Functional Outcomes of Tillaux and Triplane Fractures with 2 to 5 Millimeters of Intra-Articular Gap

Background: The treatment of transitional ankle fractures (Tillaux and triplane) is often dictated by the amount of displacement at the articular surface. Although >2 mm is a common indication for operative management, this practice has not been strongly supported by either the pediatric or adult literature. The purpose of this study was 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. Methods: A retrospective review of all patients treated for distal tibial fractures at a single institution between 2009 and 2017 was conducted. Computed tomographic images obtained after closed reduction were reviewed to identify patients with 2 to 5 mm of displacement (either gap or step-off) at the articular surface of the tibial plafond. Complications were classified according to the modified Clavien-Dindo system. Only patients with functional outcome data (Foot and Ankle Ability Measure [FAAM]) at a minimum of 2 years after treatment were included. Two multivariable linear regression models were developed using backward stepwise regression with either the FAAM Sports score or the Single Assessment Numerical Evaluation (SANE) Sports score as the dependent variables. Results: Fifty-seven patients (34 with triplane fractures and 23 with Tillaux fractures) with a mean follow-up of 4.5 years (range, 2.0 to 9.2 years) met inclusion criteria. Thirty-four patients were treated operatively, and 23 patients were treated with closed reduction and cast application. Nonoperative treatment, greater intra-articular gap, and presence of a grade-III complication were associated with worse functional outcomes in both multivariable regression models. A gap after closed reduction remained a negative predictor of functional outcome even in patients who were treated operatively. Patients who were treated nonoperatively and had ≤2.5 mm of gap had a significantly higher mean SANE Sports score at 90% than those patients with >2.5 mm of gap at 75% (p = 0.03). Conclusions: In Tillaux and triplane fractures with 2 to 5 mm of gap at the tibial plafond, a greater gap after closed reduction, nonoperative treatment, and complications were negative predictors of functional outcome at a mean follow-up of 4.5 years. Surgical management likely conveys the greatest functional benefit when the intra-articular gap exceeds 2.5 mm. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.