Abstract
Precise femoral component setting is important for smooth patella tracking and good ligament balance in total knee arthroplasty. Most surgeons often use the posterior condylar line (PC line) and set the femoral component of the implant at 3° external rotation from the line. In contrast, some reports recommend using the transepicondylar axis (TEA) of the patient as the indicator. We report a new radiographical technique for assessment of TEA of the femur in total knee arthroplasty. The patient lies in the supine position, and flexes the knee as much as possible. The X-ray is applied to the knee at right angles to the skin. We measured the external rotation angle between the PC and clinical TEA lines, and the internal rotation angle between the clinical TEA and anterior condylar lines (AC line) in 34 patients (43 knees). The former angle was 5.6°±2.8° and the latter was -6.3°±2.9°. Both angles had almost the same values as the ones measured on CT scans and Kneeling View radiographs. Our new radiographical technique seems useful for assessment of the transepicondylar axis of the femur in total knee arthroplasty.
