Increase in fracture-related infection in open distal femur fractures treated with locally delivered antibiotics

Abstract Objectives: Local antibiotic delivery may reduce fracture-related infections (FRIs), but its efficacy in distal femur fractures remains unclear. This study evaluated (1) usage patterns of local antibiotics in distal femur fractures and (2) their impact on infection rates in open distal femur fractures. Methods: Design: Retrospective cohort study. Setting: Single Level I Trauma Center. Patients Selection Criteria: Operatively treated OTA 33 distal femur fractures (2018–2022) with ≥6-month follow-up or diagnosed FRI. Outcome Measures and Comparisons: The primary outcome was FRI. Secondary outcomes were estimated blood loss, operative time, and reoperation. Outcomes were compared between patients with and without local antibiotics in open fractures. Results: Of 135 distal femur fractures, 41 received local antibiotics (15 sustained delivery, 26 topical only). Of 44 open fractures, 24 received local antibiotics. Among the open fractures, FRIs occurred in 5/24 (20.8%) patients with local antibiotics versus 1/20 (5.0%) without. The median time to FRI diagnosis was 151 (range 28–199) days with local antibiotics vs 170 (range 32–307) days without. There was a higher, nonsignificant rate of FRI with local antibiotic use ( P = 0.19). Conclusion: Local antibiotic use was not associated with reduced FRI rates in open distal femur fractures. Although underpowered, the fourfold increase in FRIs among open distal femur fractures that received local antibiotics warrants further investigation. Level of Evidence: Therapeutic Level III.