Open fracture infection following combat trauma : defining the problem and evaluating novel treatments

Abstract

The British military was engaged in combat operations in Iraq and Afghanistan over a 12-year period from 2003 to 2014. It has been asserted that over this time survival after combat injury improved generating a cohort of patients with complex limb injuries, including open fractures, which are prone to infection and challenging to reconstruct. Using an anatomic measure of injury severity I demonstrate an improvement in survival after combat injury. I further tested this finding by devising a military specific version of an anatomic-physiological injury scoring system, which confirmed the survival improvement. The UK military trauma registry was used to determine that the most frequently fractured bone was the Tibia and 65% of these fractures were open. Of these, 23% were surgically treated for infection in the first year and S. aureus bacteria was the causative organism in 60%. Infection was significantly associated with amputation or unplanned revision surgery. To further investigate open fracture infections in a controlled setting, an established rodent model of a stabilised, S. aureus contaminated, femoral defect was refined. This model was used to investigate the relationship between timing of treatment and infection. The results of this study indicate that delaying antibiotics administration has a greater effect on infection rates than delaying surgery and that early antibiotics can reduce the greater infection seen with surgical delay but not negate its effect entirely. Novel treatments with potential to reduce infection in open fractures were then evaluated. Chlorhexidine was found to be similar to saline for wound irrigation with respect to preventing infection. A novel biodegradable antibiotic gel proved to be superior at preventing infection in the model than the existing clinical standard local antibiotic delivery vehicle: bone cement (Polymethylmethacrylate) beads. Finally Bismuth Thiols were demonstrated to potentiate the effect of antibiotics in preventing infection.