Biomechanical investigation of a custom-made insole to decrease plantar pain of children with flatfoot: A technical note

The abnormal plantar pressure of flatfoot patients is a common condition. The main objective of the present study was to investigate the effect of custom-molded insole on the plantar pain of flatfoot 105 patients (representing 174 feet) participated in evaluating a custom-made orthotic insole from June 2018 to March 2019. The height of the navicular tubercle (HNT) and the deflection angle of calcaneus (DAC) in flatfoot patients after using orthotic insoles for 6 months were recorded by X-ray imaging and scanning measurements. Plantar pressure on metatarsals 1–5 was measured by using an RSscan system Without the use of an orthotic insole, mean HNT was 0.99±0.34 cm and mean DAC was 20.0 ± 3.78 ° during the bearing weight. After using the insole, mean HNT and DAC values reduced to 0.87±0.30 cm and 14.3 ± 3.45 °, respectively (P < 0.05). Hindfoot plantar pressure did not change significantly (P > 0.05). Furthermore, pressure at metatarsals 1–3 decreased by 48.5 %, 45.6 %, and 14.3 %, respectively; that at metatarsals 4–5 increased by 33.3 % and 137.5 %, separately, when using the custom-made insole Visual analog scale score for plantar pain was significantly reduced. These findings indicate that metatarsal pain of flatfoot patients might be the cause of load imbalance in plantar foot.