COMPARISON OF COLLARED AND COLLARLESS FEMORAL COMPONENTS IN PRIMARY UNCEMENTED TOTAL HIP-ARTHROPLASTY

Two hundred three consecutive primary uncemented total hip arthroplast ies were prospectively randomized using collared and collarless versio ns of an identical titanium stem. Identical 28-mm titanium heads were implanted in all cases. One hundred three collared hips were compared with 100 collarless hips. Follow-up periods averaged 45.7 months in bo th groups. Intraoperative, early and late complications were similar. Hip scores, including thigh pain, at final follow-up visit were also s imilar. No significant differences were noted in acetabular or femoral radiolucencies, subsidence, osteolysis, or proximal femoral remodelin g. At 5 years, more collarless stems revealed pedestal formation (57.1 % vs 33.9%). The presence of a collar had no effect on the adequacy of fixation, proximal femoral osteopenia, or clinical scores at 5 years.