The effect of collar on aseptic loosening and proximal femoral bone resorption in hybrid total hip arthroplasty.

This study compared proximal femoral bone resorption in hybrid total hip arthroplasty cases that had poor or good contact between the collar and proximal medial femoral neck. A total of 94 patients (102 hips) comprised the study group. Mean patient age was 52 years, and mean follow-up was 4.86 years. Bone resorption of the proximal femur was evaluated with immediate postoperative and follow-up anteroposterior and lateral radiographs. Statistical analysis using the Mann-Whitney test showed no significant difference between the groups that had good or poor contact. The collar did not prevent calcar resorption even when ideal contact was achieved.