Correlation of foot posture index with plantar pressure and radiographic measurements in pediatric flatfoot

Objective: To investigate the correlation between the Foot Posture Index (FPI) (including talar head palpation, curvature at the lateral malleoli, inversion/eversion of the calcaneus, talonavicular bulging, congruence of the medical longitudinal arch, and abduction/adduction of the forefoot on the rare foot), plantar pressure distribution, and pediatric flatfoot radiographic findings. Methods: Nineteen children with flatfoot (age, 9.32±2.67 years) were included as the study group. Eight segments of plantar pressure were measured with the GaitView platform pressure pad and the FPI was measured in children. The four angles were measured on foot radiographs. We analyzed the correlation between the FPI, plantar pressure characteristics, and the radiographic angles in children with flatfoot. Results: The ratio of hallux segment pressure and the second through fifth toe segment pressure was correlated with the FPI (ρ=0.385, p=0.017). The FPI was correlated with the lateral talo-first metatarsal angle (ρ=0.422, p=0.008) and calcaneal pitch (ρ=-0.411, p=0.01). Conclusion: Our results show a correlation between the FPI and plantar pressure. The FPI and pediatric flatfoot radiography are useful tools to evaluate pediatric flatfoot.