Adolescent Distal Tibial Tillaux & Triplane Fractures: Pathophysiology, Diagnosis, and Management
Key Takeaway
Tillaux and Triplane fractures are unique intra-articular distal tibia injuries in adolescents. Tillaux (Salter-Harris III) is an epiphyseal avulsion. Triplane (Salter-Harris IV) is a complex multi-planar injury involving epiphysis, physis, and metaphysis. Their occurrence depends on specific physeal closure stages, demanding precise reduction to prevent complications.
A 13-year-old girl presents following an inversion injury to her ankle while playing netball. She is unable to weight-bear. Plain radiographs are suspicious for a distal tibial epiphyseal injury. What is your next priority in investigation, and what are the specific clinical implications of this injury pattern regarding the patient's age?
Candidate: I would immediately order a CT scan of the ankle. Given her age (13), she is in the window of physeal closure, making her susceptible to transitional fractures like Tillaux or Triplane fractures. The CT is essential to determine the extent of articular involvement and the number of fragments for surgical planning.
Failing to mention the specific mechanism of closure of the distal tibial physis (central to medial to lateral). Candidates often treat the CT request as a generic necessity without explaining why—specifically, that the lateral physis remains open while the medial has fused, creating the biomechanical vulnerability for these specific fracture patterns.
The immediate priority is a thin-cut CT scan with 3D reconstructions. Anatomical reduction is mandatory for intra-articular injuries in this age group to prevent post-traumatic arthritis. I would frame this by explaining the distal tibial physis closure sequence: central, then medial, leaving the lateral portion last to fuse. This makes the adolescent vulnerable to external rotation forces that cause the AITFL to avulse the lateral epiphysis (Tillaux) or create the complex multi-planar Triplane fracture. The CT is the "Gold Standard" to identify fragment count (2, 3, or 4-part) and quantify the articular step-off (threshold of 2mm) to dictate operative intervention.
You are in the operating theatre. You have achieved an anatomical reduction of the anterolateral epiphyseal fragment for a Triplane fracture. However, the posterior metaphyseal component remains displaced by 3mm. How do you proceed surgically?
Candidate: I would first attempt a closed reduction maneuver, such as internal rotation of the foot with axial compression. If this fails to reduce the posterior fragment to within 2mm, I would perform a posterior approach—likely posteromedial—to visualize the fragment and directly reduce it, using K-wires for joystick manipulation before internal fixation with cannulated screws.
Suggesting an "all-anterior" approach for everything or failing to mention the risk of neurovascular injury (specifically the saphenous nerve/vein medially or sural nerve/peroneal tendons posterolaterally) when choosing the approach for the posterior component.
My approach is tiered: First, I utilize the anterolateral approach to secure the sagittal epiphyseal component. If the posterior metaphyseal fragment remains significantly displaced (>2mm), I would not accept a malreduction. I would employ a posteromedial approach, taking care to protect the saphenous nerve and vein. This allows direct visualization to clear soft tissue interposition. I would then use joystick K-wires to achieve reduction. When fixing, I would prioritize parallel screw placement relative to the physis, using partially threaded cannulated screws to achieve interfragmentary compression while attempting to minimize physeal violation.
The patient is now 12 months post-operative. On follow-up, you notice a developing 5-degree varus deformity and limb length discrepancy on the long-leg radiographs. What is your diagnosis, and how do you manage it?
Candidate: The patient has likely developed a physeal bar secondary to the trauma or the surgical fixation. I would obtain an MRI or specialized CT to map the size and location of the bar. Management depends on the percentage of the physis involved; if it is less than 50%, I would consider physeal bar resection with an interpositional material, potentially combined with guided growth if the deformity is progressive.
Forgetting that if the bar is large (>50%), resection is often contraindicated. Candidates often jump to surgery without assessing the remaining skeletal growth potential (e.g., using skeletal age assessment).
This is a post-traumatic physeal bar. I would perform a comprehensive assessment, including skeletal age (e.g., Greulich-Pyle) to determine growth potential. Mapping the bar via MRI is critical. For <50% involvement: If the patient has significant growth remaining, I would discuss bar resection with fat/bone wax interposition. For >50% involvement: Resection is high-risk for failure; I would lean toward contralateral epiphysiodesis to equalize length or, if the deformity is symptomatic, a corrective osteotomy at maturity. This needs to be managed in a multi-disciplinary fashion, involving serial long-leg alignment films until skeletal maturity.
