EpistemisInstability of the patellofemoral joint
Specialty: Musculoskeletal.
Why it occurs
- Femoral trochlea dysplasia (shallow trochlear groove)
- Patella alta (excessively long patellar tendon)
- Insufficiency or rupture of the medial patellofemoral ligament (primary passive stabilizer)
- Severe genu valgus or increased tibial external rotation
- Atrophy or weakness of the vastus medialis oblique muscle of the quadriceps
- Generalized ligamentous laxity (hypermobility syndrome)
Initial workup
AP knee radiography, lateral in flexion at 30° and axial projections of the patella (at 30°, 45° and 60°) | Magnetic resonance imaging of the knee (method of choice to assess rupture of the medial patellofemoral ligament, bone contusions in the lateral femoral condyle and integrity of the patellar cartilage).
red flags
Episode of patella dislocation that remains laterally locked, with exquisite pain, immediate blood swelling (hemarthrosis) and inability to extend the leg (orthopedic emergency for closed reduction under analgesia).
Standard management
- Dexketoprofen — 25 mg every 8 hours orally, adjuvant in initial temporary immobilization with patellar centering orthosis
- Chondroitin sulfate — 800 mg daily orally as a chondroprotective against repetitive cartilage damage due to subluxation
- Topical application of 0.5% piroxicam gel on the anterior aspect of the knee.
Educational guidance for study. It is NOT a prescription recommendation. The actual choice depends on the cause, the patient, and current guidelines.
- Area
- Musculoskeletal
- Listed causes
- 6
- Treatment options
- 3