Background: The morbidity associated with open fractures and open
fracture treatment is well established. An osteoinductive and osteoconductive
bone-graft substitute that prevents infection would decrease the number of
procedures required to treat contaminated fractures by eliminating the need
for surgical removal of cement beads and perhaps autograft harvest. We
hypothesized that the combination of tobramycin-impregnated calcium sulfate
pellets and demineralized bone matrix would prevent the establishment of
infection in a contaminated fracture model.
Methods: A unicortical 12-mm-diameter defect was created in the
proximal tibial metaphysis of twenty-nine Spanish goats. After contaminating
the wounds with an infective dose of Staphylococcus aureus, we
divided the animals into four groups. The negative control group received no
treatment, the positive control group received tobramycin-impregnated
polymethylmethacrylate beads, the demineralized bone matrix group received 2.5
mL of demineralized bone matrix, and the experimental group received
tobramycin-impregnated calcium sulfate pellets with 2.5 mL of demineralized
bone matrix. Radiographs were made and intraosseous tissue cultures were
performed on postoperative day 21.
Results: The cultures showed no evidence of intramedullary infection
in the experimental or the positive control group, but they were positive for
Staphylococcus aureus in six of the seven goats in the negative
control group and seven of the eight goats in the demineralized bone matrix
group.
Conclusions: The combination of tobramycin-impregnated calcium
sulfate pellets and demineralized bone matrix was effective in preventing
intramedullary Staphylococcus aureus infection in a contaminated goat
fracture model.
Clinical Relevance: The local delivery of antibiotic with growth
enhancers can prevent the establishment of intramedullary infection in
association with open fractures. Such a combination therapy could potentially
eliminate the need for surgical removal of cement beads and reduce the number
of autografts harvested, thereby reducing the morbidity of open fracture
treatment.