pathological



- 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




Patient based knee score

- limp / support / pain / stability

- locking / swelling / stair climbing / squatting


< 65      poor

65 - 83   fair

84 - 90   good

> 90       excellent




Activity score

- score between 0 - 10

- 0 sick leave or disability because of knee problems

- 10 sport at national level




Internation Knee Documentation Committee

- patient based knee score

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

- variety of specific activities






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





OA - Osteophytes








Can cause chondral damage




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




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




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



- 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



- 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



Medial Tibial Stress Syndrome

- pain along the tibial origin of tibialis posterior or soleus




Pain anterior aspect of shin

- running

- soccer

- basketball




Compartment Syndrome

Stress fracture of tibia




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




May show periosteal reaction





Achilles stretching

Shock absorbing insoles

Graduated return to running




Moen et al Br J Sports Med 2011

- improved results with ECSW







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




Knee OCD Case MRI 1Knee OCD Case MRI 2


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




Probably unstable

- need to mobilise

- debride base

- bone graft

- fix securely in situe




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




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







DefinitionKnee OCD MRI Cartilage Intact


Osteochondritis Dissecans

- separation of avascular fragment of bone & cartilage




M : F = 2:1


Mean age 18 years

- can present as young as 9




Most common cause of knee loose body


There is a genetic predisposition / familial

- can be bilateral




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




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




More important in adults

- interruption of blood supply & subsequent AVN


Conflicting beliefs



- 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




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




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




History of trauma in 50%

- symptoms usually vague & poorly localised early

- most common vague ache


May be

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




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




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



- 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



- cartilage intact

- no synovial fluid behind lesion



- cartilage not intact

- evidence synovial fluid


Other Classifications





- 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 



OA / Cartilage Fragments

Synovial Chondromatosis

Menisci Tear

ACL Stump




European Orthopaedic Paediatric Study JPO 1999

- 452 patients

- juvenile and adult



- 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




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




No impact sports

Unloader brace 6/12

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


Operative Management




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




Failure non operative management > 3 - 6 /12

MRI no fluid behind lesion

Cartilage intact on arthroscopy



- suitable for stable JOCD

- probably insufficient for AOCD




Up to 10 passes

- aim to stimulate vascular ingrowth and subchondral healing





- easy to do

- violates cartilage



- 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



- technically easy



- 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




Partially detached lesion



- 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




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



- type 3 lesion

- type 4 / salvageable lesion



- open / medial parapatella approach

- arthroscopic


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



- 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




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




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



- 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




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





Arthroscopic Reconstruction PCL Technique


- 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



- 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




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




Go from 3+ to 2+ in 50%

3+ to 1+ in 50%


Avulsion Fracture Technique


PCL Bony Avulsion MRI




Can be done arthroscopically or open




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



- 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





Intact PCL





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



- <1/3 diameter of PCL

- anterior


Ligament HumphreysLIgament Wrisberg


Wrisberg Ligament

- 1/2 diameter of PCL                                                                                                          



Arterial supply


Middle genicular artery


Nerve Supply


Tibial nerve




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



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




Direct trauma

- posteriorly directed force on flexed knee

- dashboard injury



- forced knee hyper-extension


Associated Injuries


Posterolateral corner

Posteromedial corner

ACL (knee dislocation)

Can be associated with bony fragment (ORIF)




