Fig. 5From: The SP-ET index is a new index for assessing the vertical position of patellaThe receiver operating characteristic (ROC) curves of SP-ET index and Insall–Salvati ratio. The ROC of SP-ET index was the blue curve (area under curve (AUC) = 0.803); the ROC of Insall–Salvati ratio was the red curve (AUC = 0.699)Back to article page