A comparison of 4 intraoperative methods to determine femoral component rotation during total knee arthroplasty.

A total of 100 consecutive posterior cruciate-retaining total knee arthroplastics were performed in 81 patients with an average age of 69 years by 1 surgeon. Diagnoses included osteoarthritis in 93 knees and rheumatoid arthritis in 7 knees. The femoral alignment necessary to create a rectangular flexion gap was determined and compared with Whiteside's line, the transepicondylar axis, and a line in 3 degrees of external rotation relative to the posterior condyles of the femur. The transepicondylar axis most consistently recreated a balanced flexion space, whereas 3 degrees of external rotation off the posterior condyles was least consistent, especially in valgus knees.