INTRAOPERATIVE EVALUATION AND LEVEL OF CONTAMINATION DURING TOTAL KNEE ARTHROPLASTY

Abstract

Introduction: Despite numerous articles on intraoperative contamination in total knee arthroplasty (TKA) procedures, the available data on tissue contamination are scarce and mainly based on evaluating bacteriological swabs. Methods: Two hundred and forty specimens, divided between bone and soft tissue, were obtained from 40 consecutive unilateral primaries TKAs. The specimens were evaluated for aerobic and anaerobic bacterial growth. Colonyforming units/gram (CFU/g) were calculated on the contaminated specimens to determine the level of contamination. Results: The contamination rate in intraoperative specimens was 15% during TKA. The contamination level had a mean of 10.6 and a median of 5, ranging from 1-70 CFU/g. The most common contaminating organisms in all samples were Staphylococcus aureus (38.9%) and Staphylococcus epidermidis (30.6%). No clinical infections were detected in TKAs in the follow-up period. Conclusion: The contamination rate during TKA is relatively high, despite the practice of standard preventive measures. Contamination levels, measured by CFU/g, are considered low when compared to the infection threshold of 105 reported in the literature. However, contamination should not be underestimated due to the presence of foreign bodies (implants), which are known to significantly lower this threshold. Level of evidence IV; case series.