Soft tissue coverage before 12 days prevents fracture-related infection in IIIB open tibial fractures in young and healthy patients

Introduction: Gustilo–Anderson type IIIB open tibial fractures carry a high risk of fracture-related infection (FRI) due to extensive soft tissue damage and frequent delays in coverage. Although early orthoplastic intervention lowers infection rates, many trauma centers lack the resources for same-day or early flap coverage. This study aimed to assess the relationship between timing of flap coverage and FRI risk in a young, healthy population, and to define a clinically relevant therapeutic window. Materials and Methods: A retrospective cohort study was conducted at a single Level I trauma center (2012–2023). Patients with GA IIIB tibial fractures were treated under a standardized protocol with strict inclusion criteria. Timing of flap coverage was analyzed using Levene test, Student t test, and ROC curve analysis with the Youden index to determine the optimal infection-risk threshold. Results: Out of 332 open tibial fractures, 41 patients with GA IIIB injuries met inclusion criteria. Mean time to coverage was 24.6 days. FRI occurred in 15 patients (36.6%). Delayed coverage was significantly associated with FRI ( P < 0.001). ROC analysis showed an AUC of 0.83; the Youden index identified <12 days as the optimal cutoff (100% sensitivity, 34.6% specificity). None of the 10 patients treated within 12 days developed FRI, versus 56.6% in those treated later ( P < 0.05). Conclusions: Coverage within 12 days minimizes infection risk in GA IIIB tibial fractures. Although immediate coverage remains ideal, a defined 12-day window offers practical guidance, especially where early orthoplastic care is not feasible.