DISLOCATION AFTER HEMIARTHROPLASTY OF THE HIP - A COMPARISON OF THE DISLOCATION RATE AFTER POSTERIOR AND LATERAL APPROACHES TO THE HIP

We compared the 3-month dislocation rate for hip hemiarthoplasties ins erted via the posterior and direct lateral routes. In all, 2906 primar y hemiarthroplasties, performed between 1986 and 1992 in four hospital s on a training hospital rotation, were analysed. The posterior approa ch was used in 1656 (57%) and the lateral in 1250 (43%). The groups we re otherwise comparable. The overall dislocation rate for the posterio r approach was 9.0% (149/1656), whereas that for the direct lateral ap proach was 3.3% (41/2150). The difference is statistically highly sign ificant. In addition, we analysed the dislocation rate for each approa ch in the three broad groups of surgical trainee. For senior registrar s, there was no statistical difference in the dislocation rate. Howeve r, for registrars and senior house officers, there were statistically highly significant differences in the dislocation rate for posterior a nd direct lateral approaches (8.4% vs 3.3% and 14.2% vs 3.6%, respecti vely). We conclude that, because of the high mortality associated with dislocation of a hemiarthroplasty, the posterior approach for this op eration should now be abandoned, especially by surgical trainees early in their careers.