Fig. 3　 Survivorship of stage 3B and stage 4 hips by JMHLW classification

When the end point was total hip arthroplasty, survival at one year was 52.5% in stage 3B and 39.3% in stage 4; survival at two years was 48.8% in stage 3B and 13.5% in stage 4, with a significant difference( Kaplan-Meier and log rank test, p=0.027).