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




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




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




96-100% accurate


PCL Femoral AvulsionPCL Midsubstance tear with stretchingComplete PCL Tear


PCL Avulsion MRIPCL Posterior Subluxed Tibia




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




Tibia screw 8 x 25 mm



- 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




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



- check tibial step off is reduced

- posterior tibia in line with posterior femur at 90o


Management Options




- 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




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




1.  Repair bony avulsion

2.  Acute suture repair

3.  Acute augmentation

4.  Reconstruction


Repair Bony Avulsion





- 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




70o scope

- posteromedial / posterolateral portals

- PCL sutured above fragment and reduced



- 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



- 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



- graft choice

- transtibial v tibial inlay

- single v double bundle


Graft choice




1.  BPTB

- potential mismatch is a disadvantage

- need tendon length at least 40 mm

2.  Hamstring

3.  Allograft (achilles)

4.  Artificial




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




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



- 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



- 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



- all arthroscopic



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


Tibial Inlay Method



- 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



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

- not shown clinically

- does not take into account graft remodelling in vivo



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



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




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



- 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




1. Direct lateral blow to patella

- usually with knee partly flexed and quadriceps relaxed


2.  Indirect low energy injury




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




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



- more likely in those predisposed to instability


Reduction technique


Conscious sedation

- knee extended

- medial force on patella

- usually reduces easily

- splint




Haemarthrosis post reduction

- investigate further




AP / Lateral / Skyline

- examine carefully for loose body


Knee Xray Loose Body




Shows loose body and origin





- 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




Non operative




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





- loose body

- management of OCD Lesions

- +/- early MPFL repair




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


Patella Ostechondral FracturePatella Osteochondral Fracture Fixation


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



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




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




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


1. Medical epicondyle avulsion

- over medial epicondyle

- divide deep fascia

- elevate VMO

- identify MPFL

- repair using bone anchors


MPFL repair medial epicondyle


2.  Patella MPFL avulsion


MPFL Patella Avusion


Bipartite Patella



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




Bipartite Patella CT




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





- confirms quadriceps tendon intact

- look for increased uptake ? symptomatic


Bipartite patella MRI


Bone scan

- shown to have increased uptake in symptomatic / asymptomatic knees




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




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



Patella Chondromalacia


Softening and fibrillation of articular cartilage of patella



- softening and fibrillation often seen in asymptomatic population

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




Female adolescent

- recent increase in activity


Query on continuum to OA

May be a separate pathology




Unknown / varied





- direct trauma

- PFJ dislocation



- PFJ instability / chronic maltracking

- LPPS (lat patellar pressure syndrome)

- quadriceps imbalance

- VMO weakness




Idiopathically abnormal cartilage unable to tolerate load

- inflammatory arthritis

- recurrent haemarthrosis

- sepsis



- repeated intra-articular steroids

- prolonged immobilisation



- primary OA




Basal degeneration of cartilage at deep level

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




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




Anterior Knee Pain



- dull aching discomfort anterior knee

- cinema sign / sitting flexed generates pain

- stairs

- catch & pseudo-locking

- swelling




PFJ crepitus

- seen in 60% asymptomatic teens


Exclude malalignment




Exclude malalignment







Quadriceps exercises

Activity modification

Cut out brace & taping



- cortisone - last 2 - 6 weeks

- Hyaluronic acid - last 3 - 6 months






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


Unlikely to be a good option


Full thickness localised chondral defect


Subchondral Drilling / Abrasion




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




Lateral Release



- chronic maltracking



- tight lateral retinaclum



- tilt / lateral subluxation

- full thickness chondral lesion lateral facet


Fulkerson's osteotomy


Anteromedialisation of the tibial tubersity


TKR / PFJ replacement




DDx Anterior Knee Pain



Jumper's knee / Tendonitis



- prepatellar most common

- Pes anserinus 


Excessive Lateral Pressure Syndrome / Patella Tilt


Hoffa's Disease / Fat Pad Syndrome


ITB Syndrome





- RA

- Synovial Chondromatosis

- Meniscal tears


- 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 



- 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



Hoffa's syndrome

- impingement of the fat pad with knee ROM





Diagnosis of exclusion




May be more prevalent in patients with intact ligamentum mucosum




Hoffa's sign

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

- extend knee

- will cause impingement



- behind patella tendon into fat pad

- will relieve pain




See increased signal in fat pad


Fat Pad Impingement MRIFat Pad Impingement 2




EpidemiologyPatella OA Medial Facet


1 in 10 patients with symptomatic knees have isolated PFJ OA





Repetitive deep flexion


Lateral patella tightness

Blunt trauma




Anterior knee pain

- rising from chair

- ascending stairs






Patella tilt




Tender patella

- especially lateral facet


Pain with movement PFJ




Laurin View

- assess tilt


Patella OA Tilt


Merchant view

- assess subluxation


Patella OA Subluxation




Patella OA Lateral




PFJ OA ArthroscopyPFJ OA Arthroscopy


Patella Grade 4 ArthroscopyPatella Trochela Grade 4 Damage




Non Operative




- glucosamine


Cut out braces



- hydrotherapy




1.  Lateral release



- lateral tilt

- lateral facet OA

- lateral retinacular tightness

- limited goals


Patella Tilt Moderate OAPatella Tilt Moderate OA MRI


Lateral release




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




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




Oblique osteotomy 45˚

- enables antero-medial transfer of tibial tuberosity

- unloads the PFJ and the lateral facet simultaneously


Fulkerson Osteotomy APFulkerson Osteotomy Lateral




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



- previous fracture

- isolated OA to one facet



- 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




Paulos et al Arthroscopy 2008

- arthroscopic lateral release and partial lateral facetectomy

- 80% very satisfied or satisfied


4.  Patellectomy



- doesn't completely relieve pain (leaves trochlea)

