[Erosion of polyethylene cupulae. Radiological study of 123 Charnley total prostheses]

The authors have measured the distance between the centre of the femoral component and that of the acetabular component using a ten times magnification radiograph. This technique allows greater precision in the radiological assessment. 123 total hip prostheses were measured after an average follow-up of 131 months. The mean annual wear was 1.1 mm. There was a regular progression throughout the period. These results were comparable with those obtained by other authors. The wear appears to be only half as significant as in prostheses with a 32 mm femoral component (Muller type). The wear was maximal in young male patients. Patients who were overweight did not have any increased incidence of wear.