Long-term clinical and radiographic results of the cementless Spotorno stem in Japanese patients: A more than 15-year follow-up.

PURPOSE: Although previous studies have reported encouraging results of cementless Spotorno (CLS) stem, studies with more than 15 years of follow-up are rare. The objective of this study is to investigate the long-term results of CLS stem and the factors potentially influencing the outcomes.

METHODS: The clinical and radiographic data of 79 hips (64 patients) were reviewed. Clinical outcome was determined using the Japanese Orthopedic Association's hip scoring system (JOA hip score). Survival rate was assessed by Kaplan-Meier survival analysis. The main end point for survival analysis was revision of stem. The correlations between patient demographics, radiographic factors, and stem survival rates were analyzed.

RESULTS: At a mean follow-up period of 20.1 years, the mean JOA hip score at final follow-up was 84.7 points. Stem survival rate for all revisions was 97.5% at 20 years, and stem survival for aseptic loosening was 98.9%. Varus alignment had a significant negative influence on the survival of the femoral stem.

CONCLUSION: This study demonstrates acceptable long-term clinical and radiographic results of the CLS stem in Japanese patients. Caution should be exercised to avoid varus stem alignment.