Abstract
Introduction: Hip instability is a complex and challenging problem. In experienced units, up to 4% of patients undergoing total hip arthroplasty will require revision surgery to treat hip instability, with only 60% of these treatments being successful. Many authors reporting results with various constrained systems available have described dislocation rates post implantation of the constrained component of 4% to 29%.
Method: The thirteen patients who underwent placement of a constrained component as a revision procedure in our unit from 1989 to 2000 were reviewed.
Results: The indications for revision surgery included recurrent dislocation in eight and intraoperative instability in five revision hip arthroplasties. No patients were lost to follow up. The average follow-up was 43 months(range 14 to 121). The average age at time of surgery was 73 years(range: 52 to 84 years). No component has been revised. The average hip score after revision surgery was 72(range: 52 to 89). There have been no episodes of dislocation of the constrained arthroplasty. In seven cases the constrained arthroplasty was implanted into a previously placed well fixed shell.
Conclusion: Constrained acetabular components were a highly effective tool in the treatment of hip instability.
The abstracts were prepared by Professor A. J. Thurston. Correspondence should be addressed to him at the Department of Surgery, Wellington School of Medicine, PO Box 7343, Wellington South, New Zealand
