Rotation scarf + Akin osteotomy for severe hallux valgus with a new evaluation index: distance between the first and second metatarsals

BACKGROUND: Although rotation scarf + Akin osteotomy has been described for correcting hallux valgus deformity, the treatment efficacy of rotation scarf + Akin osteotomy for severe hallux valgus should be further studied. The purpose of our study was to evaluate the outcomes of rotation scarf + Akin osteotomy on severe hallux valgus. METHODS: We conducted a retrospective study of patients with hallux valgus who underwent surgery using rotation scarf + Akin osteotomy in our hospital between June 2014 and January 2020. The parameters evaluated include (1) the hallux valgus angle (HVA), (2) intermetatarsal angle (IMA), (3) distal metatarsal articular angle (DMAA), (4) tibial sesamoid position (TSP), (5) the length of first metatarsal bone and (6) ratio between the vertical distance from the lateral of the first metatarsal head to the medial of the second metatarsal head and the vertical distance of lateral of the second metatarsal head to the medial of the third metatarsal head (MT-I to II/II to III distance). A visual analog scale (VAS) was used to evaluate the degree of pain before and at the last follow-up after the operation. The American Orthopaedic Foot & Ankle Society (AOFAS) Forefoot Score wasassessed before and at the last follow-up after the operation. Patient satisfaction assessment was also conducted at the time. RESULTS: All radiological parameters including, HVA, IMA, DMAA and TSP,, significantly improved (p < 0.001). The length of the first metatarsal was shortened 3.1 mm on average. The MT-I to II/II to III distance was also reduced to 1.8 after surgery and 3.3 before surgery. The VAS score and AOFAS score was also statistically significant before operation and at the last follow-up after the operation (p < 0.001). Forty-one (82%) feet in patients were very satisfied or satisfied. CONCLUSION: Rotation scarf + Akin osteotomy is demonstrated to be safe, effective, and feasible for correcting severe hallux valgus. It can obtain good long-term correction with a low incidence of recurrence and metatarsalgia. Postoperative satisfaction and functional recovery of patients are significantly improved. The MT-I to II/II to III distance, a new evaluation indicator, can be better evaluate the correction of hallux valgus.