In a 10-year prospective study, 561 displaced subcapital fractures of the femoral neck in 546 patients were treated with the Hastings bipolar hemiarthroplasty. Within six months of their operations, 148 patients had died. In 322 hips followed up, 243 with adequate serial radiographs separated by more than one year, only 14 (5.6%) showed acetabular erosion. A group of 91 had been reviewed for between three and nine years (mean, 4 years 10 months) and of these, 95% had no pain or slight pain only. Comparison with an earlier series of conventional hemiarthroplasties reported from this institution showed that the clinical results were similar, but that the erosion rate had been halved.

The best treatment for a fractured neck of femur in an old person is considered by many to be replacement hemiarthroplasty which allows the patient to walk immediately on a stable, painless hip. The late results can be marred by acetabular erosion in which the metal head of the prosthesis erodes upwards into the acetabulum to give pain and disability. Here the trial of a new bipolar prosthesis with a dynamic self-aligning outer head is described in 161 fractured necks of femur. No acetabular erosion has been seen with its use over four years.