Figure 3

(a) Youden’s J statistic curve (blue) used to determine the score threshold. Optimal score threshold = 0.81 (J statistic = 0.36) is indicated by the dashed lines. (b) Receiver operator curve (blue) for prediction of revision surgery from load score dichotomization (area under the curve = 0.67). At the J statistic-determined threshold of 0.81, the false positive rate = 0.48 and true positive rate = 0.83.