(Science: orthopaedics) A condition where the knee cap (patella) rubs on the surface of the femur rather than following its normal tracking over the knee joint. This condition is brought about by stress or overuse (for example runners). Running on hills or incline surfaces can exacerbate this problem.
treatment includes rest and stretching exercises for the quadriceps and hamstring muscles. Strengthening the medial (inner) head of the quadriceps (along the inner thigh) will help pull the knee cap medially and correct the problem.