The effect of insoles on symptomatic flatfoot in preschool-aged children: A prospective 1-year follow-up study

Flatfoot is a common reason for parents to seek help from health care professionals, and limited evidence is available regarding the effects of insoles on preschool-aged children. This study mainly investigated the effect of insoles on symptomatic flatfoot in preschool-aged children and followed up the changes in footprints after 1 year. This study was a prospective, observational cohort study. Children aged 3 to 5 years old who exhibit the signs of flatfoot feet were recruited from the kindergartens in the central Taiwan between March 2010 and December 2013. The Chippaux-Smirak index (CSI) was used to determine whether the footprints of children were associated with flatfoot. The children were divided into an insole group and a no-insole group according to diagnoses by doctors. This study used the modified shoe insole as the intervention, and the CSI measured and followed up the changes in footprints after 1 year. A total of 466 preschool-aged children aged 3 to 5 years old with flatfoot completed the 1-year follow-up study. Of these, 123 children (men 77; women 46) were in the insole group and 343 children (men 187; women 156) were in the no-insole group. After the insoles were worn for 1 year, the CSI values of the children with symptomatic flatfoot decreased by 9.7%, and the 5-year-old children had the biggest change (effect size = 1.25). In the insole group, 34.1% of the footprints were determined as normal at 1-year follow-up, and CSI values decreased by 17.5%. High prevalence of joint laxity was found in both groups (insole group: 34.5%; no-insole group: 35.1%). Of the children in the insole group, the proportion of joint laxity was significantly higher in the flatfoot group (43.1%) than in the normal group (17.7%). This study showed that wearing insoles indeed can reduce the signs of flatfoot in preschool-aged children, and the effect is better in 5-year-old children. It is suggested that insoles can be provided as a conservative treatment for preschool-aged children with symptomatic flatfoot.