Culture Negative Infection After Operative Fixation of Fractures

OBJECTIVES:(1) Compare outcomes of orthopaedic trauma patients with culture-negative infection to those with pathogens identified; (2) identify the incidence of culture-negative infection and describe common characteristics. DESIGN:Retrospective study SETTING:Two level 1 trauma centers PATIENTS:391 patients 16 years or older who underwent irrigation and debridement (I&D) for surgical site infection after having undergone fracture fixation were included. INTERVENTION:Patients underwent I&D with cultures and antibiotic therapy was initiated. MAIN OUTCOME MEASUREMENT:Treatment failure due to unsuccessful eradication of infection and time to union. RESULTS:We found 9% incidence of culture-negative infection. Approximately one third of patients in both groups went on to treatment failure (25% of pathogen-specific infections, 38% of culture-negative infections, p=0.15) and there was no difference between the two groups with regard to time to union (22 vs. 24 weeks, p=0.55). More than one third of patients required subsequent reconstructive procedure and 5% of patients in each group required amputation to control their infection. There was no difference between the groups with respect to use of antibiotics prior to intervention and culture. CONCLUSION:This study confirms the devastating effect that post-operative infections can have and suggests that, with clinical sign of infection, negative cultures do not portend a better prognosis. These entities should be treated in a similar manner to infections with positive cultures. Furthermore, we believe that future studies should not strictly rely on presence of positive intra-operative cultures. Consensus as to what constitutes a clinical infection, in the absence of positive cultures, is needed.