New Bone Foundation in a Chronically-Infected Segmental Defect in the Rat Femur Treatment with BMP-2 and Local Antibiotic

摘要

The overall goal of this research was to improve treatment of infected segmental bone loss associated with combat injuries. Our specific aim was to demonstrate whether human recombinant bone morphogenetic protein-2 (rhBMP-2) and antibiotic delivered locally in a composite carrier, together with administration of systemic antibiotic, could lead to new bone formation in an internally-stabilized segmental defect in a rat femur with a chronic infection from Staphylococcus aureus. It was found that rhBMP-2 maintained its osteoinductive capability despite the presence of chronic infection and colonized hardware, and this property was enhanced by local and systemic antibiotic. No significant new bone was formed unless rhBMP-2 was introduced. In one group, a composite collagen sponge/ceramic-collagen matrix carrier containing 200 micrograms of rhBMP-2 (sponge) and 100 mg of Cefazolin (matrix) was applied to surgically debrided defects, together with 4 weeks of systemic administration of the antibiotic Ceftriaxone. Despite the chronic infection, this treatment induced a substantial amount of newly mineralized callus that connected the ends of the defect 8 weeks after debridement such that there was no significant difference between the torsional failure strength of these treated defects and the intact contralateral femurs. All measures of healing improved over time.