Review Question - QID 217345

This patient has sustained a Tillaux fracture, a type of transitional ankle fracture. Avulsion of the insertion of the anterior inferior tibiofibular ligament is implicated in the pathogenesis of this injury (Answer 3).

Tillaux fractures represent a Salter-Harris III fracture of the anterolateral distal tibia epiphysis. A type of transitional fracture, these injuries occur when an external rotation force is imparted upon a supinated foot. In the setting of incomplete physeal closure, this force leads to avulsion of the anterolateral tibia at the site of attachment of the anterior inferior tibiofibular ligament (AITFL). Due to the fact that the distal tibia physis closes from central to anteromedial to posteromedial to lateral, it follows that the anterolateral tibia represents an area at risk for injury in patients nearing skeletal maturity. Tillaux fractures are differentiated from triplane fractures, another type of distal tibia transitional fractures, in two ways. First, the fracture is completely epiphyseal, and second, patients with Tillaux fractures are typically closer to skeletal maturity than patients who sustain triplane fractures.

Johnson and Fahl provided one of the earliest reviews of transitional ankle fractures. They reported on 27 children between 8 and 16 years of age. They noted that due to the variable amount of physeal closure present in patients nearing adolescence, injuries to the ankle produced predictable fracture patterns. Patients with minimally displaced fractures were treated with immobilization, while those with displaced fractures underwent open reduction and internal screw fixation.

Duchesneau and Fallat authored an early review and report on two cases of Tillaux fractures. They note that secondary to a predictable pattern of physeal closure, the insertion site for the AITFL is at risk when an external rotation force is imparted through a supinated forefoot. They postulate that fractures with less than 2 mm displacement following closed reduction can be treated with cast immobilization, while displaced fractures require open reduction and internal fixation.

Wuerz and Gurd provide a comprehensive review of pediatric physeal ankle fractures, which typically occur during the 18 months preceding physeal closure. They note that Tillaux fractures account for 3-5% of all pediatric ankle injuries, and occur secondary to the avulsion of the tibia insertion of the AITFL. They propose that fractures with less than 2 mm displacement can be treated non-operatively, while those with greater than 2 mm of residual displacement following closed reduction should undergo open-reduction with internal fixation.

Figure A demonstrates an AP and lateral ankle radiograph of a skeletally immature individual with a Salter-Harris III fracture to the anterolateral tibial plafond consistent with a Tillaux Fracture. Figure B represents a labeled diagram of the ankle ligaments.

Incorrect Answers
Answer 1: this represents the posterior inferior tibiofibular ligament (PITFL)
Answer 2: this represents the posterior talofibular ligament (PTFL)
Answer 4: this represents the anterior talofibular ligament (ATFL)
Answer 5: this represents the calcaneofibular ligament (CFL)