Early failures in large head metal-on-metal total hip arthroplasty.

Abstract

Concerns have recently been raised about large head metal-on-metal total hip arthroplasties (LDH THA). Metal ion release due to wear may cause osteolysis, pseudotumours and necrosis. In addition, fixation of certain acetabular components is thought to be suboptimal. We present the short term outcome of the Durom LDH THA. Retrospectively, a consecutive series of 64 implants in 60 patients was analysed with a mean follow-up of 37 months. Clinical and radiological evaluation was performed on a regular basis, followed by additional evaluations when indicated. The 10-year revision percentage was calculated and compared with National Institute for Health and Clinical Excellence (NICE) standards. Six patients (six hips) underwent cup revision (9%). Four of these cups showed no or minimal bone fixation. Three patients had a pseudotumour. In two revision cases, ALVAL (aseptic lymphocyte-dominated vasculitis-associated lesion) was present. Lack of bone ingrowth and the presence of ARMD (adverse reaction to metal debris) seem to contribute to a high failure rate of the Durom LDH THA. The predicted ten-year revision rate of 14.2% (95% CI 5.6-22.8) is, given the broad confidence interval, not significantly outside NICE recommended standards. However, it is not clear which factors, if any, predict implant failure. Therefore, we do not advocate the use of this implant.