Comparison of Open Scarf-Akin Osteotomy and Minimally Invasive Chevron and Akin (MICA) Osteotomy for Severe Hallux Valgus Deformity: A Retrospective Study

Background: Minimally invasive surgery (MIS) for hallux valgus, particularly the minimally invasive chevron and Akin (MICA) technique, is gaining popularity. However, comparative studies between open scarf-Akin osteotomy (SA) and MICA remain limited, particularly for severe cases (ie, hallux valgus angle HVA ≥ 40° or intermetatarsal angle IMA ≥ 16°). This study aimed to compare the clinical and radiographic outcomes between SA and MICA for severe hallux valgus. Methods: We retrospectively reviewed 56 consecutive feet (SA = 33; MICA = 23) treated between January 2019 and January 2023 at a single institution in Hong Kong. Clinical outcomes were evaluated using the American Orthopaedic Foot P = .003) and shorter length of stay (beta = −2.35 days, 95% CI −3.52 to −1.17; P < .001). After this adjustment, AOFAS improvement was greater in MICA (beta = +6.40, P = .008), whereas SEFAS and VAS improvements were not statistically different. For pronation, SA achieved superior apparent correction: severe postoperative pronation (Wagner 3) was 0% after SA vs 48% after MICA, and baseline-adjusted ordered logistic regression similarly favored SA (MICA vs SA OR 3.75, 95% CI 1.08-13.03; P = .037). Conclusion: Both procedures reliably corrected severe HV deformity. MICA was associated with shorter total operative time and reduced length of stay. In exploratory covariate-adjusted sensitivity models, MICA maintained advantages in operative time and AOFAS scores, whereas between-group differences in SEFAS and angular radiographic outcomes were attenuated or nonsignificant. In contrast, SA demonstrated stronger correction of apparent first-metatarsal pronation, with no apparent residual severe pronation at follow-up compared with MICA. Level of Evidence: Level III, retrospective cohort study.