Fig. 2
Receiver operating curve analysis for predicting prosthesis loosening. Top, femoral component. Optimal results for CFRmax was 0.72 (area under the curve [AUC] = 0.77), and for CFR0.7 length was 2 cm (AUC = 0.83). Bottom, tibial component. Optimal results for CFRmax was 0.83 (AUC = 0.66), and for CFR0.7 length was 4.2 cm (AUC = 0.74). CFR (canal filling ratio) was calculated as the ratio between the stem width and the medullary canal width. CFRx length indicates the stem length for which CFR is larger than x. CFRmax indicates the maximum CFR over the entire length of the stem