Hip replacement: landmark surgery in modern medical history.

Total hip replacement (THR) is most often performed to treat end-stage symptomatic osteoarthritis. Patients typically present with increasing pain, restricted mobility and stiffness. In this procedure, the femoral head and part of the femoral neck are excised. The acetabulum is enlarged and an acetabular cup is inserted. The femoral head is replaced by a femoral component, the stem of which is inserted into the medullary canal of the femur. The components can be either cemented in place or press-fit (cementless). The THR concept was popularised by Sir John Charnley in the 1960s and although, over half a century of development has resulted in incremental improvements, the procedure is not dramatically different from the one he described. However, over the last two decades there have been significant changes in the types of bearing surfaces used. Metal on polyethylene continues to be the workhorse for the majority of cases. In the young and active, bearing surfaces with low wear rate are increasingly used. Since the early 1960s, THR has played an important role in alleviating pain and restoring mobility to millions of people. The cost-effectiveness of THR in treating advanced osteoarthritis makes it one of the most successful of all surgical interventions.