Medial Patella Luxation

Medial patella luxation is a congenital (born with) defect affecting the knee joint of, most commonly, small breed dogs. The knee cap (patella) normally glides within a groove in the femur (large bone above the knee). When this groove is not deep enough, the patella slides in and out of the groove and causes instability of the knee. Medial refers to the direction the knee cap slides out of the groove, i.e.: toward the middle; Patella is the knee cap; and Luxation is the medical term describing a bone coming out of the joint space. The joint instability caused by the luxation leads to other soft tissue injuries in the knee (e.g.: cruciate ligament and meniscal tears). MPL is diagnosed on physical examination. Your veterinarian will take x-rays of your dog’s knee to evaluate the joint more closely. Treatment for MPL varies depending on the degree of affliction. Mildly affected dogs can be treated conservatively with weight management and nutritional supplements to promote joint health. More severely affected patients greatly benefit from surgery to correct the anatomical defect. Surgical correction deepens the groove in the femur, where the patella rests, to prevent luxation and restore joint stability.