Hip resurfacing is a type of hip replacement which replaces the surfaces of the hip joint. The procedure preserves more bone than a total hip replacement. The head of the femur or 'ball' is not removed but is reshaped to allow a metal cap to be cemented on top of it. The surface of the acetabulum “the socket” is also replaced with a metal implant which is wedged directly into the bone. The resurfacing is made of a cobalt chrome which is highly finished to produce very low wear rates.