Treatment of osteomyelitis with a biodegradable antibiotic implant.

A biodegradable antibiotic implant was developed and evaluated in a localized osteomyelitic rabbit model. The biodegradable antibiotic implant was made of polylactic acid and poly(DL-lactide):co-glycolide combined with vancomycin. Localized rabbit tibial osteomyelitis was developed with Staphylococcus aureus. Infected rabbits were divided into eight groups, depending on treatment with or without debridement, systemic antibiotics, or biodegradable beads. After 4 weeks of therapy, the radiographs were obtained of the involved bones, which also were cultured for concentrations of Staphylococcus aureus per gram of bone. Treatment with antibiotic containing polylactic acid and poly(DL-lactide):co-glycolide beads, with and without systemic vancomycin, resulted in bone colony forming unit levels of 10(2.93) and 10(2.84) colony forming units per gram bone, respectively. These bacterial concentrations were approximately 100 times lower than those observed for all other treatment groups. A biodegradable antibiotic bead may provide extended bactericidal concentrations of antibiotics for the time needed to completely treat the particular orthopaedic infection and does not require the surgery needed to remove the polymethylmethacrylate beads.