IMPACT OF WEIGHTBEARING ON FOOT SHAPE: A GEOMETRIC AND MORPHOMETRIC ANALYSIS

As WBCT has only recently been introduced in clinical settings, its full potential in elucidating the impact on the complex 3D geometry of the foot, both in healthy and pathological states, remains under-explored. Until now, studies analysing foot morphology have largely relied on discrete evaluations, resulting in a somewhat fragmented understanding of the foot's structural complexity upon weightbearing. Therefore, the objective of this study was to investigate and delineate the differences in foot morphology between weight-bearing (WB) and non-weight-bearing (NWB) conditions by Geometric morphometric methods. A matched-control study design was implemented. Initially, 82 feet from 41 subjects were scanned using MRI, with the subjects in supine position. Subsequently, matched cases were retrospectively selected from a cohort of patients who undergoing WBCT imaging for clinical follow-up of disorders unrelated to the foot. Principal polynomial shape analysis was then applied to the reconstructed foot models to identify significant variations in three-dimensional foot shape between the two groups. Result: Principal polynomial shape analysis revealed foot morphology components. In the WB foot group, the first three principal components explained 56.4% of variance. For the NWB group, the initial three principal components accounted for 59% of variance. Significant differences were found in the mean foot shape between the two groups. The findings validate the 3D spatial position alterations in WB foot compare the NWB foot. These include an increased hindfoot valgus, a decreased height of the longitudinal arch and increased width of the forefoot.