Fig. 1

Angular measurement and mechanical axis zones. (a mLDFA: the lateral mechanical angle of the distal femur. MPTA: the medial angle of the proximal tibia. b Dividing the knee into 6 areas, the mechanical axis (dotted line) in zone 1 (lateral zone) or – 1 (media zone) was considered fully corrected, in zone 2 (lateral zone) or – 2 (media zone) was considered partially corrected, and in zone 3 (lateral zone) or – 3 (media zone) was considered uncorrected)