Does the Timing, Type, and Method of Flap Coverage After Open Tibia Fracture Fixation Influence the Rate of Deep Infection?

Objectives To evaluate whether the timing of flap coverage following definitive fixation influences deep infection and nonunion in patients with Gustilo‐Anderson (GA) Type 3B and 3C open tibia fractures, accounting for flap method (local vs. free) and tissue type (muscle vs. fasciocutaneous). Methods Retrospective cohort study of patients with GA 3B and 3C tibia fractures treated at a Level I trauma center (2013–2022) with fracture fixation and soft‐tissue reconstruction. Primary outcomes were deep surgical site infection and nonunion, assessed by timing of flap coverage (≤ 72 vs. > 72 h), tissue type, and flap method. Results Fifty‐one patients (52 extremities) met inclusion criteria. Deep infection was significantly higher after free (13/30, 43%) versus local flaps (0/22; p < 0.001). There was a trend toward increased infection rates when coverage occurred >72 h post‐fixation (9/30, 30%) versus ≤ 72 h (4/22, 18%; p = 0.33). Among free flaps, coverage ≤ 72 h had fewer infections (4/13, 31%) than coverage > 72 h (9/17, 53%; p = 0.22). Tissue type and timing had no significant effect: muscle ≤ 72 h (4/20, 20%) vs. > 72 h (8/23, 35%; p = 0.28); fasciocutaneous ≤ 72 h (0/2) vs. > 72 h (1/7, 14%; p > 0.99). Nonunion was more common with free flaps (13/30) than local flaps (2/22; p = 0.007). Free flaps placed ≤ 72 h had fewer nonunions (4/13, 31%) than those placed > 72 h (9/17, 53%; p = 0.22). Conclusions Free flaps were associated with higher rates of deep infection and nonunion. Although not statistically significant, there was a trend toward increased complications with coverage > 72 h, especially for free and muscle flaps.