Silver-coated megaendoprostheses in a rabbit model--an analysis of the infection rate and toxicological side effects.

Deep infection of megaprostheses remains a serious complication in orthopedic tumor surgery. Despite the use of systemic and local antibiotic prophylaxis the reported infection rate is between 5% and 35%. Silver-coated medical devices proved their effectiveness in reducing infections. The objective of this study was to examine in vivo the antimicrobial efficacy and possible side-effects of a silver-coated megaprosthesis. In a first study, 30 rabbits (15 titanium versus 15 silver-coated Mutars-endoprostheses) were infected with Staphylococcus aureus. In a second study, toxicological side effects were analyzed in 10 rabbits with a silver-coated megaprosthesis. The silver group showed significantly (p<0.05) lower infection rates (7% versus 47%) in comparison with the titanium group. Measurements of the C-reactive-protein, neutrophilic leukocytes, rectal temperature and body weight showed significant (p<0.05) lower signs of inflammation in the silver group. The analysis of the silver concentration in blood (median 1.883ppb) and in organs (0.798-86.002ppb) showed elevated silver concentrations without pathologic changes in laboratory parameters and without histological changes of organs. In conclusion, the new silver-coated Mutars-megaprosthesis resulted in reduced infection rates without toxicological side effects, suggesting that this prosthesis might be a promising device in tumor surgery exhibiting antimicrobial activity.