- extensor weakness and lag / problems with stair descent



- 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




Good results in 

- OA from trauma without malalignment


Poorer results in OA from unknown cause

- risk developing femoro-tibial OA

- need revision



- isolated PJF OA

- < 60 years old




Inflammatory conditions

Patella maltracking and malalignment

Tibiofemoral arthritis / medial or lateral joint pain




Correct large Q angles preop with TTT

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




PF instability

Progressive tibio-femoral degeneration

Loosening rare (< 1%)




Avon (Stryker)

LCS (Depuy)




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



- progression of disease 35%

- loosening 21%

- pain 11%


6.  TKR


Patella Baja

Patella Baja







- trauma

- post ACL reconstruction / TKR

- chronic quadriceps rupture




Decreases ROM

Associated with early OA of the PFJ




Blackburne-Peel ratio at 30 degrees flexion


Patella Baja Blackburne Peele




Excise lower third patella tendon

Patella tendon reconstruction with achilles tendon allograft

Tibial tubercle osteotomy and proximalization



Proximalization fo the tibial tuberosity


Proximalization of Tibial tuberosity 1Proximalization tibial tuberosity 2


Patella BajaPost proximalization tibial tuberosity

Patella Fracture



Direct blow

- most common



- forced knee flexion with foot fixed / maximally contracted quadriceps




1.  Vertical


Patella Fracture Vertical


2.  Transverse


Patella Fracture DisplacedPatella Fracture Displaced AP


3.  Burst / Stellate


Patella Fracture Stellate




Non operative





- biomechanically stable


Undisplaced transverse fractures

- < 2mm

- extensor mechanism intact

- able to straight leg raise


Patella Fracture TransverseUndisplaced patella fracture






Displaced transverse fractures




1.  TBW


Patella TBW LateralPatella TBW AP


2.  Cerclage wire +/- ORIF

- stellate fractures


3.  Lag screws


4.  Patellectomy



- unreconstructable fracture



- 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



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 




Usually lateral


Medial is usually iatrogenic

- excessive lateral release

- lateral release for incorrect reasons

- overtightening of medial structures






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




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 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)



- patella alta / baja

- trochlea / patella hypoplasia / dysplasia 


Soft tissue

- VMO atrophy / medial retinaculum laxity / torn MPFL

- tight lateral structures (capsule, retinaculum, ITB)

- ligamentous laxity



- femoral anteversion

- external tibial torsion

- genu valgum






Beware unrelenting pain

- chondral damage

- patella tilt / lateral patella syndrome




Traumatic vs. atraumatic onset

Direction of instability 

Age first dislocation

Subsequent dislocations

- mechanism, frequency

- ? voluntar

Treatment to date 






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




1.  Squinting patella

- with femoral anteversion patellae point inwards when standing


2.  Grasshopper eyes

- patella sits high & lateral due to patella alta




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)



