Review Question - QID 218716

This patient has sustained a Tillaux fracture, shown in the radiograph in Figure A. The characteristic fracture pattern is due to an avulsion involving the anterior inferior tibiofibular ligament (AITFL), which is one component of the ankle syndesmosis. Injury to the syndesmosis is also described in high ankle sprains.

Transitional fractures of the pediatric ankle are characterized by involvement of the physis and include triplane and Tillaux fractures. Both fractures typically result from an external rotation mechanism, where the comparatively stronger AITFL produces an avulsion fracture off of the anterolateral aspect of the distal tibia (Chaput tubercle). Depending on the fusion status of the distal tibia physis, this mechanism may produce a Salter-Harris III (Tillaux) or IV (triplane) fracture pattern. Adolescents near skeletal maturity with a partially fused physis tend to sustain Tillaux fractures, whereas younger children (age ~10-12) in whom the physis has not yet begun to fuse tend to sustain triplane fractures.

The ankle syndesmosis is comprised of the anterior and posterior inferior tibiofibular ligaments (AITFL and PITFL, respectively), and confers stability of the distal tibiofibular joint. An intact syndesmosis is crucial to maintaining the stability of not just the tibiofibular articulation but also the tibiotalar articulation as well, since an intact syndesmosis prevents lateral translation of the fibula and maintains a congruent ankle joint. Syndesmotic injuries, commonly seen in high ankle sprains and ankle fractures, must be anatomically reduced to maintain ankle joint congruity and minimize the risk of post-traumatic ankle arthritis. Similarly, treatment aims in pediatric transitional ankle fractures are anatomic reduction and a minimal residual gap at the articular surface.

Zelenty et al. performed a 2018 retrospective cohort study comparing open reduction versus percutaneous fixation of adolescent ankle fractures with regard to the incidence of growth disturbance. Acknowledging that their study was underpowered due to the rarity of these fractures, the authors reported no instances of growth disturbance in the percutaneous fixation group and six in the open reduction group, although this was not statistically significant. Of greater importance, however, the authors state that an open reduction technique exhibited a trend toward a significantly higher rate of postoperative pain, resulting in higher rates of hardware removal.

Lurie et al. published a 2020 retrospective review of transitional fractures to determine whether operative treatment of transitional fractures with 2 to 5 mm of intra-articular gap leads to superior functional outcomes compared with cast management. Patients with Tillaux or triplane fractures were assessed for degree of post-reduction residual gapping on CT, operative versus nonoperative treatment, and functional outcomes scores over a mean period of 4.5 years. Gapping at the tibial plafond of 2-5mm, a greater gap after closed reduction, nonoperative treatment, and complications were negative predictors of functional outcome. The authors concluded that surgical management likely conveys the greatest functional benefit when the intra-articular gap exceeds 2.5 mm.

Figure A is an AP radiograph of a skeletally immature ankle demonstrating a Tillaux fracture. Illustrations A and B are oblique and lateral postoperative radiographs following screw fixation. Illustration C is a depiction of a Gosselin fracture.

Incorrect Answers:
Answer 1: A Gosselin fracture is a V-shaped fracture of the distal tibia which extends into the ankle, fracturing the tibial plafond into anterior and posterior fragments.
Answer 2: A subtalar dislocation does not classically involve the syndesmosis.
Answer 3: Weber A ankle fractures are described as occurring below the level of the syndesmosis, thereby not involving the syndesmotic ligaments.
Answer 5: A low ankle sprain is characterized as involving the anterior talofibular ligament (ATFL), not the AITFL.