At what degree of knee flexion is the MPFL at its tightest to stabilize against lateral patella displacement?

The medial patellofemoral ligament (MPFL) is crucial for stabilizing the patella and preventing lateral displacement. Its tension varies with the angle of knee flexion, influencing its effectiveness in stabilizing the patella.

In the range of 0-30 degrees of knee flexion, the MPFL is at its tightest. This is significant because the MPFL provides the most support to the patella during this initial phase of flexion when the patella is still primarily situated in the intercondylar notch of the femur. As the knee flexes beyond this range, the patella begins to track more laterally, and the tension in the MPFL decreases, making it less effective in resisting lateral forces.

This understanding is fundamental for diagnosing and treating patellar instability and is integral to surgical approaches, as it helps clinicians determine the appropriate interventions based on the knee’s position and the MPFL's functional capacity at various degrees of flexion.