NOVEL BIOMECHANICAL MEASUREMENTS FOR 3D CHARACTERIZATION OF THE FOOT IN WEIGHT-BEARING

The biomechanics of the human foot is fundamental for understanding normal gait and assessing pathologies. Medical images, obtained through traditional two-dimensional (2D) techniques or even standard three-dimensional (3D) scans in supine, cannot capture the structural changes occurring in weight-bearing conditions. On the other hand, weight-bearing computed tomography (WBCT) allows for 3D models of bones with the advantage of being under loading conditions, thus overcoming the limitations of the above techniques. For these reasons, this study utilised WBCT to analyse foot biomechanics in loading and unloading conditions. 3D bone models were reconstructed from three cadaveric feet. Volume changes were assessed in specific plantar regions, such as the rearfoot, midfoot, forefoot, and beneath the metatarsals. Joint coverage was analysed for the subtalar, talonavicular, and calcaneocuboid joints. Moving from unloaded to loaded condition, results showed considerable reductions in the total foot volume (5.27% with respect to the unloaded condition), especially underneath the rearfoot (9.24%). As for the corresponding variations in terms of joint coverage, the subtalar joint exhibited a considerable reduction in the anterior facet (11.16%), while in the calcaneo-cuboid joint it increased by 4.63%. These findings highlight the advantages of WBCT and 3D analysis by providing a detailed, region-specific understanding of foot biomechanics, specifically the changes in the volumes of the plantar arches in different loading conditions, overcoming the limitations of traditional methods. This study demonstrates the feasibility and potential of advanced 3D imaging techniques for comprehensive foot analyses. In the future, this approach could be valuable for interpreting clinical outcomes in the surgical correction of flat foot, as well as the evolution of foot biomechanics in diabetic subjects, which would help determine the efficacy of the adopted treatments and possibly improve them.