Cadaveric evaluation of MIS akin variation on length and angular correction.

Background: Hallux abductovalgus, or bunion deformity, is a common forefoot condition with numerous described techniques for surgical correction. Minimally invasive surgery (MIS) is gaining popularity in the foot and ankle community; however, limited data exists regarding the degree of correction achievable with MIS Akin osteotomies.

Purpose: To compare the angular and length changes produced by oblique and transverse Akin osteotomies using two burr sizes (2.0 and 2.9 mm) in a cadaveric model.

Ethics: The authors state that every effort was made to follow all local and international ethical guidelines and laws that pertain to the use of human cadaveric donors in anatomical research. As a cadaveric study, no IRB review was required.

Study design: Level IV cadaveric study METHODS: Twenty thawed above-knee cadaveric limbs (ten bilateral pairs) were used. Matched pairs underwent either oblique or transverse osteotomies, with the left limbs treated using a 2.0 mm burr and the right limbs with a 2.9 mm burr. Angular correction of the longitudinal axis of the proximal phalanx and medial cortical bone shortening were measured.

Results: The 2.9 mm burr produced significantly greater angular correction and bone shortening than the 2.0 mm burr across all groups (p = 0.002). For oblique osteotomies, the 2.9 mm burr achieved a mean correction of 9.40° versus 4.43° with the 2.9 mm burr (p = 0.037). For transverse osteotomies, angular correction was 14.87° with the 2.9 mm burr compared to 6.64° with the 2.0 mm burr (p = 0.037) CONCLUSION: Burr size and osteotomy orientation significantly affect the degree of correction in MIS Akin osteotomies. These findings support careful preoperative planning and deliberate burr selection to optimize surgical outcomes.