Favorable midterm results of total hip arthroplasties with a lateral flare uncemented stem.

Overview

UNLABELLED: Uncemented stems have been advocated for primary total hip arthroplasties in the young active population. We evaluated the clinical and radiographic results of total hip arthroplasties with a customized lateral flare cementless femoral stem in a prospective, consecutive series of 35 patients (40 hips) younger than 55 years at the time of surgery and who were followed up for an average of 9.2 years (range, 5.7-12.2 years). The study group comprised 20 men and 15 women with an average age of 45.2 years (range, 30-55 years). One patient had aseptic loosening of the stem and one patient had a deep infection. The mean preoperative Harris hip score was 47 and at the latest followup it was 97. The mean axial migration was 0.51 mm. Femoral osteolysis was found to be circumscribed to the proximal femur in Gruen Zones 1 (15%) and 7 (8%) in patients with accelerated polyethylene wear. Radiographic changes consistent with new bone apposition under the lateral flare of the stem in Zones 2, 6, and 7 were found in 73% of the cases. Our data suggest a custom lateral flare stem for primary arthroplasties in the younger patient population achieves excellent clinical results with a low rate of aseptic loosening. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series).