Long-term results of custom-made femoral stems.

BACKGROUND: The progress of 3D imaging and manufacturing of implants has made it possible to achieve a custom-made concept in THA. The custom-made cementless femoral stem provides optimal implant stability combined with restoration of the native hip mechanics. OBJECTIVE: The purpose of this study was to evaluate the long-term survivorship of custom-made hip femoral stems in two populations of patients undergoing THA: patients under 50 years old (young patients group) and patients with high-grade developmental dysplasia of the hip (DDH group). METHODS: A series of 232 primary custom-made cementless THA stems were retrospectively evaluated in patients less than 50 years old at the time of surgery and at follow-up after an average of 20 years. A second series of 26 custom-made cementless stem THAs for late DDH (21 patients) including only Crowe grade III and grade IV were also retrospectively evaluated with an average follow-up of 16 years. The clinical and radiological evaluations were performed preoperatively and at yearly intervals. RESULTS: For the young patient group, the follow-up ranged from 14 to 27 years. The HHS and the Merle D'Aubigne-Postel score significantly improved from preoperatively to a mean of 94.1 (range 48-100) and 15.9 (range 9-18), respectively. Taking stem revision for aseptic loosening as an endpoint, survivorship was 96.8% at 20 years (95% confidence interval, CI 95.1-98.5). For the DDH group, the follow-up ranged from 10 to 22 years. The mean HHS increased significantly from preoperative 49+/- 22 points to the most recent follow-up examination with 86 13 points and survivorship was 96.1% (95% CI, 92.7-99.9). CONCLUSION: Custom-made femoral stems provide good functional outcome and long-term survivorship in two specific populations of patients undergoing THAs: patients under 50 years old with high expectations and patients with high-grade DDH.