PurposeThe changes in the lower limb alignment were vitally important after high tibial osteotomy (HTO). Therefore, the purpose of present study was to analyze the characteristics of plantar pressure distribution after HTO, and to investigate the effect of plantar pressure distribution on postoperative limb alignment.MethodsBetween May 2020 and April 2021, varus knee patients undergoing HTO were evaluated in the present study. The peak pressure of plantar regions, medial-lateral pressure ratio (MLPR), foot progression angle (FTA), anteroposterior COP (AP-COP), lateral symmetry of COP (LS-COP), and the radiographic parameters were evaluated preoperatively and at the final follow-up. Compared among the slight valgus (SV), moderate valgus (MV) and large valgus (LV) groups at the final follow-up, the peak pressure of HM, HC and M5 regions, and the MLPR were compared; the Knee Injury and Osteoarthritis Outcome Score4 (KOOS4) including four subscales, and the American of orthopedic foot and ankle society (AOFAS) were evaluated.ResultsThe WBL%, HKA and TPI angle changed significantly after HTO (P< 0.001). The preoperative group exhibited a lower peak pressure in the HM region (P< 0.05) and higher peak pressure in the M5 region (P< 0.05); the pre- and postoperative groups exhibited a lower peak pressure in the HC region (P< 0.05); the rearfoot MLPR was significantly lower and LS-COP was significantly higher in the preoperative group (P= 0.017 in MLPR and 0.031 in LS-COP, respectively). Comparison among the SV, MV and LV groups, the SV group indicated a lower peak pressure in the HM region (P= 0.036), and a lower MLPR in the rearfoot (P= 0.033). The KOOS Sport/Re score in the MV and LV groups increased significantly compared with the SV group (P= 0.042).ConclusionPlantar pressure distribution during the stance phase in patients with varus knee OA following HTO exhibited a more medialized rearfoot plantar pressure distribution pattern than that before surgery. Compared with the small valgus alignment, a moderate to large valgus alignment allows patients to walk with a more even medial and lateral plantar pressure distribution, which is more similar to healthy adults.