Geometric Assessment and Tissue Damage Control in Anatomically, Ultrasonographically, and Fluoroscopically Guided...

Introduction: Distal intracapsular minimally invasive osteotomies (DICMOs) for central metatarsals are described as intracapsular procedures; however, neither their intracapsular location throughout the entire cut nor the optimal anatomical position for their execution have been fully validated. The aim of this study was to assess the geometric position of the DICMO osteotomy in the central metatarsals (third and fourth) and quantify associated anatomical damage when performed under three different guidance modalities: anatomical palpation, fluoroscopic control, and ultrasound guidance. Material and methods: An experimental cadaveric study was conducted using 29 fresh specimens (11 males, 18 females), contributing a total of 58 central metatarsals (third and fourth). All specimens underwent a DICMO-type metatarsal osteotomy. Osteotomies were randomly allocated to three intervention groups: (1) ultrasound (n = 20), (2) fluoroscopy (n = 19), and (3) anatomical guidance (n = 19). Metatarsal length, the distance between the osteotomy line and the articular surface, and post-dissection soft-tissue damage were recorded. Results: After dissection, all osteotomies were confirmed to be intracapsular. A constant proportional relationship was identified between osteotomy location and metatarsal length: distance to the joint line = 0.239 × metatarsal length. This relationship was independent of the guidance technique used. Only one iatrogenic lesion was observed: an articular cartilage injury of a third metatarsal in the anatomical-guidance group. Conclusions: The optimal position for DICMO osteotomy placement is approximately 24% of the total distal metatarsal length. This ensures an intracapsular trajectory and may contribute to intrinsic osteotomy stability. Image guidance-either fluoroscopy or ultrasound-appears essential to optimize outcomes and prevent avoidable anatomical damage.