Computed tomography of intraarticular supination - eversion fractures of the ankle in adolescents.

Intraarticular fractures of the ankle in children known as the Tillaux and triplane fractures of the distal tibia are caused by supination-eversion. In order to determine the three-dimensional configuration of these fractures and the relation of the fracture to the growth plate and the joint, computed tomography (CT) was performed in one case with Tillaux fracture and in four cases with triplane fracture, besides conventional radiography and tomography. The Tillaux fracture showed two fragments. The triplane fracture consisted of two to four fragments representing three types of fracture, depending on type of investigation. Conventional radiographs could not differ between two and three fragment triplane fractures, whereas CT offered possibilities to register the epiphyseal and metaphyseal fractures in detail and the exact displacement of the fracture. In one case with a three fragment diagnosed by conventional tomography and CT, a four fragment fracture was revealed at operation. This patient had, in addition, a fracture through the anteromedial part of the growth plate without displacement. According to this and previous investigations, the Tillaux and triplane fractures represent at least five different anatomical pattern of intraarticular supination-eversion injuries.