Bacterially contaminated detached autogenous bone fragments--an experimental study

Bacterially contaminated and uncontaminated standardized autogenous bone fragments were compared in an experimental canine model. Bacterial contamination was effected by immersing in a Staphylococcus aureus suspension of 6 X 10(8)/ml for 15 minutes. The fragments were replaced and either left detached or fixed with a lag screw. In a number of cases bone replacement was combined with transverse osteotomy followed by reduction and fixation with a six-hole neutralization plate based on the AO-principle. Follow-up carried out after six and 12 weeks, comprised radiological, histological, microradiographic, fluorescence microscopic and micro-angiographic investigation. Non-quantitative assessment indicated that the rate of resorption and new bone formation in the bacterially contaminated fragments definitely exceeded that of the uncontaminated fragments. Semi-quantitative findings seemed to confirm these conclusions. After 12 weeks this difference had virtually disappeared, except in loosely replaced infected fragments, which still showed more resorption and new bone formation. Integration of all fragments was good, there was no encapsulation with sequestration.