Review Question - QID 216884

The medial patellofemoral ligament (MPFL) is located on the medial femoral condyle, distal to adductor tubercle and proximal to MCL attachment. It is torn in cases of lateral patellar instability.

Patellar instability is a condition characterized by patellar subluxation or dislocation episodes as a result of injury, ligamentous laxity or increased Q angle of the knee. Diagnosis is made clinically in the acute setting with a patellar dislocation with a traumatic knee effusion and in chronic settings with passive patellar translation and a positive J sign. Treatment is usually nonoperative with bracing for first time dislocation without bony avulsion or presence of articular loose bodies. Operative management is indicated for chronic and recurrent patellar instability.

Iobst et al. reviewed knee injuries in skeletally immature athletes. They reported that hemarthrosis is associated with peripheral meniscal tears, anterior cruciate ligament ruptures, tibial tubercle avulsion injuries, and patellar/femoral osteochondral fractures. They concluded that the primary diagnostic tool for patients with a knee injury is a clinical examination by a physician well trained in knee evaluation.

Fithian et al. prospectively reviewed the epidemiology of acute patellar dislocation, the risk of subsequent patellar instability episodes, and the risk factors for subsequent instability episodes. They reported that patellar dislocators who present with a history of patellofemoral instability are more likely to be female, older, and have greater risk of subsequent patellar instability episodes than first-time patellar dislocators. They concluded that risk of recurrent patellar instability episodes in either knee is much higher in this group than in first-time dislocators.

Schepsis et al. reviewed lateral instability of the patella. They reported on the anatomy, biomechanics, indications, and technique for surgical reconstruction of the MPFL. They concluded that the MPFL has been demonstrated to be the major soft tissue stabilizer to prevent abnormal lateral displacement of the patella.

Figure A is an axial MRI image of the knee demonstrating a torn MPFL. Illustration A depicts the structures that attach to the distal medial femur

Incorrect Answers:
Answer 1: The adductor magnus attaches to the adductor tubercle
Answers 3 & 4: The medial patellofemoral ligament (MPFL) is located on the medial femoral condyle, distal to adductor tubercle and proximal to MCL attachment.
Answer 5: The PCL originates of the lateral wall of the medial femoral condyle