The efficacy of tobramycin-containing bone cement with that of systemic cefazolin for treatment of infection in a one-stage revision model is compared. In addition, the value of detecting bacterial DNA after antibiotic treatment was investigated. An implant was inserted into the right tibia of rabbits after inoculation with Staphylococcus aureus. At 28 days, the implant was removed. Subsequently, either plain bone cement with or without systemic administration of cefazolin, or tobramycin-containing bone cement was injected into the medullary canal. The tibiae were cultured 14 days after revision (Day 42), and showed a significant decrease in bacterial counts for both antibiotic groups compared with the control group (p</=0.05). The rate of infection in the tobramycin-cement group was slightly higher (2/9) than in the cefazolin group (0/8), although the difference was not significant. Persistence of bacterial DNA after antibiotic treatment may be the result of delayed clearance of DNA and not a sign of active infection. This animal model shows that in a one-stage revision tobramycin-containing bone cement can reduce size and rate of infection, although systemic cefazolin may be more efficacious. Therefore, the use of antibiotic-containing bone cement combined with systemic antibiotic might provide optimal treatment.
Copyright 2001 John Wiley & Sons, Inc.