Fig. 2From: Nomogram to predict collapse-free survival after core decompression of nontraumatic osteonecrosis of the femoral headCalibration plot comparing predicted and actual collapse-free survival probabilities at 3-year follow-up. The 50-sample bootstrapped calibration plot for the prediction of 3-year collapse-free survival is shown. The gray line represents the ideal fit; circles represent nomogram-predicted probabilities; the cross represents the bootstrap-corrected estimates; and the error bars represent the 95% CIs of these estimatesBack to article page