Figure 3

(A) The receiver operating characteristic curve of preoperative hemoglobin level, and cardiac disease in unilateral total knee arthroplasty (TKA). This curve indicate that the cut off value of preoperative hemoglobin as 11.8 g/dL (red dot, AUC 0.877, sensitivity 85%, specificity 73.1%). (B) The receiver operating characteristic curve of preoperative hemoglobin level, and cardiac disease in bilateral staged (1 week apart) TKA. This curve indicate that the cut off value of preoperative hemoglobin as 12.8 g/dL (red dot, AUC 0.760, sensitivity 71%, specificity 70.2%).