RESUMO
PURPOSE: The aim of the present study was to evaluate and compare the effectiveness of the silver-zinc bioelectric dressing as compared with skin preparation with 2% chlorhexidine or 4% chlorhexidine in reducing the bacterial count on the knee. METHODS: Three groups consisting of 48 healthy volunteers were included. Age range was 23 to 54 years old and 60% of participants were male. Each subject had 1 knee serve as the test and the contralateral as the control. The test site was prepared with either 2% chlorhexidine, 4% chlorhexidine, or a silver-zinc bioelectric dressing and after 24 hours skin cultures were taken and examined for bacterial growth. RESULTS: In the 2% chlorhexidine group 23 of 48 unprepped knees had positive cultures, compared with 9 of 48 prepped knees (P = .003; risk reduction, 4.0 times). In the 4% chlorhexidine group 25 of 48 unprepped knees had positive cultures, compared with 14 of 48 prepped knees (P = .027; risk reduction, 2.6 times). In the silver-zinc bioelectric dressing group 29 of 48 unprepped knees had positive cultures, compared with 7 of 48 prepped knees (P < .001; risk reduction, 8.9 times). There was no difference in the positive skin culture rate between the 3 methods. CONCLUSIONS: Application of the silver-zinc bioelectric dressing was equally effective at reducing skin bacterial load when compared with skin preparation with 2% chlorhexidine or 4% chlorhexidine in healthy volunteers. LEVEL OF EVIDENCE: Basic Science - Microbiology. CLINICAL RELEVANCE: The findings of this study indicate that the use of a bioelectric dressing after knee surgery can match the standard of care of preparing the skin with an antiseptic before surgery.