Predictors of Deep Infection after Distal Femur Fracture: A Multicenter Study

Objectives:To identify potentially modifiable risk factors for deep surgical site infection after distal femur fracture.Design:Multicenter retrospective cohort study.Setting:Ten Level-I trauma centers.Patients/Participants:Patients with OTA/AO 33A or C distal femur fractures (n = 1107).Intervention:Surgical fixation of distal femur fracture.Main Outcome Measurement:The outcome of interest was deep surgical site infection.Results:There was a 7% rate (79/1107) of deep surgical site infection. In the multivariate analysis, predictive factors included alcohol abuse [odds ratio (OR) = 2.36; 95% confidence interval (CI), 1.17-4.46; P = 0.01], intra-articular injury (OR = 1.73; 95% CI, 1.01-3.00; P = 0.05), vascular injury (OR = 3.90; 95% CI, 1.63-8.61; P < 0.01), the use of topical antibiotics (OR = 0.50; 95% CI, 0.25-0.92; P = 0.03), and the duration of the surgery (OR = 1.15 per hour; 95% CI, 1.01-1.30; P = 0.04). There was a nonsignificant trend toward an association between infection and type III open fracture (OR = 1.73; 95% CI, 0.94-3.13; P = 0.07) and lateral approach (OR = 1.60; 95% CI, 0.95-2.69; P = 0.07). The most frequently cultured organisms were methicillin-resistant Staphylococcus aureus (22%), methicillin-sensitive Staphylococcus aureus (20%), and Enterobacter cloacae (11%).Conclusions:Seven percent of distal femur fractures developed deep surgical site infections. Alcohol abuse, intra-articular fracture, vascular injury, and increased surgical duration were risk factors, while the use of topical antibiotics was protective.Level of Evidence:Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.