Total hip replacement. Coloured X-ray of the pelvis of a 74 year old woman, showing two hip replacements. Each replacement hip consists of a ball and shaft (red), attached to the top of the femur (thigh bone). One of the replacements also has a prosthetic socket (brown), which has been fitted into the pelvis (centre right). This procedure is called a trochanteric osteotomy, which is where the hip joint is accessed via removal of part of the hip bone (the trochanter). Although this procedure has the advantage of preserving the anatomical integrity of abductor muscles, the grafting of the bone back on to the shaft of the femur with metal wires (red) is not always successful. This failure to graft results in a state known as non-union, which is seen here.