Search

Objectives: Local delivery allows a high concentration of antibiotics to be achieved in the wound while avoiding the side effects and cost of systemic administration. Beads molded from polymethylmethacrylate cement are commonly used for local antibiotic delivery but are not ideal. The purpose of this study was to determine whether a bioabsorbable gel delivering vancomycin and gentamicin is more effective in reducing infection than beads delivering vancomycin and tobramycin. Methods: This study used a segmental defect rat model contaminated with Staphylococcus aureus and treated with clinically relevant local antibiotic doses, delivered by gel or beads. In the gel group, 1 mL of gel containing gentamicin and vancomycin was spread throughout the wound. In the bead group, four 3-mm beads containing tobramycin and vancomycin were placed in the wound, 2 in the defect and 2 in the adjacent tissue envelope, there was also a control group that received no antibiotic treatment. After 14 days, bone and hardware was harvested for separate microbiological analysis. Results: There was a significantly lower infection rate in groups treated with antibiotics delivered by gel compared with those treated with either antibiotic beads or no antibiotics at all (P , 0.001). Quantitative cultures also demonstrate significantly less bacteria in the wounds treated with the gel than in the control or bead groups (P # 0.004). Conclusions: These results suggest that antibiotic delivery by a gel is superior to beads. The authors propose that antibiotic depot by polymethylmethacrylate antibiotic beads is less effective because this method has to rely on diffusion of the antibiotic from the high concentration close to the beads to all regions of the wound., Published in the Journal of Orthopedic Trauma, v8 n6 p370-375, Jun 2014. Presented at the Orthopaedic Trauma Association Annual Meeting held in San Antonio, TX on 12-15 Oct 2011. Prepared in collaboration with the Academic Department of Military Surgery and Trauma, Royal Centre for Defence Medicine, Birmingham, UK, and the Infectious Disease Service, Brooke Army Medical Center, San Antonio, TX.

Objectives: The objective of this study is to compare antimicrobial effect of irrigation with chlorhexidine gluconate (CHG) to saline in an animal model. Methods: This study used a segmental defect rat femur model contaminated with Staphylococcus aureus and treated 6 hours after injury with debridement and irrigation with 60 mL of fluid delivered at low pressure. In study groups of 10 animals each, 3 concentrations of CHG (0.5%, 0.05%, and 0.005%) were used and a group irrigated with 0.05% CHG and then saline and a control group treated with saline only. After irrigation the wounds were closed, and the rats were recovered. Fourteen days later, bone and implants were harvested for separate microbiological analysis. Results: There was no statistical difference detected between the subsequent presence or quantity of bacteria after irrigation, with aqueous CHG at a range of concentrations comparing irrigation with saline alone. Conclusions: This study does not support the use of CHG as an irrigant. This may be due to the antibacterial effect of CHG being offset by the associated host tissue toxicity. Host tissue damage from high irrigation pressures and cytotoxic solutions has been shown to allow bacteria to thrive. We believe this is due to a rebound of bacteria growth in a wound bed containing small quantities of necrotic tissue damaged by CHG exposure., Published in the Journal of Orthopaedic Trauma, v26 n12 p728-732, Dec 2012.