A fifteen-year-old overweight boy sustained a twisting injury of the right ankle. He presented to the emergency department the same day with a deformed ankle and inability to bear weight. The neurovascular examination of the ankle was normal, but there was extensive swelling and tenderness.
Initial radiographs revealed a fracture-subluxation of the ankle mortise with a Salter-Harris type-2 fracture of the distal part of the fibula and a large posterior osseous fragment of unspecified origin (Figs. 1-A, 1-B, and 1-C). The differential diagnosis included a posterior malleolar fracture, a triplane fracture without evidence of the fracture line on the anteroposterior radiograph, and a juvenile Tillaux fracture with unusual posterior displacement.
Immediate closed reduction by internal rotation and eversion was undertaken in the emergency department to reduce the subluxation of the ankle. A computed tomography (CT) scan was obtained to clarify the fracture pattern prior to surgery. This scan clearly demonstrated a juvenile Tillaux fracture with a severely displaced fragment located behind the syndesmosis (Fig. 2). In addition to the fracture of the lateral malleolus, a minimally displaced fracture of the posterior malleolus was also visible. Because of severe local swelling, it was decided to postpone the open reduction and fixation of the fracture. The limb was immobilized in a long leg plaster slab and elevated on a Bohler-Braun frame for six days.
Operative Technique
On the seventh day after injury, an open reduction was performed via an anterolateral approach to the ankle. The capsulotomy did not permit visualization of the epiphyseal fragment until the space in the lateral aspect of the ankle was widened by pulling the distal part of the fractured lateral malleolus laterally with a bone hook, taking care not to disrupt the syndesmosis. This maneuver facilitated the extrication and reduction of the Tillaux fragment, which measured approximately 25 mm × 15 mm × 8 mm and was still partially attached to the anterior tibiofibular ligament. It was stabilized with a 1.2-mm-threaded Kirschner wire, allowing final fixation with a 4.0-mm cannulated screw. The Salter-Harris type-2 fracture of the distal part of the fibula was reduced and fixed with a single retrograde 2.0-mm Kirschner wire. Finally, the anterior tibiofibular ligament, which remained partially attached to both the Tillaux fragment and the lateral malleolus, was sutured to the tibia and fibula with absorbable sutures. At the end of the procedure, the distal syndesmosis was stable and was not fixed with a screw. The postoperative radiographs showed an anatomic reduction of the Tillaux fracture (Figs. 3-A and 3-B). The small posterior malleolus fracture reduced spontaneously and did not receive fixation.
Postoperative Course
The patient remained non-weight-bearing with the ankle in a short leg cast for six weeks. All implants were removed five months after surgery. At the fourteen-month follow-up, the patient had no pain during walking or sporting activities. He had a normal gait with full ankle motion comparable to the left side. The anterior drawer test, talar tilt test, and squeeze test showed no instability or difference between the ankles. Radiographs demonstrated a normal ankle mortise and joint space (Figs. 4-A and 4-B).
The juvenile Tillaux fracture is a distal lateral epiphyseal fracture encountered in children between the ages of twelve and fifteen years. The typical mechanism of injury is inversion of the ankle with external rotation of the foot.
In the classic pattern, the fragment is either undisplaced or minimally laterally displaced and is still attached to the anterior tibiofibular ligament. Usually, the fibula is thought to prevent marked displacement of the fragment. In our patient, we hypothesized that the occurrence of the fibular fracture below the syndesmosis caused a widening of the tibiofibular joint, allowing the Tillaux fragment to displace posteriorly behind the intact syndesmosis. Steinlauf et al. described a case with entrapment of the Tillaux fragment between the tibia and fibula, which simulated syndesmosis separation6. The biomechanical sequence in our case seems identical to that reported by Steinlauf et al. but with additional progression.
We felt that standard radiographs in such an unusual distal tibiofibular fracture in an adolescent would not allow complete delineation of the nature and extent of the injury to facilitate safe surgical planning. Therefore, after initial reduction and cast immobilization, we obtained a CT scan that enabled us to identify the nature of the injury and plan the most appropriate treatment. The need for precise identification of the fracture pattern has been emphasized by Kim et al7.
With our patient, the information provided by the CT scan enabled us to clearly visualize the unique pattern of posterior displacement of the Tillaux fragment and then plan an appropriate surgical approach to reduce and fix both fractures. The anterolateral approach was a rational choice (despite the fact that the fragment was posteriorly located) that permitted satisfactory exposure of the fracture fragments.
The principal limitation of this report is the very short follow-up; a longer follow-up is required to evaluate the long-term ankle function. However, the purpose of this report is primarily to draw attention to a unique injury pattern and to create awareness of the possibility of such an injury when dealing with ankle injuries in adolescents rather than presenting the outcome of our treatment approach.
In conclusion, ankle fractures in adolescents can be complex; this case report emphasizes the need for careful analysis of the mechanism of injury, recognition of the specific injury pattern, and planning the appropriate treatment. We suggest that a preoperative CT scan for any unusual ankle fracture in an adolescent may help to identify the fracture pattern and facilitate surgical planning.
Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. None of the authors, or their institution(s), have had any financial relationship, in the thirty-six months prior to submission of this work, with any entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. Also, no author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.