Pathophysiology of juvenile idiopathic arthritis induced pes planovalgus in static and walking condition: a functional view using 3D gait analysis

Background Patients suffering from juvenile idiopathic arthritis (JIA) frequently have affected ankle joints, which can lead to foot deformities such as pes planovalgus (JIA-PPV). Usually, JIA-PPV is diagnosed by examining the foot in non-weightbearing or in weightbearing, static condition. However, functional limitations typically appear during dynamic use in daily activities such as walking. The aim of this study was to quantify the pathophysiology of JIA-PPV in both static and dynamic condition, i.e. in upright standing and during the stance phase of walking using three-dimensional (3d) gait analysis. Methods Eleven JIA patients (age = 12y) with at least one affected ankle joint and fixed pes planovalgus (≥5°) were compared to healthy controls (CG) (n = 14, age = 11y). Kinematic and kinetic data were obtained in barefoot standing and walking condition (1.1–1.3 m/s) with an 8-camera 3d motion analysis system including two force-plates and one pressure distribution plate. All participants were prepared using reflecting markers according to the Oxford Foot and Plug-in-Gait Model. Results were compared using the Mann–Whitney-U-test and Wilcoxon signed-rank test (p