Adolescent Flexible Flatfoot: A Cross-Sectional Analysis of Radiographs, Arch Index, and Plantar Pressure

Background: Pediatric flatfoot is a prevalent condition, and its assessment often involves clinical, radiographic, and functional measures. Although symptoms remain central to treatment decisions, radiographic angles, plantar-pressure metrics, and the Arch Index offer quantitative descriptors. Studying their interrelationships is useful to understand how structure and function are linked. This study examined plantar pressure distribution and the relationships among radiographic parameters, Arch Index, and dynamic loading. Methods: This retrospective single-center study included 27 children (51 feet) aged 10-18 years who were diagnosed with flexible flatfoot. Dynamic plantar pressure and contact area were measured, with foot segmentation guided by a foot axis defined as a straight line drawn from the midpoint between the second and third toes to the point of highest pressure in the heel region. Weight-bearing radiographs were used to assess the Meary angle and calcaneal pitch. The Arch Index was derived from dynamic footprints. Correlations among plantar pressure ratios, Arch Index, and radiographic angles were analyzed. Results: Radiographic assessment confirmed flatfoot deformity (mean Meary angle, 20.07°; calcaneal pitch, 11.75°) and an elevated Arch Index. Forefoot loading showed significant anteromedial predominance (medial pressure ≈1.5 × lateral, P < .01), whereas no mediolateral differences were observed in the midfoot or hindfoot. Correlation analysis revealed no significant relationships among the plantar pressure ratio, Arch Index, and radiographic measurements. Conclusion: In adolescent flexible flatfoot, dynamic loading demonstrates anteromedial forefoot predominance. Radiographic angles and dynamic (pedobarography) assessments capture complementary, non-interchangeable aspects of flatfoot. Dynamic analysis may provide additional insight into region-specific loading patterns. Further studies are needed to define its role in clinical decision making. Level of Evidence: Level III, diagnostic, retrospective.