Flatfoot in children and adolescents. Analysis of imaging findings and therapeutic implications

Introduction: Pes planovalgus (PPV) is a complex three-dimensional deformity of which routine radiographs provide only a two-dimensional analysis. Hypothesis: Angles and other radiographic parameters of the foot in children and adolescents, when studied on both the dorsoplantar and the lateral view, can be used to establish a radiographic classification system for PPV that provides useful therapeutic guidance in clinical practice. Materials and methods: A retrospective single-centre study was conducted on 65 feet in 35 patients aged 7 to 18 years and having adequate ossification. All patients had a clinical diagnosis of idiopathic or neurologic PPV and available weight-bearing dorsoplantar and strict lateral radiographs. We excluded pes planus due to tarsal coalition, congenital bone deformities, or overcorrection of talipes equinovarus (n = 25). All possible axes were drawn and angles measured after an evaluation of interindividual agreement. Results: We identified four patterns of PPV: subtalar pes planus (n = 16) with marked subtalar valgus and longitudinal sag predominating at the talonavicular joint, midtarsal pes planus (n = 12) without subtalar valgus but with marked midtarsal abduction and sag predominating at the cuneonavicular joint, mixed pes planus (n = 28) with subtalar valgus, midtarsal abduction, and sag at both the talonavicular and cuneonavicular joints, and pes planocavus (n = 9) with sag of the medial arch and cavus deformity of the lateral arch. Conclusion: This original classification system provides therapeutic guidance by helping to match the surgical procedure to the nature and location of the deformities. Level of evidence: Level IV. (C) 2012 Elsevier Masson SAS. All rights reserved.