Antibiotic-loaded biodegradable bone cement for prophylaxis and treatment of experimental osteomyelitis in rats.

A biodegradable, particulate composite bone cement containing gentamicin and vancomycin was used for both treatment and prophylaxis of Staphylococcus aureus osteomyelitis in rats. Osteomyelitis was established by inoculating S. aureus into holes that were drilled in the proximal tibiae and were filled with polymethylmethacrylate (PMMA) cylinders. The cylinders were left in place for 3 weeks. The infections were serially evaluated by clinical and radiographic examination and by quantitative culture for colony forming units (CFUs) at the time the rats were killed. For treatment, cements containing antibiotic were implanted in animals that had established osteomyelitis and were left in place for an additional 3 weeks. Sites treated with biodegradable cement containing antibiotics exhibited significantly fewer CFUs in comparison with controls (p < 0.01). Sites treated prophylactically with the biodegradable cement developed no infections as evaluated by clinical or radiographic criteria or by quantitative culture. At this relatively early time, no significant difference in therapeutic effectiveness was found when either the biodegradable cement or PMMA was used as a carrier for antibiotics.