Fig. 3

Comparison of the 3D rotation angle among OA grades in both the supine and standing positions. An asterisk (*) indicates a significant difference (p<0.05), a double asterisk (**) indicates a significant difference (p<0.01). A In the supine position, the knee joint flexed and adducted in the high K-L grade group compared to the low K-L grade group, but there was no significant difference in rotation. B In the standing position, the OA knee joint flexed and adducted in the high K-L grade group, and the tibia was originally externally rotated with respect to the femur but gradually internally rotated in the high K-L grade group