étude cinématique et morphologique en 3dimensions du pied bot varus équin congénital idiopathique

Clubfoot (CF) is a pathology that affects both the morphology and the function and an objective treatment addresses both issues. Yet, to day, few studies combine radiological evaluation and Gait Analysis (GA) in clubfoot children assessment. The aim of this preliminary study was to assess walking age CF patients combining clinical assessment, 3-Dimensional radiographic evaluation and multi-segment foot model gait analysis so as to link results of these methods, and estimate feasibility in a clinical context. Methods We included 10 children with a history of unilateral CF. Feet were classified following the Ghanem and Seringe classification, and a complete physical examination was performed. After placing of the skin markers, a biplanar X-Ray was acquired and the gait analysis recorded. Uncertainty was evaluated through repeatability of placement markers and Monte Carlo error estimation. Finally, 3- Dimensional reconstructions of the feet were performed, and both radiologic and kinematic data were analysed. Findings Concerning radiographic evaluation, all parameters were within the range of reference values for Typically Developing children. Calcaneal Pitch and Tibio Calcaneal Angle were different between affected and non-affected feet. Uncertainty was evaluated as low, which allowed report of kinematic and dynamic data of the joints results. A significant difference of maximum mobility of metatarsal to hallux dorsiflexion during stance and of minimum of ankle dorsiflexion moment was reported. Interpretation To our knowledge, no previous study used the combination of radiological parameters with this Multi-segment Foot Model gait analysis on CF subjects. It appears that despite the very good functional results of the concerned feet, some radiological and motion differences can be detected thanks to this multi segment foot analysis, making this analysis of high interest compared to GA considering the foot as a one rigid-body segment. Therefore this work opens a wide range of following research combining the 3dimensional radiological study and the Rizzoli multi segment foot analysis of the feet of the children. Keywords Clubfeet; children; 3dimensional radiographs; gait analysis; feasibility .

Clubfoot (CF) is a congenital pathology characterized by a triple deformation muscle imbalance3, and the early detection of this abnormality is of interest to achieve the more efficient treatment. Related to the complex structure of the foot, and to the combined abnormalities in CF proper assessment of deformities is crucial to plan the treatment options aiming at a functional and painless foot. So far, assessment of clubfoot relies on observations of generic measurements and clinical allowing for example in toeing of the whole foot but with no further understanding of the structure that is inducing this characteristic. To describe more precisely this inter-segmental motion, a high number of markers was proposed to define the parameters of interest and to create the segments between which the motion is located during walk. In the adult foot, the ideal model should consider the foot as a the most suitable for small and deformed feet, and the most likely to describe internal mobility of the foot. Indeed, this model is reported to have a good reproducibility and considers the foot as a multi segment object, allowing internal radiological evaluation and GA in clubfoot children assessment16, 17,25despite this is the way to link the functional and the anatomical status of CF treatment. However, it has already been suggested that a comprehensive study of walking age CF children combining GA, pedobarography, kinetic, and patient based outcome would be of interest18. GA system and biplanar images and related 3D reconstructions are now easily available for clinicians in health centres. The interest to combine clinical evaluation and these 2 paraclinic ways to evaluate the lower limb and feet has not yet been studied. Therefore, the aim of this preliminary study was to assess in walking age CF patients the matching of kinematic and radiographic 3dimensional data combining clinical assessment, biplanar radiographic images and a Multi-segment Foot Model gait analysis.