Mechanism
- softening, erosion and fragmentation of articular cartilage, predominantly medial aspect of patella
- commonly seen in active young females
- predisposing factors
- malalignment causing patellar maltracking (patellofemoral syndrome)
- post-trauma
- deformity of patella or femoral groove
- recurrent patellar dislocation, ligamentous laxity
- excessive knee strain (athletes)
Clinical Features
- deep, aching anterior knee pain
- exacerbated by prolonged sitting (theatre sign), strenuous athletic activities, stair climbing, squatting
- sensation of instability, pseudolocking
- tenderness to palpation of underside of medially displaced patella
- pain with extension against resistance through terminal 30-40 degrees
- swelling rare, minimal if present
Investigations
- x-rays: AP, lateral, skyline
Treatment
- non-operative
- continue non-impact activities, NSAIDs, PT (quadriceps strengthening)
- surgical with refractory patients
- tibial tubercle elevation, arthroscopic shaving/debridment, lateral release of retinaculum
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PEARL
pain with firm compression of patella into medial femoral groove is pathognomonic of chondromalacia patellae |