A Comparison of Coronal Plane Axial Femoral Relationships in Asian Patients With Varus Osteoarthritic Knees and Healthy Knees

Standing full-length radiographs were measured to compare coronal femoral axes between 250 limbs in patients with varus osteoarthritis with 50 healthy controls. Mean distal femoral axis-mechanical axis angle was 7.3 degrees +/- 1.6 degrees, and mean femoral bow was 3.6 degrees +/- 2.5 degrees in patients compared to 5.5 degrees +/- 0.8 degrees and 0.4 degrees +/- 1.2 degrees, respectively, in controls. Femoral condylar-mechanical axis angle was significantly lower in osteoarthritic limbs (89.9 degrees + 2.8 degrees) as compared to controls (93.1 degrees + 1.6 degrees). Varus deformity correlated significantly with femoral bowing (P < .05; correlation coefficient, 0.4). Osteoarthritic limbs (18.8%) showed a distal femoral axis-mechanical axis angle more than 9 degrees. These findings have implications in deciding the optimum valgus angle at which to perform distal femoral resection in total knee arthroplasty.