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.