Management

Non-operativePatella Instability MPFL and TTT AP

 

Results

 

90% respond 

- very important

- 6 - 12 months minimum before offering surgery

 

Physiotherapy

 

1.  Stretches

- quads stretches

- ITB

- lateral retinaculum

 

2.  Quads strengthening

- avoid pain

- PFJ contact pressures lowest from 0-30o

- short arc quads extension

- closed chain VMO exercises

 

3.  Taping / bracing

- patella cut out brace

- little hard evidence

- may provide proprioceptive feedback

 

Operative

 

Indications

 

For failure of non-operative treatment 

- patella tilt with lateral patella pain

- recurrent instability

 

Options

 

Depends on pathology

- assessment and investigation critical for deciding treatment

 

1.  Isolated Patella tilt

 

Indications

- clinical and xray patella tilt

- no instability / malalignment

- excessive lateral pressure syndrome

 

Techniques

 

1.  Arthroscopic lateral release

- knee in extension

- camera in AM portal

- hook diathermy in AL portal

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

- release retinaculum under vision

- must ensure SLGA coagulated / can visualise

- let down tourniquet at end of procedure

- ensure can evert patella 90o at end

 

2.  Smiley knife release

- arthroscopy

- insert in AL portal

- divide retinaculum by feel

 

Post op

- drain 24 hours

- protect for 1 week

 

Results

 

McGinty et al Clin Orthop 1981

- 32/39 G/E results

 

Complications

 

A.  Haemarthrosis

- can be major / problematic

- insert drain, splint and minimise activities first few weeks

- manage via early washout / insertion drain

 

B. Medial subluxation

- extending release too far into VL

- performing lateral release when have ligamentous laxity and instability

 

Patella subluxation / recurrent dislocation

 

Issues

- must have had long non operative period

- treatment depends on cause

- different treatment options in skeletally immature

 

Treatment algorithm

 

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

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

- MPFL reconstruction / VMO advancement / medial reefing

 

2.  Recurrent subluxation + malalignment (TTTG > 20)

- above + add TTT (tibial tuberosity transfer)

- Roux-Goldthwaite instead of TTT if physis open

 

3.  Above + Excessive femoral anteversion

- consider DRFO (derotation femoral osteotomy)

 

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

- consider tibial derotation osteotomy

 

5.  Trochlea dysplasia

- trochleoplasty

 

5.  Patella alta

- distalise TT

 

Surgical Algorithm

 

1.  Perform lateral release

- rarely needed

- most patients are ligamentous lax / hypermobile patella

- may be needed in chronic setting or if congenital

 

2.  Perform TTT (if TTTG > 20)

- incision over TTT

- medialise at least 1 cm

- ensure some element of Fulkerson / anteriorise

- can distalise if patella alta

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

- reassess stability

 

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

- acts as checkrein to lateral displacement

- usually harvest hamstring autograft

- medial incision

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

- reassess for stability

 

4.  Lateral Trochlea Elevation

- still unstable after above operations

- small lateral incision

- beware fracturing lateral femoral condyle

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

 

 

 

Skeletally Immature

 

Roux-Goldthwaite

 

Indications

- skeletally immature with malalignment

 

Technique

- lateral half PT rerouted

- under medial PT

- stitched to MCL / sartorius

 

Technique Modification

 

Take medial half patella tendon

- suture to MCL

 

PT transfer + MPFL

- incision midway between PT and MCL

- identify patella tendon

- divide in two

- sharp dissection of medial half off bone

- dissect medially

- divide fascia and retinaculum to expose MCL

- suture to MCL with 2.0 non absorbable sutures

- through same incision can harvest hamstrings for MPFL reconstruction

 

Results

 

Fondren et al JBJS Am 1985

- 43/47 G/E results

 

Medial Operations

 

 

 

2.  Medial imbrication

 

Indications

- MPFL needs to be intact or won't work

- laxity / stretched / attenuated structures

 

Technique

 

Insall procedure

- medial flap sutured 1 cm over lateral flap

 

Results

 

Scuderi et al JBJS Am 1988

- combined with lateral release

- normal and abnormal Q angle

- 42/52 G/E 81%

 

Barber et al Arthroscopy 2008

- TTT + medical plication in 34 knees

- 91.4% stability

 

Zhao AJSM 2012

- RCT MPFL v medial plicaiton

- 100 patients

- recurrent instability 7% v 16%

- better Kujala scores in MPFL

 

3.  VMO advancement

 

Madigan procedure

- VMO detached and advanced laterally and distally

- sutured to fascia on patella

 

Trochleoplasty

 

Indication

- trochlea dysplasia

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

 

Techniques

 

1. Dejour Trochleoplasty

- lift up anterior aspect femoral condyles

- deepening of trochlea

- replacement of LFC

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

 

Utting et al JBJS Br 2008

- 50/54 92% 

- combined with other procedures as required

 

2.  Elevate lateral edge of lateral femoral condyle

- insert osteotome

- gently elevate without fracturing chondral surface

- insert 2 - 3 mm of iliac crest bone graft

- no need for stabilisation

 

Results

 

Nelitz et al AJSM 2013

- trochleoplasty + MPFL in 26 knees

- no redislocation, no complications

- 96% statisfied

 

Tibial Derotation Osteotomy

 

Indication

- excessive external tibial torsion > 45 degrees

- 1 / 5000 people

 

Tibial Derotation Osteotomy

 

Tibial Derotation OsteotomyTibial Derotation Osteotomy Lateral

 

Results

 

Drexler et al KSSTA 2013

- good outcome for 15/17 knees

 

Chronic Dislocation

 

Chronic Patella Dislocation 1Chronic Patella Dislocation 2Chronic Patella Dislocation

 

Chronic / congenital

- patella subluxed out of joint

- patella alta

- treat with identical principles

- lateral release / TTT / MPFL reconstruction

 

Chronic Patella DislocationChronic Patella DislocationChronic Patella Dislocation 5