Dislocation of the Knee

Dislocation of the knee is the most severe form of ligamentous knee injury that involves rupture of the anterior cruciate ligament (ACL). The knee is said to be dislocated when the tibial and femoral articular surfaces have lost contact with each other or may have lost contact based on an existing instability. Knee dislocations are designated anterior or posterior according to the direction of tibial displacement with respect to the femur. Other forms such as medial, lateral, or rotary are far less common and are often combined with anterior or posterior dislocation.