Peggers Super Summaries: PFJ

Transcription

1 Patellofemoral Joint: ANATOMY: Largest sesamoid ossifying at 3-5 years of age Multiple foci having a sec ossification centre SUPEROLATERAL Helps increase moment arm PATELLOFEMORAL OA Incidence 10% of knee OA 4:1 female predominance Aetiology o Malalignment Q angle o Trauma o Ligamentous laxity o instability History o Insidious onset o Variable pain stair climbing as increase BW and patella engagement on flexing o Quads inhibition and pseudo giving way o Clicking noise Examination o Static Q angle from ASIS to patella then patella to tibial tuberosity <20 degrees N Squinting patella femoral anteversion Leg length o Dynamic Localising pain on squatting o Couch Quads VMO and tenderness Tracking J Sign Apprehension Imaging o Sulcus angle 138 degrees o Insalls ratio o Patello-femoral index Medial distance / lateral distance on skyline Patellofemoral instability: PATHOPHYSIOLOGY Soft tissue causes o Hypoplastic VMO

2 o Extensor muscle dysplasia Bony causes o Trochlear dysplasia o Patella alta o Rotational deformities o Patella dysplasia RECURRENCE 17 % 1 st time & 50% second time Risk factors: o Initial age of presentation o Pre existing anatomy o Previous episode IMAGING: Plain o OCD o Insall s Skyline o Patella tilt > 20 0 o TT-TG distance >20mm o Dysplasia Dufour A shallow C lateral tilt D medial boss MRI o For haemoarthrosis or OCD o Assc ligamentous injuries ACUTE DISLOCATION FEATURES: Haemoarthrosis Bruising over medial knee Adductor tubercle pain (Bassett s sign) just posterior to MPFL attachment Apprehension positive EXAMINATION

3 Standing o Q angle 14 degrees males +/ degrees females +/- 3 o Squinting patella o Beighton score Dynamic o 1 leg squat Supine o Haemoarthrosis get MRI o VMO wasting o J sign o ROM o Lateral apprehension o Side to side glide moves grossly laterally torn Medial patellofemoral ligament o Patella tilt if unable to raise lateral side tight lateral retinaculum Prone o Tibial torsion measure angle of foot with femur whilst knee flexed to 90 0 MANAGEMENT Non surgical o Crutches do not splint straight leg causes dislocations (risk ) o PT see at 4 months Surgical o Soft tissues Medial retinaculum reefing Medial patella femoral reconstruction must be isometric and use 3rapezie o Bony Tibial tubercle transfer when TT-TG is >20mm Trochleoplasty for congenital non congruent cases Tibial and femoral osteotomy Patellofemoral joint from INSTALL S BOOK RADIGRAPHIC EVALUATION AP o Size and shape o Small or 3rapeziecto o Bi-partite superolateral Lateral

4 o Insalls height o Dejour crossover sign Axial o Lateral facet larger facet o Joint space narrowing o Trochlear o Traction spur = tight retinaculum PATELLOFEMROAL CONGRUENCE SKYLINE VIEWS Congruence angle o lines to lowest and highest points o Usually -6 o +/- 6 o Sulcus angle o Condylar angle 138 o +/- 6 o Lateral patellofemoral angle o Between condyles and fact should open slightly o If parallel = tilted Patellofemoral index o N = <1.6 medial side slightly wider than lateral side MALALIGNMENT PATTERNS Mx (surgery involve either soft tissue work or bony work) Tilt Stretching of lateral retinaculum Quads strengthening Patella taping Lateral release Tibial tuberosity osteotomy if TTTGD > 20mm Subluxation Bracing Taping VMO Orthotics Medial reefing Tibial tuberosity transfer Both Bracing

5 Taping VMO orthotics Lateral release Tibial tuberosity osteotomy if TTTGD > 20mm Dislocation VMO Taping Bracing For OCD Loose bodies Chondroplasty Tibial tuberosity transfer Permanent dislocation Extensor mechanism becomes shortened = need v-y plasty Dysplastic patella Soft tissue surgery will unlikely be successful if used alone FACTORS INVOLVED WITH INSTABILITY Bony o Intersection sign (Dejour) Type 1 intersection at bottom of trochlear Type 2 cross over sign Type 3 trochlear are parallel and anterior bump o Trochlear boss Ie femoral shaft is anterior to trochlear o Patella height >1.2 install s o TTTG >20mm o Valgus knee Intermalleolar distance > 9cm o Femoral anteversion >15 o o Recurvatum >5 o Soft tissues

6 o Weak VMO o Tight retinaculum causes tile o Torn Medial patellofemoral ligament