The effect of autogenous bone graft application on wound contamination

A rat model was created in which contaminated wounds were closed in either the presence or absence of autogenous bone graft. The recipients of bone graft were divided into two groups--one receiving autogenous cancellous bone, the other receiving nonviable autogenous autoclaved cortical bone. Quantitative bacterial cultures were collected both at the time of wound closure and 2 weeks after closure. A significantly increased level of soft-tissue contamination was associated with wound closure in the presence of either type of bone graft, indicating an overall adverse effect on soft tissues. A critical level existed such that at initial bacterial contamination levels greater than 10(4) organisms/g tissue, final contamination levels were significantly elevated. With initial contamination levels less than 10(4) organisms/g tissue, however, final bacterial contamination levels were not significantly different. These results may help explain the different rates of infection that have been reported when delayed primary closure of open fractures is done in conjunction with autogenous bone graft.