Journal of the American Academy of Orthopaedic Surgeons December 2007, Volume 15, Issue 12 The Pediatric Triplane Ankle Fracture Copyright © 2007 by the American Academy of Orthopaedic Surgeons. Kent A. Schnetzler, MD, MS and Daniel Hoernschemeyer, MD Dr. Schnetzler is Orthopaedic Surgeon, Woodland Park Orthopaedic Associates, Pikes Peak Regional Hospital, Woodland Park, CO. Dr. Hoernschemeyer is Assistant Professor of Pediatric Orthopaedic Surgery, Department of Orthopaedic Surgery, University of Missouri-Columbia, Columbia, MO. None of the following authors or the departments with which they are affiliated has received anything of value from or owns stock in a commercial company or institution related directly or indirectly to the subject of this article: Dr. Schnetzler and Dr. Hoernschemeyer. Reprint requests: Dr. Hoernschemeyer, Department of Orthopaedic Surgery, University of Missouri-Columbia, MC213, 2nd Floor McHaney Hall, One Hospital Drive, Columbia, MO 65212. The pediatric triplane ankle fracture represents a unique spectrum of injury that does not fit neatly into the Salter-Harris classification of physeal injury. This fracture is particular to the pediatric population and often is termed a transitional injury. It is the result of the characteristic asymmetric closure of the distal tibial physis over a period of approximately 18 months. The triplane ankle fracture is a multiplanar injury with three classically described fracture fragments. It has several variations and represents 5% to 10% of pediatric intra-articular ankle injuries. The fracture typically presents in children aged 12 to 15 years; incidence is slightly higher in boys than in girls. Nondisplaced triplane fractures and extra-articular fractures can be managed with immobilization in a long leg cast. Displaced fractures are treated with open reduction and internal fixation performed through an anterolateral approach or an anteromedial approach. Intra-articular reduction to within 2 mm is required for optimal treatment of these unique pediatric ankle fractures.