In 2007 we published an animal study (Yarboro S, Baum E, Dahners L: Locally Administered Antibiotics for Prophylaxis Against Surgical Wound Infection. Journal Bone Joint Surgery 2007 89(5)) documenting that injecting gentamicin into contaminated wounds after closure of the incision results in several orders of magnitude reduction in bacteria counts as opposed to systemic cephalosporins such as are usually given to prophylax against infection. This results in high concentrations in the wound cavity which are not achieved by IV administration and by injecting it after wound closure it is not removed before closure like antibiotic irrigation solutions. It worked significantly better than sustained release pellets at reducing bacterial counts. I have incorporated this into my trauma practice by injecting (80mg gentamicin in 40cc saline, inject enough to fill the wound) a gentamicin solution after the wound is closed and been very pleased with the reduction in the numbers of infections, especially in open fractures. Data that we published in the August 2009 JBJS suggest that systemic cephalosporins and local gentamicin have a large synergistic effect, so I would recommend doing both.

Dr. Dahners is a Professor of Orthopaedic Surgery at the UNC School of Medicine in Chapel Hill, NC, USA.  His clinical focus is on trauma and his research interests are in ligament physiology, ligament healing, ligament growth and contracture, and bone healing and the biomechanics of internal fixation.  You can see his “Pearls” of orthopaedics on OrthopaedicList.com.

Dr. Dahners et al published “Better Prophylaxis Against Surgical Site Infection with Local as Well as System Antibiotics.  An in Vivo Study” in the August 2009 issue of the Journal of Bone and Joint Surgery.