The effect of prefabricated and proprioceptive foot orthoses on plantar pressure distribution in patients with flexible flatfoot during walking

Background: Previous studies have suggested that orthoses with different constructions could alter gait parameters in flexible flatfoot. However, there is less evidence about the effect of insoles with proprioceptive mechanism on plantar pressure distribution in flatfoot. Objectives: To assess the effect of orthoses with different mechanisms on plantar pressure distribution in subjects with flexible flatfoot. Study Design: Quasi-experimental. Methods: In total, 12 flatfoot subjects were recruited for this study. In-shoe plantar pressure in walking was measured by Pedar-X system under three conditions including wearing the shoe only, wearing the shoe with a proprioceptive insole, and wearing the shoe with a prefabricated foot insole. Results: Using the proprioceptive insoles, maximum force was significantly reduced in medial midfoot, and plantar pressure was significantly increased in the second and third rays (0.94 +/- 0.77 N/kg, 102.04 +/- 28.23 kPa) compared to the shoe only condition (1.12 +/- 0.88 N/kg and 109.79 +/- 29.75 kPa). For the prefabricated insole, maximum force was significantly higher in midfoot area compared to the other conditions (p < 0.05). Conclusions: Construction of orthoses could have an effect on plantar pressure distribution in flatfeet. It might be considered that insoles with sensory stimulation alters sensory feedback of plantar surface of foot and may lead to change in plantar pressure in the flexible flatfoot.