Normal foot and ankle function was regained by three months.
Discussion
Ankle syndesmosis is formed by distal tibia and fibula and is stabilised with four ligaments - the anterior and posterior tibiofibular ligaments, transverse tibiofibular ligament and interosseous membrane [1].
Sir Astley Cooper, was first to recognize the Tillaux fracture in 1822, as an avulsion injury to antero-lateral distal tibial epiphysis [10]. Tillaux fracture is an eponym given by Paul Jules Tillaux in 1892 who described this avulsion injury and its mechanism of injury following his experiments on cadavers. He described it as an external rotation of ankle that leads to an avulsion fracture of the anterolateral aspect of the tibial plafond owing to the pull of a taut antero-inferior tibiofibular ligament [11]. Chaput later described similar counterpart injury to the posterolateral tibia (avulsion of posterior tibio-fibular ligament), later called Tillaux-Chaput injury.
Distal tibial epiphysis appears at age 6-10 months and it unites with the diaphysis at about age 18 years [1]. Kleiger and Mankin showed that fusion in the distal tibial epiphysis occurs first in the middle third of the epiphysis, followed by, the medial side, and finally in the lateral portion [12]. Tillaux fracture occurs after the medial part of the physis has fused but before the lateral part closes, hence this injury is commoner in adolescents.
In adolescents, the lateral physis is open and anterior tibiofibular ligament is stronger than the epiphyseal bone (growth plate). When a strong external rotational force acts on ankle, it causes a pull force on this strong taut anterior tibiofibular ligament which rather than causing pure ligament rupture, predisposes to an avulsion epiphyseal bony injury leading to an avulsion physeal injury to anterolateral distal tibia. Further since the lateral physis growth plate is avulsed away with fracture line involving the joint, this Tillaux fracture is typically a Salter Harris type III physeal injury [2-4].
In adults this type of injury is very rare because physeal fusion has already been obtained and the ligament strength is less than the bony strength and ligament will usually give way and rupture before avulsion of its attachment to the anterolateral tibial plafond, leading to relative rarity of this avulsion fracture injury pattern in adults.
In adult type of tillaux fracture, the avulsed fracture fragment is triangular as compared to the juvenile one, where the fragment is quadrangular. Adult pattern of Tillaux fractures are classified into Type A and Type B. Type A is avulsion fracture of the antero-lateral aspect of the distal tibial plafond and Type B is a fracture pattern extending into the medial aspect resulting in antero medial pattern [6,7]. A few case reports are published, with this type of fracture in adults, but are not conclusive [4-9].
Like our case, Tillaux fracture is more common with sports related trauma that involves external rotation of the foot in relation to the leg.
Children usually present with inability to bear weight along with painful and tender ankle especially in the anterior part of the ankle, after a low energy trauma, whereas in adults it is usually a high energy trauma and may be associates with other fractures [4-9].
Antero-posterior, lateral and oblique plain radiographs of the ankle are helpful in diagnosing this fracture. But un-displaced fracture or cursory examination of the radiographs can miss the injury, necessitating computed tomography as a useful adjunct to confirm the diagnosis, clearly define the extent of the fracture, rule out any associated injuries involving the tibial pilon and to plan management [13,14].
Acute management includes elevation, ice fomentation and rest. Un-displaced fractures can be managed non-operatively by below knee non-weight bearing cast immobilisation for six weeks. Since these are intra-articular fractures and usually displaced due to avulsion pull by the ligament, these injuries need closed or open reduction with internal fixation to restore ankle joint congruity aiming congruous reduction, rigid fixation, and early mobilization for better functional outcome and to prevent complications like nonunion, malunion, arthritis, deformity and avascular necrosis of the fracture fragment [6,7].
This open reduction can be done by anterior or the anterolateral approach [6]. As per Kumar et al anterolateral approach provides the best access to the fracture [9], but we used anterior approach for fixation and reduction, because we suppose the approach should depend on the extend of the fracture line. Since we have done CT scan, which showed the exact extend of the fracture line, we used the anterior approach for fixation. Careful use of wires as “joysticks” to achieve accurate reduction and fixation, with 1 or 2 inter-fragmental compression screws will usually be enough to stabilize the fractured fragment. Arthroscopy-assisted reduction and percutaneous fixation techniques have also been described to treat this injury, predominantly among adolescents [15].
Conclusion
Tillaux fractures are usually seen in the adolescent population but can, rarely occur in adults. Anatomical reduction and internal fixation leads to a full functional recovery and is recommended in the adult. Fixation is easier in the adult as one does not need to be concerned with iatrogenic physeal injury.
References
1. Rockwood CA, Wilkins KE, King RE. In: Fractures in Children. Vol 3. 3rd edi. Philadelphia, Lippincott Williams & Wilkins, 1996: pp.1341-77 [Crossref][PubMed][Google Scholar]
2. Pesl T, Havranek P. Rare injuries to the distal tibiofibular joint in children. Eur J Pediatr Surg. 2006;16(4):255-9. [Crossref][PubMed][Google Scholar]
