[Comparative study on changes in forefoot width after minimally invasive extra-articular osteotomy via small incision for hallux valgus].

Objective: To compare the difference in forefoot width between minimally invasive extra-articular osteotomy via small incision and traditional Chevron osteotomy in the treatment of hallux valgus.

Methods: A retrospective analysis was conducted on the clinical data of 45 patients with hallux valgus between April 2019 and July 2022. Among them, 22 cases underwent minimally invasive extra-articular osteotomy via small incision (minimally invasive group), and 23 cases underwent traditional Chevron osteotomy (traditional group). There was no significant difference in the baseline data between the two groups ( P>0.05), including gender, age, affected side, Mann classification of hallux valgus, disease duration, and preoperative intermetatarsal angle (IMA), hallux valgus angle (HVA), distal metatarsal articular angle (DMAA), bony forefoot width, soft tissue forefoot width, osteophyte width, and American Orthopaedic Foot and Ankle Society (AOFAS) score. The osteotomy healing time and the occurrence of complications in the two groups were recorded. The differences between pre- and post-operation (changes) in various imaging indicators and AOFAS scores in the two groups were calculated. And the bony forefoot width and soft tissue forefoot width at 1, 6, and 12 months after operation were also recorded and compared between the two groups.

Results: One case of skin injury occurred during operation in the minimally invasive group, while 3 cases of poor wound healing occurred after operation in the traditional group. None of the patients experienced infections, nerve injuries, or other complications. All patients were followed up 12-31 months (mean, 22.5 months). The osteotomy healed in the two groups and no significant difference in healing time between the two groups was found ( P>0.05). The IMA, HVA, DMAA, osteophyte width, and AOFAS score at 12 months after operation significantly improved compared to those before operation ( P<0.05). There was no significant difference between the two groups in the changes of IMA, HVA, and osteophyte width ( P>0.05). However, the differences in the changes of AOFAS score and DMAA were significant ( P<0.05). There was no significant difference between the two groups in bony and soft tissue forefoot widths at different time points after operation ( P>0.05). However, there were significant differences in the two groups between the pre- and post-operation ( P<0.05).

Conclusion: The minimally invasive extra-articular osteotomy via small incision for hallux valgus, despite not removing the medial osteophyte of the first metatarsal, can still effectively improve the forefoot width and osteophyte width. While correcting the IMA and HVA, it can more effectively restore the DMAA, resulting in better AOFAS scores.