Femoropatellar

The femoropatellar joint, also known as the patellofemoral joint, is the articulation between the patella (kneecap) and the femur. It is a component of the knee joint and helps transmit the forces of the quadriceps to the tibia during knee extension. The joint's articular surfaces are the posterior patellar surface, which has medial and lateral facets, and the trochlear groove (trochlear sulcus) of the distal femur.

During knee movement, the patella slides within the trochlear groove. The contact area and location shift with knee flexion: contact on the lower or odd facet occurs in shallow flexion, while deeper flexion brings contact to the central and medial facets. The patella increases the quadriceps' mechanical advantage by acting as a fulcrum in the extensor mechanism. Stability is provided by the surrounding soft tissues, including the medial and lateral patellar retinacula and the medial patellofemoral ligament, as well as by tibiofemoral joint alignment and trochlear depth.

Clinically, patellofemoral problems commonly present as anterior knee pain. Patellofemoral pain syndrome is a frequent overuse or maltracking condition, especially in young, active individuals. Lateral patellar dislocation or subluxation can occur with trauma or malalignment. Osteoarthritis and chondromalacia patellae involve the patellofemoral joint cartilage, contributing to pain and crepitus. Imaging typically includes skyline/axial radiographs; MRI may assess cartilage and soft-tissue structures.

Management ranges from conservative approaches—physical therapy emphasizing hip and quadriceps strengthening, patellar taping or bracing, activity modification—to surgical options in refractory cases, such as medial patellofemoral ligament reconstruction or tibial tubercle realignment. Treatment aims to improve patellar tracking, reduce joint stress, and restore function.