- 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



- 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



- line from ASIS to centre of patella 

- line from centre of patella to tibial tuberosity

- angle subtended is Q angle 



- 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




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



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



- 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



- 45o

- shoot throught film


Look for


- bony avulsion MPFL


MPFL Bony Avulsion


2.  Laurin view / patella tilt



- 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



- 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




Patella non SubluxedPatella Medial Congruence Angle




Patella Lateral SubluxationPatella Lateral Congruence AnglePatella Subluxation


4.  Trochlea dysplasia




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




1.  Skyline View


Assess for

- lateral tilt

- subluxation

- trochlea dysplasia


PFJ Axial CT


2.  Lateralisation of tibial tuberosity




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




Articular Cartilage Damage

MPFL integrity


Loose Bodies


MPFL Femoral Tear




Assess chondral surfaces

Removal of Loose Bodies


- not particularly valid

- patient is relaxed / knee filled with fluid


Non-operativePatella Instability MPFL and TTT AP




90% respond 

- very important

- 6 - 12 months minimum before offering surgery




1.  Stretches

- quads stretches


- 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






For failure of non-operative treatment 

- patella tilt with lateral patella pain

- recurrent instability




Depends on pathology

- assessment and investigation critical for deciding treatment


1.  Isolated Patella tilt



- clinical and xray patella tilt

- no instability / malalignment

- excessive lateral pressure syndrome




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




McGinty et al Clin Orthop 1981

- 32/39 G/E results




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



- 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




Open Physis




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




Hauser distalisation

- for patella alta

- operation in isolation had disappointing results

- get posteriorisation tubercle and increased forces across PFJ



- anteromedial transfer

- osteotomy lateral to medial

- direct osteotomy anteriorly

- unloads PJF


Fulkerson Osteotomy APFulkerson Osteotomy LateralFulkerson Osteotomy Skyline



- 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




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





- skeletally immature with malalignment



- 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




Fondren et al JBJS Am 1985

- 43/47 G/E results


Medial Operations


1.  MPFL reconstruction



- patient with history initial traumatic dislocation

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




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




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




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



- MPFL needs to be intact or won't work

- laxity / stretched / attenuated structures




Insall procedure

- medial flap sutured 1 cm over lateral flap




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





- trochlea dysplasia

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




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




Nelitz et al AJSM 2013

- trochleoplasty + MPFL in 26 knees

- no redislocation, no complications

- 96% statisfied


Tibial Derotation Osteotomy



- excessive external tibial torsion > 45 degrees

- 1 / 5000 people


Tibial Derotation Osteotomy


Tibial Derotation OsteotomyTibial Derotation Osteotomy Lateral




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



Usually occurs in young people

- often previous history of tendonitis ± steroid injections




Usually at level of inferior pole of patella

- less common at tibial tubercle

- mid-substance ruptures rare




Severe pain

Palpable defect

Extensor deficit / unable to SLR




Patella alta / high riding patella


Patella Tendon Rupture


Distal Pole Patella Fracture


Patella Tendon Bony Avulsion




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


Patella Tendon Rupture MRIPatella Tendon Rupture MRI


Patella Tendon Tear MRI


Acute Management


Requires operative repair





- 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


1.  Tendon torn off patella


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


2. Avulsion from tibial tuberosity


Repair with suture anchors


3.  Midtendon rupture


May need augmentation with hamstring tendon




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




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



Patellar Tendinitis




Most common in athletes

- especially if involved in running, jumping and kicking

- over use injury


Basketball players




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




Usually normal


May see

- traction spurs

- calcification of patella tendon


Patella Tendon CalcificationPatella Spur




Cyst / Degeneration


Jumpers Knee MRI


Traction spurs / calcification / ossicles


Patella Tendonitis Calcification MRIPatella Tendon Calcification MRIPatella Spur MRI




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






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




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






Fails to resolve & interferes with activity






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




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



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




Often preceded by quadriceps tendinosis


Quadriceps Tendinosis MRIQuadriceps Tendinosis 2




1.  Avulsion of quadriceps tendon from superior patella

2.  Rupture of belly of rectus femoris

3.  Rupture at musclulotendinous junction in athletes




Quadriceps Tendon RuptureQuads Tear


Palpable gap in tendon



Extensor lag

- function usually good if tear incomplete


Extensor Lag


Diagnosis can be missed once acute features settle




Patella Baja


Quadriceps Rupture




MRI Chronic Quadriceps RuptureQuads rupture MRI







- immobilise for 4/52 in extension

- then rehabilitate


Rectus Femoris Avulsion 1Rectus Femoris Tear 2



- surgical repair



- surgical repair


Surgical Technique



- 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



- 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



- flat portion oversewn proximally

- two limbs passed through drill holes in patella

- sewn onto themselves



Sinding - Larson - Johanssen



Active pre teen boy

- activity related pain

- common in high jumpers




Fragmentation / calcification of inferior pole

- repetitive traction injury where PT inserts

- tender at this point




I     Normal

II    Ca inferior pole irregularity

III   Coalesce Ca inferior pole

IV    Incorporation of Ca




Patella stress fracture

Sleeve fracture

Type 1 bipartite patella

Jumper's knee in older patient




Self- limiting 

- symptomatic treatment

- can use cast immobilisation


Rarely surgical excision




Postero-Lateral Corner Injury

Acute PLC Background



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



- 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



- 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



- 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



- inserts anterior aspect of popliteal sulcus

- femoral insertion always anterior to LCL

- average 18 mm from LCL insertion on femur



- 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





- 1° lateral stabiliser at 30° flexion


2° lateral stabilisers 




- popliteus

- biceps femoris



- popliteal-fibular ligament

- arcuate Ligament



Tertiary medial stabiliser





5% of knee injuries have a component of PLC instability




Twisting injury 


Direct blow to anteromedial side of knee

- often hyperextension injury


Associated Injuries




CPN (10%)




