<![CDATA[Background: Posterior complex fracture-dislocation of the elbow is a severe traumatic injury involving elbow dislocation accompanied by fractures of important osseous stabilizers. The direction and energy of trauma may determine which stabilizing structures fail and, consequently, which fracture-dislocation pattern develops. However, clinical evidence directly evaluating the association between injury mechanism and specific posterior complex fracture-dislocation patterns remains limited, particularly in Indonesia. Objective: To analyze the association between injury mechanism and the type of posterior complex fracture-dislocation of the elbow in adult patients treated at Haji Adam Malik General Hospital, Medan. Methods: This analytical observational study used a cross-sectional design. A total of 48 adult patients with posterior complex fracture-dislocation of the elbow who met the study criteria were included. Data were obtained from medical records and radiological examinations during the period from January 1, 2020 to December 31, 2025. Injury mechanisms were categorized as fall on an outstretched hand (FOOSH) or direct injury. Radiological patterns were categorized as posterolateral, posteromedial, Monteggia apex anterior, Monteggia apex posterior, or trans-olecranon fracture-dislocation. Demographic variables included age, sex, body mass index (BMI), and injured side. Because the assumptions for the Pearson chi-square test were not fulfilled, the Fisher–Freeman–Halton exact test was used to assess the association. Results: The mean age was 41.85 ± 14.76 years, with the largest age group being 30–39 years (25.0%). Men accounted for 52.1% of patients, 41.7% were overweight, and 75.0% sustained left-sided injuries. FOOSH was the predominant injury mechanism (64.6%), while direct injury accounted for 35.4%. The posterolateral pattern was most frequent (56.2%), followed by posteromedial (25.0%), Monteggia apex posterior (8.3%), trans-olecranon (8.3%), and Monteggia apex anterior (2.1%) patterns. Among FOOSH injuries, 83.9% were posterolateral, whereas direct injuries were predominantly posteromedial (47.1%), followed by Monteggia apex posterior (23.5%) and trans-olecranon (17.6%). The association was statistically significant (p < 0.001), with a strong effect size (Cramer's V = 0.775). Conclusion: Injury mechanism was strongly associated with the type of posterior complex fracture-dislocation of the elbow. FOOSH was predominantly associated with posterolateral injury, whereas direct injury was more commonly associated with posteromedial, Monteggia, and trans-olecranon patterns. A detailed history of the injury mechanism may therefore assist early clinical suspicion, radiological evaluation, and treatment planning.]]>
