[The medial patellofemoral ligament: function, injury, and treatment].

The medial patellofemoral ligament or MPFL is the prime soft tissue stabilizer of the patella. The MPFL is a non-isometric ligament lying in the second fascial layer of the knee; it is tight in extension and lax in flexion. The ligament is always torn in acute patellar dislocations. As "form follows function" we believe that the MPFL should be reconstructed in such a way that it stabilizes the patella without changing its movement pattern.