Effect of Custom-Made Orthotic Insoles on Lower Limb Biomechanics in Children with Flexible Flat Feet

This study aimed to investigate the effect of custom-made orthotic insoles on the lower limb biomechanics in children with flexible flat feet. A sample of 27 children (19 boys and eight girls) aged 7 to 13 years old with flexible flat feet participated in the study. Each custom-made orthotic insole was individually designed based on the foot of each subject, using ethylene-vinyl acetate (EVA) material with medium density. The study was conducted using a gait analysis laboratory, and participants were required to walk randomly at a self-selected speed with one of three insole conditions (custom-made orthotic insole, flat insole, and barefoot). The data was processed using Visual 3D software and analyzed by SPSS software. The results showed that using custom-made orthotic insoles resulted in a significant reduction in the maximum ankle inversion angle and ankle inversion moment while increasing the knee adduction moment during the stance phase when compared to wearing either flat insoles or being barefoot (p<0.05). This study found that custom-made orthotic insoles significantly altered the biomechanical characteristics of the lower limbs of children with flexible flat feet, reducing the movement of the ankle joint in the frontal plane, thereby enhancing ankle joint stability, but may increase knee joint load.