In traditional hip replacements, the top of the thigh bone – the femoral neck and head- is removed and the stem is fixed inside the shaft of the femur. In hip resurfacing the neck and head of the femur are retained and a metal resurfacing prosthesis is fixed onto the head of the femur. A metal cup is inserted into the socket providing a metal on metal articulation. The modern generation of hip resurfacing prostheses have acceptable results for up to 8 years, but the long-term results are not known. Claims have been made that patients can be more active following hip resurfacing, but these remain unproven. Hip resurfacing is no less of an operative procedure as far as the patient is concerned. The same risks apply that exist for total hip replacement. There are also some risks that are isolated to hip resurfacing. Because the femoral neck is retained, there is a risk of neck fracture, requiring revision surgery. It seems as though the femoral neck becomes thinner in some patients with time after hip resurfacing, but the significance of this is not clear. Also the concerns regarding metal on metal articulations also apply. Because of their very large surface area, hip resurfacing prostheses produce a very large number of metal particles – enough to cause local allergic reactions in some patients.

Debate exists as to which patients should be offered hip resurfacing. We would not advocate hip resurfacing for women of child bearing age, females with osteoporosis (because of the risk of femoral neck fracture), patients on steroid medication, patients presenting with inflammatory arthritis or any patient with a very deformed femoral head. In all other patients hip resurfacing would be discussed and the pro’s and cons of this procedure in each individual case would be considered. Patients must be aware that if a hip resurfacing fails, then changing it to a total hip replacement, although bone may have been preserved, is still a major revision procedure with significant risk of complications to the patient.