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




Gait / Stance


Varus thrust in gait and single leg stance

- due to ER of tibia 

- apparent varus

- flexed attitude to knee




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




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




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




Anteromedial bone bruise


1.  LCL




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




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




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



Early repair < 3/52 better than late repair




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









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





- 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



- only 2 of 17 had 1+ laxity



- doesn't deal with LCL / Popliteus femoral avulsion




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%)



- 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



- very heterogenous groups



Chronic PLC Management



1.  Limb alignment


2.  Ligament reconstruction





- confirm grade 3 laxity in extension


Dial test

- confirm PLC instability

- > 10o compared with other side


Increased Dial Test 30 degrees






Stress radiographs useful

- Telos

- confirm PCL / LCL


Long leg views

- assess for varus malalignment




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




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




ACL / Posterolateral corner / patient in varus




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



- 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



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




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



- 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



- 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




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



- 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



- inserts anterior aspect of popliteal sulcus

- 18.5 mm anterior and down from LCL



- 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



- 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




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




Supine with sandbag under buttock

- knee flexed 90°

- radiolucent table

- II available





- Gerdy's tubercle and midpoint femoral condyles



- 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



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 





- 3 mm proximal and 5 mm posterior to the epicondyle



- 6 cm distal to the joint line


Xray landmarks


Wijdicks et al JBJS Am 2009

- describes radiographic landmarks

- aids reconstruction






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



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




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




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



- 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



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


Overcome by ER femur 3°


2.  Anatomic alignment



- 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



1.  Bony resection first

2.  Ligament balancing 



- 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



- cut tibia perpendicular to mechanical alignment

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



- again matched mal-alignments 

- usually gives good result if not severe deformity / contracture



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



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



- loosening  30%

- infection   20%

- PFJ           14%

- pain          9%

- instability  5%



- 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



- 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



- 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



- femur + tibia    48%

- tibia only          8%

- femur only        4%

- insert only        13%

- patella only       10%

- patella + insert  7%   




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%





Coronal Plane Balancing / Varus Valgus


Whiteside's Manual


  Medial Structures Lateral Structures
Tight in Extension

Posterior MCL


Posterior capsule

Pes Anserinus


Posterior capsule

Lateral Head GN



Tight in Flexion

Anterior MCL




PL corner




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



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

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



- 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



- symmetric gap

- did not cut enough tibia



- cut more proximal tibia


2.  Loose in extension and flexion



- symmetric gap

- cut too much tibia



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



- insufficient posterior femoral cut

- PCL scarred and too tight

- no posterior slope in tibial cut



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



- asymmetric gap

- cut too much posterior femur



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



- insufficient distal femoral cut

- tight posterior capsule



1.  Release posterior capsule / osteophytes

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


6.  Loose in extension



- asymmetric gap

- cut too much distal femur or

- AP size too big



1.  Distal femoral augments

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








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 only 10-15% below trifurcation


