Minimally invasive hallux valgus correction with Internal Hallux Fixator® - A comparative cadaver study

Background: The Internal Hallux Fixator (R) (IHF (R); Waldemar Link, Hamburg, Germany) was designed for open surgical hallux valgus correction. It allows a defined lateralisation of the first metatarsal head after V-shaped, Chevron-like distal metatarsal osteotomy in order to correct mild to middle hallux valgus deformities. The intramedullary fixation provides dynamic compression of the osteotomy and thus postoperative full weight bearing mobilization is an integral part of the therapy. This comparative cadaver model study investigates the feasibility of implanting the device using a minimally invasive technique and compares its capability of first metatarsal head lateralisation to the established 3rd generation MICA (Minimally Invasive Chevron and Akin osteotomy) technique. Methods: 16 fresh frozen cadaveric feet (8 left, 8 right) of 8 body donors received either MICA (Group 1), or an IHF (R) in a minimally invasive technique (Group 2). The achievable first metatarsal head lateralisation and operating time were measured and pitfalls recorded. Results: This cadaver model study confirmed, the minimally invasive implantation of the Internal Hallux Fixator (R) can be performed reliably via 10 mm mini incision with V-shaped distal metatarsal osteotomy. The mean first metatarsal head lateralisation was comparable between the groups with no statistically significant difference (7.2 (+/- 1.9) mm in G1, or 8.3 (+/- 0.8) mm in G2; p = 0.09). The IHF (R) was inserted and fixed in mean 3.7 (+/- 0.6) min, whereas double screw fixation needed 10 (+/- 3.7) min. (C) 2021 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.