Is a keystone Bone Anomaly the Main Cause of Flatfoot (Pes Planus)?

Background: Flatfoot (pes planus) is a decrease or loss of longitudinal medial arch height. The cause of symptomatic flatfoot occurring in adolescents is still unclear. In this study, the relationship between adolescent pes planus and foot bone shape was investigated. For this purpose, the volume and superficial area data of the foot bones of adolescent individuals with flatfoot deformity and individuals without any foot deformity were compared.

Methods: Between September 2022 and June 2023, 30 individuals with adolescent pes planus with a medial arch angle greater than 145 degrees and 30 individuals without any foot deformity were included in the study. Computed tomography (CT) images of the participants' feet were obtained with a General Electric brand IQ model 32 detector CT device with a section thickness of 0.625 mm in accordance with the bone protocol. Using the 3D Slicer program on CT images, foot bones were segmented and the volume and surface area ratios of each foot bone were determined.

Results: Cuneiforme mediale and cuneiforme intermediale volume ratios in individuals with flatfoot deformity decreased by 14% and 24%, respectively, compared with the control group ( P <0.05). Cuneiforme mediale and cuneiforme intermediale superficial area ratios were found to be 10% and 30% lower in the flatfoot group compared with the control group, respectively ( P <0.05). There was no difference in the volume and superficial area ratios of other foot bones between the groups ( P >0.05).

Conclusions: The study results suggest that symptomatic adolescent flatfoot deformity may be associated with developmental anomalies of the os cuneiforme mediale and os cuneiforme intermedium.