Bilateral DVT in 10-15%




Mechanical prophylaxis


- 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




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




Intraoperative Fractures


1.  Shaft fracture from IM rod


TKR Femoral Shaft Fracture IM Rod


2.  Posterior condylar fracture



- assess stability

- ORIF if needed


TKR Intraoperative condylar fractureTKR Condylar Fracture Lateral


Periprosthetic Fractures




Within 15 cm of the joint line

Within 5cm of the implant





- 0.6% primary TKR

- 1.6% revision TKR


Most common > 70 / female / revision TKR




Low velocity fall in elderly osteoporotic patient


Associated Factors



- RA

- steroids

- osteopenia



- revisions

- ? notching

- arthrofibrosis / MUA

- wear / osteolysis






1. Posterior referencing and down sizing femur

2.  Internal rotation femur / medial notching




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



- proximal to femoral prosthesis

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




Prosthesis stability


Bone stock


Suitability of femoral implant for IMN


Non-Operative Management




For minimally displaced fractures




High rates of nonunion / malunion / stiffness

- Better outcomes with operation unless significant co-morbidities


Operative Management




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




Minimally invasive technique

- may need unicortical screws distally




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




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




May be biomechanically superior

Have to open TKR to perform operation

- risk deep infection




Technically feasible

- CR knees contra-indicated

- must have sufficient sized hole in PS femoral component

- consult company as to suitablity

- small diameter nail




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



- sufficient bone above implant for distal locking



- stress riser between femoral implant and nail

- must ensure correct alignment


TKR Femoral FractureTKR Femoral Nail APTKR Femoral Nail Lateral


4.  Revision TKR



- very distal fracture

- insufficient bone stock

- loose prosthesis



- 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







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




70% gram positive cocci

- 2/3 Staph epidermidis

- 1/3 Staph aureus


15% Gram negative





Wound problems






- 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



- off Antibiotics




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



A Fit

B Medically compromised

C Unfit for anaesthetic



- type

- sensitivities



- stable

- loose



1.  Washout / debridement

2.  Two stage revision

3.  One stage revision

4.  Antibiotic suppression

5.  Arthrodesis

6.  Amputation


1. Debridement



- early post operative infection < 3/52

- acute haematogenous < 3/52 

- sensitive organism

- stable prosthesis

- healthy host 




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




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




Bradbury et al J Arthroplasty 2009

- acute infection with MRSA

- failure rate of 84%


2. Two Stage Revision



- 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



- 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



- 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



- 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




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




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




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



- less debilitating to patient

- less expensive management



- increased risk of failure



- healthy host

- known sensitive organism



- remove implant / cement

- debride as above

- change all operating equipment / rescrub

- new implants with antibiotic laden cement

- post operative Antibiotics




Sofer et al Orthopade 2005

- successful in 14 / 15 knees

- careful patient selection / experienced surgeon


4.  Antibiotic Suppression




1.  Prosthesis removal not feasible 

- patient medically unwell


2. Organism

- susceptibility to oral antibiotic

- minimal toxicity from antibiotic


3.  Prosthesis not loose




Long term success very unlikely





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




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



- 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



- gentle tissue handling

- minimise surgical time

- use of antibiotic loaded cement / Tobramycin




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

Skin dressings left intact 4 days

If IDC needed then give prophylactic AB






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



- can get knee dislocation / post jump



- 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




A. Iatrogenic collateral ligament injury



- advance / imbricate / augment / reconstruct collateral

- full revision to VVC / CCK constrained implant


B.  Failure to balance knee 



- under release deformity in the concavity



- increase poly thickness, further releases in concavity


TKR Varus Coronal Instability TKR Varus Instability Increase Poly Thickness


C.  Insufficient poly / loosening over time



- equal varus and valgus instability



- 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



- increase poly thickness


TKR Poly WearTKR Poly Wear Lateral


2.  Loosening / collateral ligament damage



- 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




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




Knee painful


Signs infection



- able to aspirate


Careful examination of spine / hip / vascular status





- may be normal in face of pathology

- can't DDx infection vs loosening on XR

- serial comparison very important


Bone Scan



- 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



- pathology unlikely if negative



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


Bone Scan Infected TKR



- 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



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





Little value

- increased in 15%

- raised only if very septic




> 30 mm 

- 80% sensitivity & specific 



- raised post operatively for up to 12 months

- remote pathology can elevate

- permanently raised in RA

- can be raised in aseptic loosening




> 10 mg/l

- 90% sensitive & specific

- negative predictive value 99%



- more predictable response post OT

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

- rarely increased with loosening





- 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%





Instability / Maltracking


Loosening or failure of component

Patella Clunk Syndrome

Extensor Mechanism Rupture




PFJ complications 5%


PFJ Instability / Maltracking




Catastrophic wear

Component loosening






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





- Assess tracking


- skyline views

- lateral tilt / subluxation


TKR Good Patella TrackingTKR Patella Maltracking



- rotational profile of the components





- 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



- medialise patella component

- revise malrotated components


Patella Fracture


TKR Patella Fracture





- 0.1% Primary

- 0.6% Revision




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







- extensor mechanism intact

- patella component stable


TKR Patella Fracture Undisplaced



- immobilse for 6 weeks then progressive ROM





- loose component or ruptured extensor mechanism



A.  Patella ORIF if component stable

B.  Removal component if unstable + Patella ORIF


Patella Component Loosening




Cemented patella

- < 2%


Uncemented higher

- 0.6% - 11.1%




Metal backed designs


Fracture / AVN of patella

Excessive bone removal




A.  Remove and leave


B.  Revision

- need > 10 mm bone left


C.  Patellectomy


Patella Clunk Syndrome




Clunk with knee extension

- as patella exits groove at 30-45° extension


Complain of symptoms when rising from chair or climbing stairs




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




Increased incidence in PS knees


Newer designs

- deeper patella groove

- more posterior femoral box




Can visualise nodule on ultrasound




Arthroscopic debridement


Dajani et al J Arthroplasty 2010

- good result in 15 knees


Rupture of Extensor Mechanism








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




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












70 swing phase

80o climb up stairs

90o climb down stairs + sit down in chair

100o low chair




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°




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




Continuous epidural infusion best, but prohibits anticoagulation


Combination of

- regular paracetamol

- femoral nerve catheter

- PCA / slow release opiates (oxycontin)



