Anatomic safety profile of a novel mini external fixator for proximal crescentic osteotomy in hallux valgus correction: a cadaveric study

Abstract

Purpose The proximal crescentic osteotomy is an effective procedure for hallux valgus correction, but stable fixation remains challenging. Our previous biomechanical study suggested that the MEF may offer comparable or greater stability than a specific cannulated screw fixation construct in a cadaveric model. This study aims to evaluate the anatomical safety of the MEF by investigating its relationship with critical neurovascular structures and tendons. Methods An anatomical dissection study was performed on ten foot cadaveric specimens. The MEF was applied using five mini-Schanz pins inserted in predefined positions. Following fixation, a layer-by-layer dissection was conducted to expose the dorsalis pedis artery, superficial cutanous branches of the foot, the superficial venous arch, and the extensor hallucis longus and brevis tendons. The distance from each pin to these structures and any iatrogenic injuries were recorded. Results The superficial venous arch was injured at low rates by the medial distal pin (20%), the medial proximal pin (10%), and the lateral distal pin (20%). Tendon injury was more frequent, with the extensor hallucis longus tendon being injured by 20-30% of pins, and the extensor hallucis brevis tendon by the lateral intermediate and distal pins (20% each). Conclusion The application of the MEF for first metatarsal fixation appears anatomically safe with respect to major arteries and nerves. The consistent avoidance of the dorsalis pedis artery and key sensory nerves is a significant advantage over some established techniques. However, surgeons should be aware of the potential risk to the superficial venous arch and extensor tendons during pin placement. These findings support further investigation of the MEF for proximal crescentic osteotomy fixation.