Abstract
Background: Hip resurfacing preserves bone stock on the femoral head. Some authors believe that this is at the expense of sacrificing more bone on the acetabulum and they point out two main reasons for this. Since resurfacing tends to be used in younger and more active individuals a larger head to neck ratio seems desirable in order to provide a better range of movement before impingement. In addition, the acetabular component has to be a minimum of 5 mm thick to prevent deformation on implantation and the subsequent compromise in the congruency of the bearings.
Method: We report the average size of the acetabular components of 220 Cormet resurfacings and 199 Pinnacle cups implanted in our department over a period of 18 months. From these sizes we estimated the mean acetabular bone loss for each procedure.
Results: The mean cup size was 53.7 mm for Cormet and 54.1 mm for Pinnacle i.e. the acetabular component of the resurfacing was smaller than the equivalent uncemented total hip replacement.
Conclusions: These figures show that resurfacing arthroplasty does not necessarily lead to greater acetabular bone loss than a total hip replacement. In our practice, we concentrate upon preserving acetabular bone rather than establishing a large head to neck ratio. In spite of this approach, the occurrence of impingement and dislocation among our patients seems to be as rare as in other comparable series.
Correspondence should be addressed to Ms Larissa Welti, Scientific Secretary, EFORT Central Office, Technoparkstrasse 1, CH-8005 Zürich, Switzerland
