The position of the tibial component affecting the postoperative mechanical axis in total knee arthroplasty.

The purpose is to identify whether the position of the tibial component in relation to the anatomical axis affects the postoperative mechanical axis in total knee arthroplasty for Korean patients. Preoperatively, 30 patients with varus deformity lesser than 10° were classified as group A, and 30 patients greater than 10° were classified as group B. Postoperatively, the distance between the midline of the tibial stem and anatomical axis (medial offset) was measured. The medial offsets were 2.5±1.9 mm in group A and 3.9±2.7 mm in group B (P=.021). The postoperative mechanical axes were varus 1.3±1.2° in group A and varus 2.5±2.0° in group B (P=.004). We think that the medial position of tibial component in relation to the anatomical axis affects the measurement of postoperative mechanical axis in total knee arthroplasty.