Comparison of femoral bone remodeling after total hip arthroplasty with cementless short-tapered wedge stem and fully hydroxyapatite-coated stem.

ABSTRACT

INTRODUCTION: We aimed to compare periprosthetic femoral bone remodeling after cementless total hip arthroplasty (THA) using a short-tapered wedge stem and a fully hydroxyapatite (HA)-coated stem. MATERIALS AND METHODS: In this retrospective study, 24 primary cementless THA procedures with short-tapered wedge stem and 24 using a fully HA-coated stem were performed. The follow-up duration was 2 years for both groups. Clinical evaluation was performed using the Merle d'Aubigné and Postel scoring systems. Standardized anteroposterior radiographs of the pelvis and femur were obtained. Dual-energy X-ray absorptiometry was performed, and the bone mineral density (BMD) around the stem was assessed in each Gruen zone at the first postoperative week as a baseline value and at 6 weeks, 3 and 6 months, and 1 and 2 years postoperatively. RESULTS: The mean Merle d'Aubigné and Postel scores improved significantly postoperatively in both groups. None of the hips showed loosening in either group. Spot welds occurred in zones 1, 2, 6, and 7 in the short-tapered wedge group, and in all zones in the fully HA-coated group. Significant BMD loss occurred only in zone 4 in the short-tapered wedge group, and no significant bone loss occurred in any zone in the fully HA-coated stem group; a significant difference between the two groups was observed only in zone 4 at 2 years after THA. CONCLUSIONS: Clinical and radiographical outcomes in both groups were good, and both stems suppressed postoperative BMD loss at 2 years.