Patellofemoral Joint

articulatio patellofemorale

The patellofemoral joint is the articulation between the posterior patella and the trochlear groove of the femur, transmitting the quadriceps force to the patellar tendon during knee extension. The patella increases the mechanical advantage of the quadriceps by approximately 50 percent at full extension. Abnormal patellar tracking, trochlear dysplasia, and increased Q-angle contribute to patellofemoral pain syndrome, the most common knee condition in active young people.

Region: Knee

Clinical Relevance

Clinical Notes

Patellofemoral pain syndrome produces peripatellar or retropatellar pain that worsens with sitting for prolonged periods (movie sign), stairs, and squatting. The J-sign of lateral patellar subluxation at the beginning and end of knee flexion is pathological. Patellar apprehension with lateral displacement confirms instability. Treatment addresses the entire kinetic chain including hip abductor and external rotator strengthening, quadriceps VMO training, and patellofemoral taping or bracing.

Pathology

Common Injuries & Conditions

Patellofemoral Pain Syndrome

Anterior knee pain from abnormal patellofemoral loading in active individuals, worsening with sitting, stairs, and squatting, managed with quadriceps and hip strengthening, taping, and activity modification.

Patellar Dislocation

Lateral displacement of the patella from the trochlear groove, almost always injuring the medial patellofemoral ligament, managed conservatively for first events and surgically for recurrent instability.