Long-Term Outcomes of the Bi-Metric Proximally Hydroxyapatite-Coated Femoral Stem

Abstract

Purpose Promising clinical results and survival rates have been reported for the Bi-Metric proximally hydroxyapatite (HA)-coated femoral stem in short- and mid-term studies. In this study we evaluated the long-term survival as well as clinical and radiological results of this stem. Methods From 1992 to 1998 we prospectively included 112 consecutive patients who received a total hip arthroplasty (THA) with an uncemented proximally HA-coated Bi-Metric femoral component (Biomet). At 3 months, 1 year and thereafter every 2 to 3 years, patients were clinically and radiologically monitored. Primary endpoint was revision of the stem for any reason. Secondary endpoints were survival of the cup and THA, radiological characteristics and clinical scores (HHS, HOOS, SF-36 and VAS). Results Median follow-up was 20 (16-22.25) years. Median age at surgery was 52 (22-63) years. At final follow-up, survival analysis showed an all-cause stem survival of 96.8% (95% CI, 93.3-100). Median HHS scores improved from 57 preoperatively to 94 at final follow-up (p<0.001). At final follow-up the median HOOS score was 80 (9-100); median SF-36 score 71 (18-100); median VAS pain score at rest 0 (0-6) and during activity 0 (0-10). Conclusions In this prospective cohort study the 20-year survival rate of the Bi-Metric proximally HA-coated femoral stem was excellent.