FAILURE OF THE MECRING SCREW-RING ACETABULAR COMPONENT IN TOTAL HIP-ARTHROPLASTY - A 3-YEAR TO 7-YEAR FOLLOW-UP-STUDY

We prospectively studied the results of 411 consecutive total hip arth roplasties with a Mecring screw-ring acetabular component inserted wit hout cement combined with a Stanmore femoral stem inserted with cement . The duration of follow-up ranged from three to seven gears (mean, fo ur years and six months). Three hundred and thirty-one patients (378 h ips) were available for physical examination and had a complete set of radiographs. The clinical result was good or excellent for 82 per cen t (309) of the 378 hips. However, the rate of radiographic loosening o f the acetabular component, as evidenced by migration at the most rece nt follow-up examination, was alarmingly high: 25 per cent (ninety-fiv e) of the 378 hips. In general, these patients did not have serious cl inical symptoms. The cups in women migrated significantly more often ( p = 0.003) than those in men. Migration was also more frequent in pati ents who were less than fifty-one years old and in patients in whom th e index procedure was a revision arthroplasty, but these differences w ere not significant. Twenty-one (6 per cent) of the acetabular cups we re revised for aseptic loosening. T he high rate of radiographic loose ning has led us to abandon the use of the Mecring screw-ring acetabula r component.