INITIAL RESULTS OF THE BIRMINGHAM HIP RESURFACING IN NZ: COMPARISON TO CONVENTIONAL THR WITH HARD ON HARD BEARING

Abstract

The Birmingham Hip Resurfacing (BHR) has become increasingly popular for young active patients with severe OA of the hip. Although it has been in use in the UK since 1991, none were performed in NZ until late 2004. We have reviewed our initial results & have compared them to a similar group of patients who received conventional total hip replacement (THR) with ceramic-on-ceramic bearings.

All patients aged 65 years or less undergoing either BHR or ceramic-on-ceramic THR under the care of the 2 senior authors (DRT & SAE) between October 2003 & July 2006 were included in the study. Patients were assessed pre- & post-operatively clinically & by questionnaires including the Harris Hip (HH) score & modified University of California Los Angeles (UCLA) activity score. Patients were also asked about activity levels prior to their hip symptoms.

59 BHR (38 resurfacings & 21 modular) and 55 THR were performed. 3 BHR & 1 THR patients were not able to be reviewed giving 97% follow up at 6–39 months. 3 patients had minor superficial wound infections (1 BHR & 2 THR). 1 BHR dislocated in recovery but has since been stable. 1 BHR has recently been revised for deep infection. We have had no peri-prosthetic fractures. BHR patients were slightly younger & were more active than the THR patients both pre- and post-operatively. Both group’s HH & UCLA scores improved significantly with surgery. BHR patients had a slightly greater improvement in HH score, but this failed to reach significance. When patients with single joint disease were considered, THR patients remained less active than prior to their hip symptoms whereas the BHR group’s activity scores matched their pre-disease level. All but 2 BHR patients and all of the THR patients were satisfied with their result at the time of review.

Our initial experience with the BHR has been positive. Although we have achieved excellent results with both the BHR and with ceramic-on-ceramic THR, the results of the BHR do seem superior in relation to post operative activity levels. The two groups were, however, non-randomised and did differ with respect to age & activity levels, so these comparative results should be interpreted with some caution.