2010 Volume 29 Issue 1 Pages 39-44
Objective: The BICON-PLUS cup is an uncemented, threaded acetabular component. We evaluated the clinical results of the cup in revision surgery after failed bipolar hip arthroplasty.
Methods: In our institute, 71 hips underwent revision surgery for failed bipolar hip arthroplasty. A total of 30 hips in 25 patients were revised using the BICON-PLUS cup. Among them, we evaluated 24 hips in 21 patients with 2 or more years’ follow-up. All patients were women, and the average age at revision was 57 years. The average period of follow-up was 6 years. During the surgery, morselized allograft bone was filled and impacted into the bone defect, and then the cup was twisted into the bony acetabulum.
Results: The average hip score was 64 points before revision surgery and 84 points 2 years postoperatively. At the final follow-up, seven cups were unstable radiologically. Six hips required repeat revision among the unstable hips. Five hips were revised because of the varus migration of the cup and one hip because of recurrent dislocation. The score had improved to 84 points at 2 years after the repeat revision.
Conclusion: The varus and the repeat revision cases had a severe thinning in the anterior or posterior column, a huge bone defect, or an intraoperative fracture in the acetabulum. Most patients with failed bipolar hip arthroplasty had a severe bone defect in the acetabulum due to outer head migration and/or osteolysis. In addition, the quality of the acetabulum was poor. We suspected that the initial fixation was not adequate as the fins of the cup did not bite into the bony acetabulum. Moreover, the allograft bone could not provide adequate bearing against the load. In conclusion, the indication of the cup for use in failed bipolar hip arthroplasty should be limited to hips with minimum damage in the acetabulum.
