Fig. 4

Transepicondylar axis angles (TEAAs) were measured by preoperative superimposed CT (a) and a protractor in the operating room (b). a Determination of the recess of the medial epicondyle, the prominence of the lateral epicondyle, and the highest point of the medial and lateral posterior condyles by the MIP approach of CT. The TEAA value was automatically obtained by the in-house program. b Intraoperative measurement required electrocautery to mark the position of the medial and lateral epicondyles on the distal femoral resection surface. The arms of the protractor were parallel to the posterior pedals of instruments and the electrocautery marks