In Reply We thank Chen and colleagues for their insights into potential reasons why the TOBRA trial found that tobramycin plus vancomycin powder applied locally in the wound of periarticular tibial fractures at the time of definitive fixation did not reduce risk of deep surgical site infection compared with vancomycin alone. Notably, in the subgroup of 302 patients with open tibial fractures, tobramycin plus vancomycin was associated with increased deep surgical site infection risk (hazard ratio, 2.08; 95% CI, 1.06-4.37), raising the possibility of harm in this high-risk group.