Flexible flatfoot: differences in the relative alignment of each segment of the foot between symptomatic and asymptomatic patients.

Abstract

Flexible flatfoot is a physiological variation of normality that does not need correction unless it becomes symptomatic. It remains unclear why some flexible flatfeet become symptomatic. Operations for symptomatic flatfoot correct the theoretical deformities with the intent of relieving symptoms. Using radiographic measurements, we analyzed the relative alignment of each segment of the foot in symptomatic and asymptomatic flexible flatfoot. One hundred and thirty-five patients with idiopathic flexible flatfoot were identified restrospectively and divided into 3 groups: (a) 45 asymptomatic; (b) 45 symptomatic with conservative treatment; and (c) 45 symptomatic with surgical treatment. Standing anteroposterior and lateral radiographs of the foot were analyzed. Thirteen measurements were calculated to describe the alignment of the hindfoot, midfoot, and forefoot. Multivariate analysis of variance and Bonferroni post hoc comparisons were used for statistical analysis. Age and sex were similar in the 3 groups. Significant differences among the 3 groups were found in 8 measures. However, differences between asymptomatic (a) and symptomatic (b) flatfeet were found in just 2 measures: talonavicular coverage, with a large effect size (0.59); and lateral calcaneo-fifth metatarsal angle, with a small effect size (0.10). There were no differences, between symptomatic (a) and asymptomatic (b) flexible flatfeet, in the measures that describe the alignment of the hindfoot, the longitudinal arch, the lateral column length or the pronation/supination of the forefoot. However, the lateral displacement of the navicular, measured by the anteroposterior talonavicular coverage, seems to be related to the onset of symptoms among patients with flexible flatfeet.