Flatfoot as a late sequela of subtle injuries to the Lisfranc joint

In this retrospective study, 13 patients with subtle Lisfranc joint injuries were examined after a mean period of 23 months using clinical assessment, radiography and dynamic pedographic gait analysis. The aims were to identify the factors leading to a mobile flatfoot deformity, evaluate the functional and clinical outcome of these injuries, and draw practical conclusions for initial management and subsequent intervention. All patients showed a mobile flatfoot deformity, increased motion in the subtalar joint, increased load on the hindfoot, decreased load on the forefoot, and a prolonged contact phase during the stance phase. Radiographs revealed progressive osteoarthrosis in the joint and a residual displacement of the medial Lisfranc joint. An unstable medial Lisfranc joint results in the development of a mobile flatfoot. Initial treatment of a subtly displaced Lisfranc joint should consist of exact anatomical reduction and additional maintenance of the longitudinal arch of the foot. After failed initial treatment, early arthrodesis of the midfoot is recommended as a salvage procedure for the foot.