Lateral Patellar Instability and the Medial Patellofemoral Ligament (MPFL)

Lateral patellar instability occurs when the kneecap dislocates out of place. The kneecap or patella is a small bone in the front of the knee. It glides along the femoral groove (a groove in the femur bone) as the knee bends and straightens. If the patella comes out of the groove completely, it is referred to as patellar dislocation. If the patella comes out of the groove partially, it is referred to as patellar subluxation.

Symptoms of dislocations of the kneecap are as follows:

-          Pain at the knee joint
-          Swelling
-          Obvious displacement of the kneecap (kneecap can often briefly dislocate and return, but pain and swelling will still be present)

When the kneecap dislocates, it often tears the medial patellofemoral ligament on the inside of the knee. The MPFL is a thin band of tissue that attaches the kneecap to the inner part of the knee. The medial patellofemoral ligament or MPFL is important for stability in the knee.

There are surgical and non-surgical treatments for patellar instability. Rest, ice and bracing have been known to heal the injury and prevent recurrent dislocations. However, surgical intervention is sometimes needed to correct recurrent dislocations.

If the MPFL is torn, the patient can potentially benefit from a surgical procedure known as MPFL reconstruction. Reconstruction of the MPFL is a surgical procedure that restores patellofemoral stability. The most successful and widely accepted approach to this procedure is to use an approach that restores the MPFL to its anatomically correct position. This procedure, along with other options, such as tibial tubercle osteotomy, and/or a trochleoplasty can be used to correct the problem. The exact treatment protocol varies by individual.