Fig. 1

Surgical planning was performed so that the target point of the postoperative weight-bearing line ratio was 62.5%. First, open-wedge high tibial osteotomy (HTO) was planned. If the opening gap was larger than 13 mm, closed-wedge HTO was planned. If the postoperative mechanical medial proximal tibial angle was over 95° with isolated HTO, double-level osteotomy (DLO) was planned. In DLO, lateral closed-wedge distal femoral osteotomy was performed so that the postoperative mechanical lateral distal femoral angle was 85°, and any residual varus deformity was corrected with HTO