Coronal Alignment of the Lower Extremity: A Gender-Based Radio-Graphic Analysis in Indian Patients

Variation in the shape of the femur and tibia has been shown to influence hip-kneeankle-axis angle (HKAA) and bears a role in reconstructive surgeries such as total knee arthroplasty (TKA). However, data on the axial alignment of the lower extremity specific to sex largely remains unavailable. Thus, we conducted a study with an aim to measure alignment and calculate differences in both the sexes in Indian population.

The following radiological parameters were measured from weight-bearing long leg radiographs of 966 limbs of Indian subjects via a morphometric software (Matlab R2009a) (1) Hip-Knee-Ankle angle (HKAA), (2) femoral bowing, (3) tibial bowing, (4) condylar plateau angle (CPA). The knees were classified according to the Kellegren and Lawrence grading and the differences between both the sexes were calculated with appropriate statistical tests.

56.04% of the subjects were female. An increase in the mean age was observed for both the genders with an increase in the severity of OA. Height did not show any significant association with the alignment of the limb. The mean HKAA observed was - 5.88° ± 0.35° in females and - 4.99° ± 0.41° in males. The overall mean femoral bow and tibial bow was - 1.26° ± 0.24°, - 1.60° ± 0.18° in females and - 1.09 ± 0.28, - 1.47° ± 0.21° in males. The mean condylar plateau angle was higher in females - 2.67 ± 0.34 as compared to males - 2.35° ± 0.39°. A greater lateral bow was seen in males at higher grades of OA for femur and at lower grades of OA for tibia.

This study provides gender-based differences in the various axial radio-graphic parameters in a long leg radio-graphs in Indian population which might help in a better understanding of the etiopathogenesis of osteoarthritis and also help planning and execution of reconstructive surgeries such as TKA.