DELAYED LOCAL TREATMENT OF RABBIT TIBIAL FRACTURES WITH BIODEGRADABLECEFAZOLIN MICROSPHERES

The prevention of infection is a primary objective in the treatment of open fractures, The objective of this study was to compare the effica cy of biodegradable, poly (DL-lactide-co-glycolide) cefazolin microsph eres and free cefazolin powder in Staphylococcus aureus contaminated r abbit tibial fractures when treatment was delayed for 2 hours, Fractur es were produced in the tibia of rabbits, inoculated with Staphylococc us aureus, and 2 hours later treated by either direct local applicatio n of cefazolin microspheres or an equivalent dose of free cefazolin po wder, Control animals did not receive antibiotic therapy, The fracture s then were stabilized with a bone plate, and the animals were observe d for 8 weeks, Local antibiotic therapy with biodegradable cefazolin m icrospheres prevented the establishment of infection in all animals, a nd cultures of the tibiae were sterile in all cases, In contrast, clin ical evidence of infection developed in 50% of the rabbits that had be en treated with free cefazolin powder and 71% of the control animals, Staphylococcus aureus was recovered from the tibiae of 75% and 100% of these animals, respectively, The results of this study suggest that l ocal antibiotic therapy with biodegradable, controlled release cefazol in microspheres may be useful for the management of open fractures in humans, even when treatment is delayed for several hours after bacteri al contamination.