Feasibility of Motion Capture-Based Gait Analysis for a Customized Ankle-Foot Orthosis: A Case Report

This study evaluates the feasibility of employing motion capture technology to assess the biomechanical effects of an ankle-foot orthosis (AFO) with a customized varus control strap on lower-limb kinematics and kinetics during gait. While the biomechanical impacts of hindfoot-posted orthoses are well-documented, the influence of varus corrective strapping on proximal joint mechanics remains underexplored. To address this gap, a single-subject pilot study involving a healthy participant was conducted, with kinematic and kinetic data collected across five walking trials under three conditions: barefoot, shod, and shod+AFO. Results demonstrated that the AFO increased double-limb support time from 15% (barefoot) to 20% (shod+AFO) of the gait cycle and reduced peak ankle plantarflexion and dorsiflexion during the swing phase. Ipsilateral knee extension decreased, while heightened variability in joint moments was observed at the contralateral hip and knee. These findings suggest that varus corrective strapping induces sagittal plane kinematic alterations, with compensatory effects extending to the contralateral limb. This pilot study highlights the utility of motion capture systems in evaluating AFO interventions and underscores the need to assess bilateral biomechanical adaptations. Future research should expand to pathological populations, such as individuals with neuromuscular disorders, and investigate frontal plane mechanics to inform AFO customization for clinical populations.