- risk of renal impairment in elderly

- even COX 2


2.  Infection


Always consider with loss of ROM


3. Surgical Technique



- 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 



Non resurfacing and pain

Joint line elevation - patella baja


4.  Poor Patient Motivation


5.  Arthrofibrosis




A.  Exclude infection


B.  Aggressive physiotherapy and adequate analgesia





- ROM < 90o at 6/52

- doesn't work for FFD

- FFD will usually resolve with time



- epidural catheter

- aspirate for infection

- manipulate

- post operative epidural and CPM



- 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



- 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








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



- acute ischaemia post operatively

- traumatic aneurysm

- AV fistula



- 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



- 25-50% amputation rate

- deep infection and sepsis

- wound healing issues





- symptoms arterial insufficiency

- rest pain, intermittent claudication

- bypass surgery to heart or leg

- diabetic patients




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%



- 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




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)



- 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



- 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


Fracture Malunion

Previous Osteotomy




1.  Intra-articular correction

2.  Simultaneous osteotomy and TKR

3.  Staged correction and TKR


1.  Intra-articular correction 





- 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



- line drawn medullary canal of distal segment

- must pass between condyles

- maximum 30˚ varus


TKR Preop Tibial Deformity


2.  Osteotomy and TKR



- bone preserving

- less bone resection to achieve correction

- augments not required



- 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





- severe varus deformity

- would need > 1 cm of medial augments



- medial opening wedge osteotomy

- preserves bone




Attempt to reduce outliers in all 3 planes of the knee

- improve alignment

- theoretically improve survival and outcomes


TKR Valgus Femoral Implant Non Navigated




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




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




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




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




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




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




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


- 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




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


°Extensor mechanism



Relative Contra-indications


Previous osteomyelitis


Young patient


10% 7 year revision rate < 55 in AJR


Poor medical condition




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



- 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




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




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




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




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 



- 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




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



- 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




A.  Intra-medullary best

B.  Extramedullary less accurate 

C.  Significant deformity of femur / THR

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




Entry point


Clear osteophytes from intercondylar notch



- 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



- 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



- 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



- avoid notching

- avoid overstuffing PFJ



- loose flexion gap from downsizing


B.  Posterior referencing

- posterior condyles up

- if between sizes upsize to avoid notching



- stable flexion gaps



- 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



- 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



- resect more lateral condyle than medial



- 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




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



- 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



1.  Lowers joint line

2.  Poorer strength cancellous bone

3.  Decreased surface area

4.  Removes PCL / requires PS


Severe varus deformity



- 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



- stay subchondral on lateral side

- never more than 10 mm cut lateral side

- build up medial side




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




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




Wash all surfaces

- H202

- dry with sponges

- good exposure of tibia


All components opened / checked / ready




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



- 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




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




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




Water tight to prevent haematoma drainage

- 4-5 1 vicryl figure 8 sutures

- 1 vicryl locking suture


Post operatively


IV ABx x 4




Low dose LMWH that night or next day for 4 weeks


Early mobilisation



1.  Intra-articular analgesia

- combinations LA / NSAIDS

2.  Epidural

3.  Femoral nerve blocks / sciatic nerve blocks

4.  PCA


6.  Long acting oxycontin early

- aids wean off PCA




Immediate weight bearing and ROM

- quadriceps exercises

- can use splint until SLR

- need adequate analgesia





- improves clearance of blood from joint

- reduces need for analgesia

- increases early ROM



- no evidence improves outcome

- interferes with wound healing



TKR Design




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



- low conformity

- round on flat designs (PCL retaining)

- increased ROM but high contact stresses in the poly

- sliding and skidding 

- delamination and particle production



- 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




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




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)




1.  Bearing Dislocation

- soft tissue and ligamentous balancing crucial

- severe deformity is a contra-indication


2. Anterior soft tissue impingement with AP translation




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




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





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




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



- cheaper (by $2000)

- good in elderly patients

- eliminates backside wear



- lack of modularity

- difficult to insert if PS


Metal backed



- improved load distribution

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

- modularity enables increasing trialling before definitive implants



- problems with locking mechanism

- most have some micromotion

- potential for backside wear / increased particulate debris


TKR Dislocated Fixed Bearing Poly




Best technique controversial




1. Cemented

2. Press-fit with porous ingrowth

3. Hybrid




Current standard

- longest follow up

- cement "Seal" to particle migration

- easier to revise if infected




Initial results comparable



- very difficult to remove well fixed uncemented infected TKR



- faster operation




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%




Cobalt chronium femur

- can be covered with oxidised layer

- S&N oxinium


Cobalt chronium tibial base plate

- can be porous and HA coated




Anatomic differences


Female Femur

1.  Narrower medial lateral width for same AP diameter

2.  Variety of subtle PFJ anatomical and biomechanical differences



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

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









Need the least amount of constraint necessary to obtain sufficient stability


Increasing constraint



- increase stability



- 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 



- 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




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




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




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)




