Influences of Personalized 3D-Printed Insole Orthoses on 3D Ankle Moments during Gait in Individuals with Pronated Hindfoot Deformity

Background Various types of foot orthoses have been used to manage pronated hindfoot deformity (PHD), a common foot deformity. However, few studies have investigated the effects of personalized 3D-printed insole orthoses (3DPIO) for pronated flatfeet on peak ankle moments during gait. Purpose To verify kinetic 3D ankle moments using a reliable motion analysis system with two force platforms among three different foot orthosis conditions. Study design A repeated-measures and cross-sectional study design Methods Kinetic 3D ankle moment data were acquired in twenty-one participants with pronated hindfeet based on three different foot orthosis conditions. A motion analysis system and force flatforms were used to obtain the peak 3D ankle moment data during free walking. The participants performed successful 8 to 10 walking trials for each insole orthosis condition. Results The peak ankle dorsiflexion moment was significantly greater in the 3DPIO condition than in the general shoe insole (GSI) condition (F = 6.208, p = 0.017). The peak ankle plantar flexion moments were significantly greater in the 3DPIO condition than in the GSI and prefabricated insole orthosis (PIO) conditions (F = 9.520, p = 0.004). The first peak eversion moments were significantly greater in GSI walking condition than in the PIO and 3DPIO conditions (F = 12.662, p < 0.001). Additionally, there were no interactive effects between the orthosis conditions and the foot sides in any of the peak ankle moment variables (p > 0.05). Conclusions The results showed that the application of the 3DPIO increased gait efficiency by increasing the ankle dorsiflexion and plantar flexion moments and decreasing first peak eversion moment compared to other orthotic conditions. Therefore, insole orthotic interventions, such as the 3DPIO types, are considered to manage and prevent musculoskeletal problems in individuals with PHD.