Indications
Recurrent disabling patella instability
Options
MPFL reconstruction
Tibial tuberosity osteotomy
Trochleoplasty
Derotation osteotomy
Results
MPFL v MPFL + TTO
- systematic review of isolated MPFL v MPFL + TTO
- 31 studies and 1400 patients
- isolated MPFL: mean Kujala 85, redislocation 3%
- MPFL + TTO: mean Kujala score 84, redislocation 3%
TTTG > 20
- systematic review of isolated MPFL v MPFL + TTO with TTG > 20
- 13 studies and 400 knees
- no difference in redislocation rates or complications
- improved Kujala scores with isolated MPFL
MPFL reconstruction
Indication
Mild patella instability
TTTG < 20
Options
MPFL reconstruction
- autograft / allograft
- fixation techniques
- single bundle / Y graft
Medial quadriceps tendon femoral ligament (MQTFL)
Technique
Patella
- expose medial patella
- identify superior half of patella
- fixate graft with screws / bone anchors
- identify layer between medial retinaculum and capsule
- pass graft superficial to capsule
Schottle's Point
- radiographic landmark for isometric insertion point MPFL on femur
- 1 mm anterior posterior cortex
- 2 mm distal to MFC origin
- proximal to Blumensaat's line
Femur
- dissection down to bone
- protect saphenous nerve
- use xray to find Schottle's point
- aim femoral pin anterior to Blumensaat's line / 30o
- drill for size of graft
- pass graft and fixate with screw
Results
- systematic review of isolated MPFL for recurrent patella instability
- mean postoperative Kujala score 86
- 84% return to sports
- recurrent instability 1%
- positive apprehension sign 4%
- reoperation rate of 3%
Complications
Anterior femoral tunnel
Infection
Patella fracture
Tibial Tuberosity Osteotomy
Indication
TTTG > 20
Severe lateral patella subluxation
Technique
Incision midline over tibial tuberosity
- expose tibial tuberosity medial and laterally
- identify and protect patella tendon insertion
- insert K wires to guide osteotomy
- some obliquity to allow antero-medialisation
- osteotomy 1 cm deep, 6 cm long
- consider resection 1 cm to distalise / correct patella alta
- fix with 2 or 3 bicortical 4.5 mm fully threaded screws with lag screw technique
- +/- distal plate over osteotomy to minimize stress fracture risk
Patella femoral chondral defects
Consider cartilage regeneration procedure
- microfracture / MACI / de novo / AMIC
www.boneschool.com/knee-cartilage-defects
MPFL reconstruction
Complications
Berk et al Orthop J Sports Med 2023
- review of 344 TTO
- stiffness 16%
- superficial infection 8%
- hemarthrosis 6%
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
Femoral derotation osteotomy
- 144 patients treated with MPFL + TTO
- poorer outcome scores with femoral anteversion > 30 degrees
- systematic review of FDRO + MPFL
- better outcome scores with combined surgery in setting of increased femoral anteversion
- no nonunion
Tibial Derotation Osteotomy
Indication
- excessive external tibial torsion > 45 degrees
- 1 / 5000 people
Results
Drexler et al KSSTA 2013
- good outcome for 15/17 knees
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