Risk Factors for Postoperative Infection and Associated Outcomes After Pilon Fracture Fixation: A Propensity-Matched Cohort Study.

Background: Pilon fractures are complex, often involving severe comminution and soft tissue compromise. Risk factors for infection after ankle fracture definitive fixation have been associated with open and/or comminuted fractures and poorly managed diabetes. However, infection risk following pilon fractures have not been well studied, and the effect of infection on other postoperative outcomes have not been widely discussed. This study aims to identify risk factors for developing infection following pilon fracture and assess the effect of infection on postoperative outcomes.

Methods: This study was a retrospective review of patients who presented with a pilon fracture and underwent surgical fixation between January 1, 2013, and June 1, 2023. Only patients with at least 6-month follow-up were included. Demographic data and clinical data were collected. A 2:1 propensity score matching was completed to identify infection and no-infection cohorts.

Results: There were 146 patients included in this study. Following propensity score matching, 2 cohorts were identified, including 24 patients with no infection and 14 patients with infection, following pilon fracture. Gustilo-Anderson classification and AO-Orthopaedic Trauma Association (AO-OTA) Classification did not differ significantly between groups (P > .05). Perioperative characteristics were similar between the 2 cohorts. Mean time to partial weightbearing in weeks was 12.51 (SD 7.6) for the no-infection cohort and 29.61 (SD 28.3) for infection cohort (P = .0198). Mean time to full weightbearing in weeks was 21.06 (SD 9.7) for the no-infection cohort and 35.90 (SD 31.7) for the infection cohort (P = .142). In the infection cohort 50.0% (n = 7) of patients experienced nonunion compared with 4.2% (n = 1) in the no-infection cohort (P < .01).

Conclusion: Although fracture severity classification was not significantly different between groups, infection significantly negatively affected time to partial weightbearing, time to full weightbearing, and nonunion rates.