Fracture-dislocations of the tarsometatarsal joint, a combined anatomical and computed tomographic study.

Based on anatomical and computed tomographic data as well as experience with the treatment of 30 patients with fracture-dislocation of the tarsometatarsal (Lisfranc) joint, a pathophysiological model is described in which the shape of the foot and ligamentous configuration in combination with applied forces are of pivotal importance. CT imaging helps to elucidate the extent of the lesions, easily overlooked in straight radiographs. In the transverse plane we discern three grades of dislocation. Grade 1, virtually no displacement; grade 2, dislocation of half of the shaft; grade 3, total displacement. Treatment is generally dictated by the severity of the lesion and ranges from plaster application to open reduction and internal fixation. Quality of reduction is easily visualized with CT imaging.