THE CARTILAGINOUS FEMORAL SULCUS IN CHILDREN WITH PATELLAR DISLOCATION - AN ULTRASONOGRAPHIC STUDY

One hundred and sixteen knees of 33 patients with patellar dislocation and 25 normal children 12-18 years of age were examined by ultrasonog raphy to measure the cartilaginous sulcus angle on the patellar surfac e of the femur. In knees with patellar dislocation, the cartilaginous sulcus angle measured between 154 and 195 degrees, exceeding the corre sponding values of normal knees (134-153 degrees). In patient knees, t he cartilaginous sulcus was also consistently wider than the underlyin g osseous sulcus. This suggests that in pediatric patients with patell ar dislocation, the actual patella-stabilizing ability of the femoral sulcus is weaker than the osseous outline in axial radiographs would l ead one to suppose. It would appear also that by measuring the cartila ginous sulcus angle of the femur, a clear distinction can be made betw een normal knee joints and joints displaying patellar instability.