The medial patellofemoral ligament is a part of the complex network of soft tissues that stabilize the knee. The MPFL attaches the inside part of the patella (kneecap) to the long bone of the thigh, also called the femur. (Together, the patella and femur compose the patellofemoral joint.) Injury to this ligament can occur when the patella dislocates or becomes subluxated (partially dislocated) due to a trauma experienced during athletics or an accident, as a result of naturally loose ligaments or due to individual variations in bony anatomy. MPFL reconstruction is a surgery in which a new medial patellofemoral ligament is created to stabilize the knee and help protect the joint from additional damage.