Clinical Overview
Reviewed by Dr. Jack Farr

Three bones meet within the knee joint: the femur, or thighbone, the tibia, or shinbone, and the patella, the kneecap. The joint is stabilized by connective tissues known as ligaments, which connect bones to bones within the body.

Because of trauma or laxity (looseness) of the ligaments in the knee, the kneecap may slide out of the groove it rests in. When it does so, but doesn't leave the joint completely, a patient experiences subluxation. If the patella becomes completely dislodged from the joint, it is known as dislocation.

Causes

Injuries such as a falls, off-centered landings, or other sport-related injuries cause most dislocations. Laxity, otherwise known as looseness of the joint or double-jointedness, may raise the risk for dislocation.

Risk Factors

Contact sports, or sports involving quick motion, twisting, or pivoting can lead to knee dislocation. The first time the knee dislocates, the tissue holding the knee in place tears or stretches. As a result, repeated dislocations are a possibility until the problem is remedied. Each time the knee dislocates, it can cause damage to the cartilage and joint. Knee dislocation can contribute to degenerative knee damage and arthritis.

Last updated: Aug-27-07