Two-staged management of ankle fracture-dislocations with a posterior fragment: computer-tomography-based classification, treatment and its outcome.

Introduction: Trimalleolar fractures are difficult to treat and malreduction can lead to functional impairment. Involvement of the posterior malleolus has a poor predictive value. Current computed-tomography (CT)-based fracture classifications led to an increase in fixation of the posterior malleolus. The aim of this study was to describe the functional outcome after a two-stage stabilisation with direct fixation of the posterior fragment in trimalleolar dislocation fractures.

Materials And Methods: In a retrospective study, all patients presenting with a trimalleolar dislocation fracture, an available CT scan, and a two-stage operative stabilisation including the posterior malleolus by a posterior approach were included. All fractures were treated with initial external fixator and delayed definitive stabilisation including fixation of the posterior malleolus. Next to clinical and radiological follow-up, outcome measures (Foot and Ankle Outcome Score (FAOS), Numeric Rating Scale (NRS), Activity of Daily Living (ADL), Hulsmans implant removal score) and complications were analysed.

Results: Between 2008 and 2019, of 320 trimalleolar dislocation fractures, 39 patients were included. Mean follow-up was 49 months (standard deviation (SD) 29.7, range 16-148). Mean age was 60 years (SD 15.3, 17-84) with 69% female patients. The mean FAOS was 93/100 (SD 9.7, 57-100), NRS 2 (interquartile range (IQR) 0-3) and ADL 2 (IQR 1-2). Four patients showed a postoperative infection, three re-operations had to be performed and implants were removed in 24 individuals.

Conclusion: A two-stage procedure of trimalleolar dislocation fractures with in-direct reduction and fixation of the posterior tibial fragment through a posterior approach leads to good functional outcome scores with a low rate of complications.