IS THE OUTCOME OF BIRMINGHAM HIP RESURFACING INFLUENCED BY GENDER?

Abstract

Introduction: Hip resurfacing has gained popularity for treating young and active patients with arthritis. Recent literature has reported increase revision rate amongst females as compared to males undergoing resurfacing. The aim of this study is to identify any differences in survival or functional outcome between male and female patients treated with metal-on-metal hip resurfacing.

Methods: All procedures performed between July 1997 to July 2003 were extracted from the database and grouped based on gender. 1266 patients (1441 hips, 582 female and 859 male patients) were identified. The preoperative diagnosis, Oxford hip score, component size, post operative complications and revisions were recorded. Failures included revision of either the femoral or acetabular components.

Results: The mean follow up was 5.5 years. There were 52 revisions in total (30 in female and 22 in male group). The 8 year survival in the male and female groups were 96.1% and 91.5% respectively which is significantly different (p=0.0006). The size of the femoral component was significantly associated with revision (p=0.0008). Cox proportional hazard modelling including gender, aetiology and femoral component size identified a diagnosis of osteoarthritis reduced the risk of revision of 0.2 times (p=0.0004). However, SUFE was significantly associated 5.57 times increased risk of revision (p=0.0019). With every millimetre increase in head size there was a reduction in risk of revision of 0.89 (p=0.0098). By inclusion of all variables in this model gender was found not to be significantly associated with failure.

Conclusion: This study demonstrates that although females may initially appear to have a greater risk of revision this is related to differences in the femoral size and pre-operative diagnosis between the genders. Patient selection for resurfacing is best made on size and diagnosis rather than gender.