MPFL is strong ligament that attaches inside border of the knee cap to the inside of medial femoral condyle (inside of the knee). It helps in keeping the knee cap in a shallow groove on top of the thigh bone. It is often injured in dislocations of the knee cap and is relatively more common in patients with laxity of ligaments. It can predispose to frequent dislocations of the knee, which may cause damage to the cartilage (gristle) on the undersurface of the knee-cap.

The diagnosis is clinical with the history of recent knee-cap dislocation. It can be confirmed with MRI scan or at an arthroscopic (key-hole surgery) examination. If symptomatic, this is usually reconstructed. In our practice, we often use Hamstring Tendon graft to reconstruct MPFL. Though other grafts may be substituted in certain circumstances.