Session VIII - Basic Science
·Bioabsorbable Osteoconductive Bone Graft Can Prevent Intramedullary Infection
Purpose: The objective of this study was to evaluate the effectiveness of antibiotic-impregnated calcium sulfate in reducing the establishment of an infection in a contaminated bone defect model. This treatment, because of its bioresorbable and osteoconductive properties, could potentially decrease the number of surgical procedures and associated morbidity.
Methods: A unicortical 12-mm diameter defect was created in the proximal tibial metaphysis of 29 Spanish goats. After contaminating the wounds with 30 µl of 106 CFU/ml of streptomycin-resistant Staphylococcus aureus, the animals were divided into 4 groups. The negative control group received no treatment; the positive control group was treated with hand-prepared tobramycin-impregnated polymethylmethacrylate (PMMA) cement beads; the experimental bone cement group received commercially available tobramycin-impregnated PMMA bone cement beads (Simplex P with tobramycin, Stryker Howmedica); and the experimental calcium sulfate group received commercially available tobramycin-impregnated calcium sulfate pellets (Osteoset T, Wright Medical Group, Inc.). Intraosseous tissue cultures were obtained on postoperative day 21.
Results: The cultures showed no evidence of intramedullary infection in any of the groups that received local antibiotic treatment regardless of the delivery vehicle. Conversely, 8 of 8 goats in the negative control group had positive intramedullary cultures for S. aureus (4.51 x 107 ± 1.65 x 107 CFU/g).
Conclusion/Significance: The data demonstrated that both of the commercially available products were effective in preventing intramedullary S. aureus infection in a contaminated bone defect model. Use of the experimental PMMA bone cement would eliminate the simple procedure of mixing the antibiotic with the cement powder. Use of the experimental calcium sulfate would eliminate all preparation procedures and the need for surgical removal of cement beads; this could reduce both the number of surgeries required and the morbidity associated with open fracture treatment.