We present a case of superior dislocation of the patella trapped by interlocked osteophytes. Unlike previous reports, in which the mechanism resulted from a blow to the inferior pole, it is postulated that increased load on the extensor mechanism, combined with patella alta and patellofemoral osteophytes, caused locking of the knee in extension.

After total knee replacement a 57-year-old woman developed increasing pain in her left calf on exercise. This was due to erosion of the popliteal artery by a spur of cement. Removal of the spur with resection and Dacron grafting of the damaged section of the vessel cured her symptoms.