Impact of foot orthoses hindfoot and forefoot wedges on foot and ankle kinematics: A cadaveric study

Introduction Foot orthoses (FOs) are widely prescribed to manage musculoskeletal and inflammatory disorders affecting the lower limbs by modifying foot and ankle biomechanics. While the addition of medial wedges to FOs is believed to enhance control of pronation-related movements, few studies have quantified their isolated kinematic effects under controlled experimental conditions. The use of cadaveric models allows for precise measurement of bone motion without soft tissue artifacts. Therefore, this study aimed to quantify the effects of 3D-printed FOs with and without a medial hindfoot-forefoot wedge on foot and ankle kinematics in cadaveric specimens during quasi-dynamic loading. It was hypothesized that a medial hindfoot-forefoot wedge would better prevent both forefoot dorsiflexion and ankle eversion in cadaveric specimens. Material and methods Nine fresh-frozen lower limbs were tested under three randomized conditions: shoe-only (control), standard FOs (SFO), and medial hindfoot-forefoot wedge FOs (MWFO). FOs were 3D printed in PA11 using the multi-jet fusion technology. Specimens were mounted on a mechanical press with simulated muscle tension applied through tendon loading. Kinematic data were collected via a six-camera motion capture system and reflective markers attached to bone-anchored rods. Ankle and forefoot/hindfoot angles and ranges of motion were calculated in the sagittal, frontal, and transverse planes. Non-parametric Friedman ANOVAs and Wilcoxon signed-rank tests were used to assess between-condition differences (α < 0.05). Results Compared to the control condition, MWFOs significantly reduced peak ankle dorsiflexion (1.40° ± 3.76° vs 3.54° ± 2.74°, p < 0.001) and increased ankle inversion (9.12° ± 11.13° vs 7.09° ± 11.73°, p = 0.002). MWFOs also increased forefoot/hindfoot plantarflexion (p = 0.018) and adduction (p = 0.018) relative to the control condition. No significant differences in joint range of motion were observed across conditions. Conclusions The addition of a hindfoot-forefoot medial wedge to 3D-printed FOs modifies ankle and midfoot kinematics under quasi-dynamic loading, primarily by reducing pronation-related movements such as dorsiflexion and eversion. These findings support the biomechanical rationale for incorporating hindfoot-forefoot medial wedges in FOs design to enhance control of foot and ankle motion.