Abstract:

Objective Investigation into the impact of modified Chevron osteotomy on asymptomatic flatfoot following hallux valgus correction. Methods A retrospective analysis was performed on 118 patients （120 feet） who underwent modified Chevron osteotomy for hallux valgus between January 2018 and December 2022. Based on the Meary angle， the patients were categorized into two groups： an asymptomatic flatfoot group （49 cases， 50 feet） and a non-flatfoot group （69 cases， 70 feet）. Preoperative general data and radiographic parameters were compared between the two groups at baseline and during the last follow-up. These parameters included the talonavicular coverage angle （TNCA）， talus-second metatarsal angle （T2MT） on weight-bearing anteroposterior foot radiographs， and the Meary angle on lateral radiographs. Results There were no significant differences in preoperative general data between the two groups （P > 0.05）. In the asymptomatic flatfoot group， the Meary angle demonstrated a improvement （P < 0.001） when comparing radiographic parameters intra-group between preoperation and the last follow-up. In the non-flatfoot group， TNCA and T2MT increased （P < 0.05）. Inter-group comparisons revealed that preoperatively， TNCA， T2MT， and the Meary angle were significantly worse in the asymptomatic flatfoot group compared to the non-flatfoot group （P < 0.05）. At the last follow-up， there were no significant differences in TNCA and T2MT between the two groups （P > 0.05）； however， the Meary angle remained significantly lower in the asymptomatic flatfoot group than in the non-flatfoot group （P < 0.05）. Conclusions The modified Chevron osteotomy significantly enhances the medial longitudinal arch in patients with hallux valgus and asymptomatic flatfoot， although its effect on correcting abduction is relatively limited. In patients with hallux valgus but without flatfoot， this procedure does not substantially alter the medial longitudinal arch； however， it can induce abduction， which aids in the correction of hallux valgus. This study confirms that the modified Chevron osteotomy effectively improves foot arch structure in asymptomatic flatfoot cases while addressing hallux valgus， without worsening the flatfoot condition.

Key words: osteotomy, hallux valgus, flatfoot, follow-up study