Long-Term Clinical Results of Calcar Loading with Lateral Flare Anatomic Cementless Stem in Patients Younger Than 50 Years

Introduction The purpose of this study was to evaluate the long-term clinical results (minimum 20 years) the ultra-short anatomic cementless stem in patients < 50 years of age. Materials and Methods We reviewed the 336 patients (421 hips) who had a cementless total hip arthroplasty (THA) in patients < 50 years (46 ± 3 years) at the time of surgery. The most common diagnoses were osteonecrosis (47%) and developmental dysplasia (37%). Demographic data, the Harris hip score, Western Ontario and McMaster Universities Osteoarthritic Index (WOMAC), and the University of California, Los Angeles (UCLA) activity scores were recorded. The minimum follow-up interval was 20 years (mean, 21.5 years; range, 20 to 24 years). Results At the time of final follow-up, the mean Harris hip score, WOMAC score, and UCLA activity score were 93 points, 15 points, and 8 points, respectively. All but 7 patients had no thigh pain at the final follow-up. Seven hips (1.7%) had aseptic loosening of the stem. Survival rate at 24 years after the operation was 99.1% for the acetabular component and 96.4% for the femoral component. Conclusions These results in patients < 50 years of age suggest that this calcar loading with lateral flare anatomic cementless hip prosthesis provides good long-term fixation. Moreover, the alumina ceramic-on-alumina ceramic bearing provides a high rate of survivorship without osteolysis.