Silver antibacterial bone cement. Comparison with gentamicin in experimental osteomyelitis

An animal model was used to evaluate and compare silver methacrylate with gentamicin methacrylate in experimental Staphylococcus osteomyelitis. One tibia from each of 54 rabbits was innoculated with 4 X 10(6) CFU of S. aureus and inserted with prepolymerized PMM rods containing either 1% Ag2SO4, 2.5% gentamicin, or no additives. By six weeks, the mortality rate was 61% in controls, 22% in Ag-PMM animals and 6% in gentamicin-PMM animals. Bacterial counts from the bone of dying and surviving animals were significantly lower than controls, 23.6% of controls for the Ag-PMM treated and 6.0% for the gentamicin-PMM treated groups. All surviving animals were culture positive, except for three sterile bones obtained from the gentamicin-PMM group. In light of these results and the favorable characteristics as an antimicrobial agent, further investigation of silver in bone cement (or other vehicles) for the prevention or treatment of bone infection appears warranted.