Low dose vancomycin-loaded spacers for two-stage revision knee arthroplasty: High success, low toxicity

Background: Two-stage revision arthroplasty is a widely used treatment method for infected knee arthroplasty. Loading high doses of antibiotics to spacer during the first stage is standard practice. However, there are reported systemic side effects attributed to antibiotic-loaded spacers. The aim of our study is to investigate the success rate and systemic toxicity following the first stage revision knee arthroplasty with low-dose vancomycin-loaded spacers. Method: We included patients with infected knee arthroplasty eligible for two-stage revision arthroplasty from 2001 to 2020. One gram of vancomycin is added per pack of bone cement. Spacers were handmade in the operating theatre. Following the first stage, preoperative and postoperative culture results, infection parameters, kidney and liver function tests, and functional scores were analyzed. Kaplan-Meier survival analysis was done to determine the success rate. Results: Fifty patients with a mean follow-up of 48 months (24-108) were included in the study. A five-year survival analysis showed an 88.5% success rate. Fourteen percent of the patients had acute kidney injury with creatinine levels between 1.12-2.80 mg/dl, and 8% had a mild drug-induced liver injury with elevated serum ALT levels between 223-540 U/L and total bilirubin levels between 0.59-1.23 mg/dl. None of the patients required dialysis. All of the systemic side effects were reversible. Conclusion: Our results have suggested that low dose antibiotic-loaded spacers are comparable to the studies with high dose antibiotic loaded spacers regarding infection eradication and survival rates. They are less likely to cause severe systemic side effects. Therefore we suggest low dose antibiotic-loaded spacers should be considered when treating patients with vancomycin sensitive Staphylococcal species and culture negative infected knee arthroplasty.