THE OUTCOME OF BIRMINGHAM HIP RESURFACING AT 10 YEARS

Abstract

We report the survival at ten years of 173 consecutive Birmingham Hip Resurfacing’s implanted between August 1997 and August 1998 at a single institution. Failure was defined as revision of either the acetabular or femoral component for any reason during the study period.

The survival at the end of ten years was 96.5% (95%c. i. 89.1 – 99.5%) The mean age of the patients at implantation was 50 years (range 15 – 75). There were 124 (72%) male cases and 49 (28%) female cases. 123 (71%) cases had the diagnosis of osteoarthritis, 9 osteonecrosis, 5 rheumatoid and 3 DDH. The posterior approach was used in 154 (89%) cases and anterolateral in 19 (11%). Cases were performed by 5 different surgeons.

There were 5 revisions, 9 unrelated deaths and 18 were lost to follow-up beyond 5 years. Two revisions occurred for infection (6 months and 2 years). A revision at 3.5 years for acetabular loosening and two further at 6.4 and 7.9 years due to avascular necrosis of the femoral head and collapse were performed. No other revisions are impending. The median pre-operative oxford hip score was 61% (IQR 48–73) and the median 10 year score was 7% (IQR 0–31) for 110 completed forms.

Further analysis of the total resurfacing database at this institution of 2775 cases was performed. Cox-proportional hazard analysis identified that component size and pre-operative diagnosis were significantly associated with failure. Although females may initially appear to have a greater risk of revision this is related to differences in the size and pre-operative diagnosis between the genders. This study confirms that hip resurfacing using a metal-on-metal bearing of known provenance can provide a solution in the medium term for the younger more active adult who requires surgical intervention for hip disease.