Injury mechanism and clinical presentation of triplane fracture of the distal tibia in adolescence

Objective To study the clinical presentation and injury mechanism in triplane fracture of the distal tibia in adolescence.Methods A retrospective clinical and radiological study was carried out on 17 patients presented with acute triplane fractures of the distal tibia. The position of the ankle and foot at the time of injury was reviewed. The detailed configuration and displacement of the distal fragment was documented by 3-D CT.Results The frequencies of occurrence of the lateral type, two-part type and type I were 100%, 88.2% and 70.6% respectively. The injury occurred with the foot and ankle in varus and plantaflexion positions were 82.3% and 47.1% respectively. From the 3D CT analysis, the displacement of the distal fragment in external rotation, varus and plantiflextion were found to occur in 100%, 50% and 71.4% respectively.Conclusions Lateral type, 2-part type and typeⅠwere the most common types in triplane fracture of the distal tibia. Excessive varus, plantaflexion and external rotation of the ankle may probably be the main factors leading to the triplane fracture. The understanding of the pathology-anatomy could help the 'triplane reduction' of the fracture.