Abstract
Introduction: The Gemini stem (DePuy) is a titanium femoral stem with a modular cobalt chrome femoral head. It has a roughened proximal surface finish to enhance cement bonding and a distal centraliser.
Purpose of the study: A retrospective assessment of the performance of the titanium cemented Gemini femoral component
Patients and Methods: 196 patients underwent a 204 total hip replacements using a titanium cemented Gemini stem and an uncemented cup. All the operations were performed by a lateral approach using modern cementing technique. Patients were assessed clinically (Harris hip score) and radiologically (standard AP and lateral x-rays)
Results: 11 patients with incomplete clinical and radiological follow-up were excluded from the study, leaving 185 patients (193 hips). 36 patients died with their total hip prosthesis in situ. The average age was 71 years and primary diagnosis was OA in the majority. The average follow-up was 70 months (range 35– 121). 29 of the hips have been revised. A further 11 were recognized as radiological failures. In 24, aseptic loosening or a broken stem was an indication for the revision. Mean time to revision was 3.1 years (range 1.5 to 7).
Discussion: Our results indicate that there is a high incidence of early failure associated with these titanium cemented stems, a cumulative failure of approximately 20%. The rough surface finish, titanium alloy and a fixed distal centraliser may all contribute to the early failure by increasing the stresses in the cement. Based on our experience, the continued use of this cemented stem is no longer justified.
The abstracts were prepared by Professor Jegan Krishnan. Correspondence should be addressed to him at the Flinders Medical Centre, Bedford Park 5047, Australia.
