Radiologic assessment of Minimally Invasive Chevron and Akin (MICA) procedure for the correction of moderate and severe hallux valgus

J. Gaskin, M. Gajewar, T. Hardwicke, N. Hossain, J. Vernois

Introduction: Chevron osteotomies are traditionally used only for correction of mild hallux valgus, other osteotomies being employed for moderate deformities (eg. scarf osteotomies) and severe deformities (eg. basal osteotomies). MICA, a percutaneous distal chevron osteotomy of the 1^st metatarsal is being used for the correction of moderate and severe hallux valgus deformities in our unit. We aim to demonstrate the radiographic improvements in the Hallux Valgus Angle (HVA) and Inter-Metatarsal Angle (IMA) when using MICA in the treatment of moderate and severe Hallux valgus.

Methods: Measurement of the HVA and IMA of pre and post-operative radiographs from MICA procedures done over 2 years by a single surgeon was done by 2 authors using PACS software. We defined a moderate deformity as an IMA greater than 13° (14-20°) or an HVA of less than 40° (16-40°) and a severe deformity as an IMA of greater than 20° or an HVA greater than 40°.

Results: There were 142 MICA procedures. 38 were bilateral. Majority were female. Age range 26 - 80. Pre-op HVA was moderate in 114 (30.3°, range 16-40°) and severe in 28 (47.0°, range 41-70.7°). Of these, IMA was moderate in 62 (16°, range 14-20°) and severe in 1 (22.2°). The mean post-operative HVA was 9.5° (range 0-23°) for the correction of moderate hallux valgus and 15.5° (1-35°) for severe hallux valgus. The mean post-operative IMA for the correction of moderate hallux valgus was 6.9° (3-13°). Complete radiographic union appeared to have occurred in all cases 12 weeks post-operatively.

Conclusion: This study demonstrates that the MICA procedure involving a distal osteotomy can be successful in correcting the HVA and IMA in moderate and severe hallux valgus deformities.