Abstract
Introduction: The need to meet the demands for a hip replacement that will allow young patients to maintain a high activity level with the expectation of enhanced longevity has been the Holy Grail of modern orthopaedic practice for some time. Novel bearing surfaces and methods of component fixation have not as yet managed to sate this need. The Birmingham Hip Resurfacing (BHR) offers a number of theoretical advantages for this demanding patient group. The metal on metal bearing couple facilitates fluid film lubrication and thus minimises wear and reduces osteolysis. The large head size enhances stability minimising the risk of dislocation during strenuous activity. Resurfacing anatomically restores hip geometry facilitating normal hip biomechanics. Finally, in the event of failure preservation of bone stock makes revision surgery less challenging.
In the absence of long-term outcome studies for the BHR these advantages remain theoretical. Furthermore, reports of good short and medium term results require corroboration at independent centres. This paper presents early results in a large series of patients in such an independent unit.
Patients and Methods: Between March 1999 and December 2001, 102 patients were deemed suitable for hip resurfacing. Patients were felt to be suitable if they were active, had no comorbid conditions that might compromise bone quality and were sixty five years old, although this was not an absolute figure. Pre-operative work up was performed to exclude generalised disease that might compromise bone quality, including bone density measurement where appropriate. Baseline Harris hip scores were performed preoperatively and at latest follow up. Operative details were recorded along with per-operative and other complications. Patients were followed up clinically and radiologically at an average of 13 months (range 3–30 months).
Results: There were 86 male and 16 female patients with an average age of 47 (range 28–66) for the men and 48 (range 21–55) for the women. Five patients had acetabular dysplasia as a primary diagnosis, four had AVN, one had post-traumatic arthritis and the remainder had primary osteoarthritis. There were no patients with inflammatory arthritis or severe dysplasia.
Average Harris hip score pre-operatively was 52 (range 25–65). This had improved to 89 at latest follow-up. All operations were performed via an extended posterior approach. No patients had neuro-vascular complications. Average hospital stay was 6.5 days; average transfusion requirement was 0.3 units.
There were two spontaneous femoral neck fractures, both presenting with pain at approximately 2 months. Both were revised to conventionally stemmed femoral components with large metal heads (CorinTM). One patient presented with pain at 8 months and X-rays showed a fractured neck of femur. At revision, pus was found and diagnosis of infection was assumed. It was treated with a one-stage revision.
93 patients said they were very satisfied with their outcome and two were moderately satisfied. All patients who were more than six months post op (67 patients) had returned to their previous work (41 office work, 16 retailing, 10 farming). Twenty-six patients had returned to active leisure pursuits including running, golf, horse-riding and tennis.
Discussion: When considering new advances in arthroplasty, long-term outcome studies are necessary before any firm conclusion can be drawn regarding ultimate efficacy. This study, however, confirms that BHR is safe and gives good short-term results. While there is no substitute for long-term studies, we feel that these early results are encouraging and justify continued work with the procedure in the context of a critical prospective study.
The abstracts were prepared by Mr Ray Moran. Correspondence should be addressed to him at Irish Orthopaedic Associaton, Secretariat, c/o Cappagh National Orthopaedic Hospital, Finglas, Dublin 11.
