Complex Open Fractures of the Lower Extremity: What is the Optimal Time from Bone Fixation to Flap Coverage?

Shorter delays from presentation to soft tissue coverage in patients with lower extremity open fractures are associated with fewer infections. Orthoplastic teams should know how long flaps can be safely delayed after internal fixation (IF), rather than presentation, because concurrent life-threatening injuries delay limb salvation. We compared infection rates (IRs) of flap coverage delays within 24, 24 to 72, and over 72 hours of IF.This is a retrospective cohort study of adult patients in a Level I trauma center from 2011 to 2021. Patients sustained Gustilo III lower extremity fractures and received flap coverage after fixation. IRs between various delays of flap coverage were compared. A multivariate logistic regression model (including patient demographics, flap composition, bone fixation technique, perioperative antibiotics, three aforementioned time intervals, time from presentation to flap coverage, and time from fixation to flap coverage) was used to determine significant predictors of infections.Of 274 patients, 76 (27.7%) developed an infection. The average time between fixation and flap coverage was 84.9 hours and 106.6 hours in non-infected and infected patients (p = 0.074). IRs among the time intervals were 23.2%, 25.0%, and 31.5% (p = 0.40). Time from fixation to flap coverage was the only significant predictor of infection (p = 0.04).Time from fixation to flap placement is an effective predictor of wound infection. Although the IRs of the >72-hour group did not reach significance, we believe larger cohorts would yield statistical significance. We recommend soft tissue coverage within 72 hours of IF to mitigate infections.