Rotational profile of lower limb and axis for tibial component alignment in varus osteoarthritic knees.

The purposes of this study were to describe the changes in tibial torsion and knee rotation in varus osteoarthritic knees and to check the reliability of reference axis, for tibial component placement, based on femoral transepicondylar axis in these patients. A secondary goal was to determine which reference axis based on proximal tibia is most accurate for determining tibial component rotation. Fifty-two varus osteoarthritic knees and 20 normal knees were analyzed using computed tomographic scan. Tibial torsion and knee rotation were significantly reduced in patients with osteoarthritis. Reference axis based on posterior tibial condyles was most accurate and least variable for tibial component alignment. A significant negative correlation was found between knee rotation and tibial axis based on transepicondylar axis (r = -0.485).