The role of the foot ligaments in the formation of complex calcaneal fractures

Background. Established knowledge on the mechanisms of various types of calcaneal fractures necessitates further investigation to elucidate the role of ligaments in the formation of constant fracture types and the development of characteristic bone fragments. The purpose is to analyze the specific influence of the ligaments of the rearfoot on the formation of complex calcaneal fractures. Materials and methods. A total of 53 scientific publications from the Scopus, Web of Science, and PubMed databases were reviewed. To examine the insertion sites, an analysis of 14 anatomical specimens of calcaneal bone from the anatomical museum of the Poltava State Medical University was conducted. A Schweizer Tech-Line 4X magnifying optical device was used. To form interactive 3D models and reconstruct the studied structures and typical fracture lines on their surface, we used a licensed version of the Microsoft Paint 3D. Results. The analysis of interactive 3D models demonstrates a clear distribution of ligament attachment sites around the constant fragments, revealing a direct correlation between the number and area of ligamentous insertions and the stability of the bony fragment. According to the literature, the most stable fragment is the medial (sustentacular) one, which serves as the attachment site for several ligaments in multiple planes. A similar relationship was observed for both anterior fragments. As a result, the energy applied by a traumatic agent, when distributed across the calcaneal bone, is often insufficient to overcome the resistance of these strong ligamentous structures. Moreover, the energy is concentrated in corresponding areas of the bone, leading to the formation of primary and secondary fracture lines. This finding explains why the lateral portion of the posterior calcaneal articular facet undergoes significant displacement, as no ligamentous insertions were identified in this region. Conclusions. By examining the insertion sites of the ligaments of the rearfoot on the calcaneal surface and correlating these findings with typical fracture lines and fragment formation, it can be concluded that ligamentous structures may significantly influence the development of complex calcaneal fractures. This observation warrants further biomechanical research and may contribute to refining the existing paradigms of surgical and rehabilitative management for complex calcaneal fractures.