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






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




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




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



- severe valgus deformity

- collateral ligament deficiency

- bone defects

- irreconcilable flexion-extension imbalance after PS implant



- increased bone loss

- potentially higher rate of aseptic loosening

- fracture of the tibial stem

- recurrent instability




Total Condylar III / TCIII (Depuy)

CCK / Condylar constraint knee

Legion (S&N)




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




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



- increased bone resection

- increased risk of aseptic loosening

- unusual breakages / dislocations / failures



- severe collateral instability

- severe bone loss




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



1. Always resurface

2. Never resurface

3. Selectively resurface


Decision Making



- literature divided on issue



- 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



- reduced anterior knee pain

- improved stair climbing

- reduced revision rate



- 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



- inflammatory arthritis

- mal-tracking

- PF OA as main indication for TKR


Patella OA SubluxationPatella Tilt OA



- 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




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



- standard technique

- cut patella

- cement all poly patella


TKR Patella Onlay



- 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



- overstuffs PFJ / anterior knee pain

- increases joint reaction force

- decreased flexion



- 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



- limits flexion

- due to patella impingement on tibia in flexion




- tibial tuberosity transfer

- tibial fracture




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



Loss of material from solid surface due to mechanical action


Types of wear



- more complex movements compared with THR

- rolling, sliding and rotation

- delamination, pitting and fatigue failure of the poly surface



- adhesive wear (most common in TKR)

- abrasive wear

- third body wear

- fatigue wear - delaminating

- wndersurface wear


Patient factors





Inflammatory arthritis




Site of wear



- articular side wear

- conformity

- PS v CR

- mobile v fixed bearing



- undersurface wear

- between baseplate and poly




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




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




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




A valgus knee has a tibiofemoral angle of > 10o





- RA


TKR Bilateral Valgus OA



- rickets, renal



- tibial malunion

- plateau fracture



- physeal arrest




Primary OA

- most common

- females

- unresolved physiological valgus deformity




Soft tissue abnormalities


A.  Contraction of lateral structures



- 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



A.  Easy to evert patella because

- increased Q angle

- tibial tuberosity lateralised



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



A.  Direct access to lateral structures

- makes these easier to release

B.  Preserves blood supply to patella



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



- 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




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





- more common if valgus > 12o



Revision TKR


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




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




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




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




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


IndicationsRevision TKR


Aseptic loosening



Wear & breakage components







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




Lower limb

- old incisions

- pulses

- sensation (Charcot neuropathy)



- need 110o flexion to remove and insert components

- otherwise will need tibial tubercle osteotomy



- 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



- secondary to osteolysis 

- iatrogenic when removing components




Tibial bone loss

- often medial, due to implant in varus


Femoral bone loss

- often posterior femoral condyles




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




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









1.  Reduce implant loosening

- offset load sharing to diaphysis

- 30% if > 70 mm


2. Restore optimal alignment




1.  Using augments or bone grafting


2.  Increased constraint 

- VVS / hinge







Press fit uncemented



- 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



- easy to use

- suit IM system of alignment in revisions



- 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





- increased area of fixation



- 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




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



- 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)




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



- 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



- 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



- 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




Trans-epicondylar axis most reliable

- posterior femoral condyles may be more deficient laterally than medially

- set correct rotation

- freshen AP and chamfer cuts




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




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




1.  Femoral component malrotation


2.  ITB deficient


- brace for 3/12


3.  LCL deficient

- VVC + reconstruction

- semitendinosus / lars / allograft

- find centre of rotation on femur

- pass through drill hole in fibula






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


3.  Immobilise in extension for 6 weeks


Revision TKR Staple Patella Tendon Insertion

Unicompartmental Knee Replacement


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




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




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




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




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





- 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




One finger test

- patient points to affected compartment only




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






UKA Oxford APUKA Oxford Lateral



- 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




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



- 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






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



- 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



- 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



- 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



- worse if need augments / stems


UKA Revision to Long Stem TKRUKA Revision To TKR Lateral




Oxford Technique

PreoperativeUKA Oxford AP



- 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



- 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



- 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