MacInnis, Bailey R

OBJECTIVES: The aim of this study was to identify the rate at which the anterolateral (AL) tibial plafond is affected in comminuted suprasyndesmotic ankle fractures (OTA/AO 44C2) and to assess how its involvement affects clinical outcomes. METHODS: Design: Retrospective review. Setting: Level 1 Trauma Center. Patient Selection Criteria: Patients with a preoperative computed tomography treated surgically for OTA/AO 44C2 fractures from January 2005 to December 2021. Outcome Measures and Comparisons: The primary outcome measure was the prevalence of AL plafond impaction or a displaced Tillaux-Chaput fracture. Secondary outcome measures included reoperation rate (excluding hardware removal), rate of new-onset ankle osteoarthritis, rate of ankle osteoarthritis progression, Single Assessment Numeric Evaluation score, and the Olerud Molander Ankle Score. RESULTS: Fifty-three patients met inclusion criteria. The average age was 50 years (range 18–100), and 53% were female. The AL plafond was involved in 26 patients (49%), with AL plafond impaction in 11 patients (21%) and a displaced Tillaux-Chaput fragment in 15 patients (28%). Five patients (19%) received independent fixation of the AL plafond, and 3 of these patients had AL plafond impaction addressed. Thirty-eight patients (72%) had clinical follow-up of at least 6 months. Patients with AL plafond impaction had a higher rate of reoperation (excluding hardware removal) compared with those without any AL plafond involvement (hazard of reoperation = 8.3, 95% confidence interval, 1.4–15.3, P = 0.022) and a higher rate of new-onset ankle osteoarthritis (83% vs. 23%, P = 0.013). There was no difference in the rate of reoperation (11% vs. 9%, P = 0.748) or new-onset osteoarthritis (63% vs. 23%, P = 0.078) when comparing those with a displaced Tillaux-Chaput fracture to those without AL plafond involvement. There were no differences in Single Assessment Numeric Evaluation (75% vs. 78% vs. 85%, P = 0.661) or Olerud Molander Ankle Score (70 points vs. 69 points vs. 81 points, P = 0.517) scores when comparing those with AL plafond impaction, those with Tillaux-Chaput fragments, and those with no AL plafond involvement. CONCLUSIONS: Computed tomography evaluation is recommended in patients with comminuted suprasyndesmotic fibula fractures (OTA/AO 44C2) given their high association with AL plafond impaction and Tillaux-Chaput fracture. Patients with AL plafond impaction have a higher reoperation rate and new-onset ankle osteoarthritis compared with those without AL plafond involvement. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.