Background: Autoimmune disease is associated with chronic systemic inflammation, immunosuppressive therapy, and increased medical comorbidity, which may influence postoperative outcomes following fracture fixation. Data evaluating outcomes after ankle fracture surgery in this population remain limited. We hypothesized that autoimmune disease would be associated with higher postoperative complication rates following open reduction and internal fixation (ORIF) of closed ankle fractures.
Methods: We performed a retrospective cohort study using a multi-hospital dataset (2017-2025) to identify adult patients undergoing ORIF for closed bimalleolar or trimalleolar ankle fractures. Patients with autoimmune disease were propensity score matched 1:2 to patients without autoimmune disease based on age, sex, body mass index, Elixhauser Comorbidity Index, fracture pattern, and relevant medical comorbidities. Outcomes included acute care encounters (defined as presentation to the emergency department or hospital admission), thromboembolic events, postoperative medical complications, and fracture-related complications (malunion, nonunion, revision surgery), within 1 year. Rare outcomes were evaluated using Firth logistic regression.
Results: The matched cohort included 1,879 patients (autoimmune disease, n=627; controls, n=1,252), with well-balanced baseline characteristics. One-year acute care encounter rates were similar between groups (59% vs 58%, P=.72). Pulmonary embolism occurred more frequently among patients with autoimmune disease (5.4% vs 2.9%, P=.006), while rates of deep vein thrombosis were low and comparable. Rates of postoperative medical complications, including pneumonia, myocardial infarction, stroke, acute kidney injury, sepsis, and surgical site infection, did not differ between groups. Fracture-related complications were uncommon overall. Revision surgery or hardware removal within 1 year occurred less frequently in patients with autoimmune disease (0.3% vs 1.5%, P=.070). In adjusted analyses, autoimmune disease was not associated with mortality, acute care encounters, or postoperative medical complications but was associated with lower odds of fracture-related complications (OR 0.57, 95% CI 0.33–0.96; P=.033).
Conclusion: Autoimmune disease was not associated with increased acute care encounters, or overall postoperative medical complication rates following ankle fracture ORIF. Although pulmonary embolism occurred more frequently, fracture-related complications were less common. Autoimmune disease alone should not preclude standard operative management of ankle fractures, though thromboembolic risk may warrant closer perioperative attention.