Abstract: Objective To assess the clinical efficacy of supramalleolar osteotomy (SMOT) in the treatment of varus ankle arthritis using a gait analysis system. 
Methods A retrospective analysis was conducted on 95 patients with ankle arthritis who underwent SMOT at the Department of Foot and Ankle Surgery, Cangzhou Hospital of Integrated Traditional Chinese and Western Medicine in Hebei Province from January 2020 to December 2023. After strict screening based on inclusion and exclusion criteria, 78 patients were finally included. Preoperative and postoperative data on gait analysis, American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot Score, visual analogue scale (VAS) pain scores, tibial articular surface angle (TAS), and tibial lateral surface angle (TLS) were compared. 
〖WTHZ〗Results〖HTSS〗At 12 months postoperatively, patients′ AOFAS ankle-hindfoot scores ［(85.49±2.21)points］, step length ［(110.61±2.02)cm］, gait speed ［(100.19±2.05)cm/s］, mean value of foot balance ［(16.22±8.66)N］, range of motion in sagittal plane ［(22.53±1.12)°］, TAS angle ［(90.17±0.76)°］, and TLS angle ［(80.09±0.98)°］ were higher than preoperative values ［(49.68±2.75)points, (71.06±2.87)cm, (76.28±2.01)cm/s, (-36.73±13.98)N, (15.66±1.50)°, (77.87±1.86)°, (76.99±0.63)°］, while VAS scores ［(1.77±0.49) points］ were lower than preoperative scores ［(6.22±0.47) points］, with significant differences (P＜0.001). 
Conclusion Based on the findings of the gait analysis system, SMOT shows good corrective effects and osteotomy healing in varus ankle arthritis, significantly improving ankle function. 

Key words: arthritis, supramalleolar osteotomy； gait analysis