Systemic Exposure and Renal Safety After Intrawound Vancomycin Powder in Primary Total Knee Arthroplasty: A Prospective Comparative Cohort Study.

BACKGROUND: Periprosthetic joint infection (PJI) is a devastating complication after total knee arthroplasty (TKA). Intrawound vancomycin powder has been proposed as a local prophylactic measure, but concerns remain regarding systemic absorption and nephrotoxicity. This study evaluated systemic absorption, renal safety, and postoperative infection outcomes after intrawound vancomycin use in primary TKA.

METHODS: This prospective comparative cohort study included 260 patients who underwent primary TKA at a single tertiary care center: 130 in the vancomycin cohort and 130 in the control cohort. The vancomycin cohort received one gram of intrawound vancomycin powder before closure. Serum vancomycin levels were measured 12 hours postoperatively. Serial renal function and kidney disease: Improving Global Outcomes (KDIGO)-defined acute kidney injury (AKI) was analyzed in all patients. Infection and wound-complication outcomes were assessed in patients who completed at least six months of follow-up.

RESULTS: The 12-hour serum vancomycin levels were below the laboratory reporting threshold (less than 1.00 mg/L) in 104 of 130 patients (80.0%). Among the remaining 26 patients who had numerical values, the median concentration was 0.28 mg/L (interquartile range [IQR], 0.21 to 1.26; range, 0.01 to 2.76 mg/L), which was well below systemic therapeutic levels. Serum vancomycin concentration was not correlated with early changes in serum creatinine or estimated glomerular filtration rate (Spearman ρ range, -0.08 to -0.03; all P ≥ 0.720). AKI occurred in nine patients (6.9%) in the vancomycin group and eight patients (6.2%) in the control group (odds ratio, 1.13; 95% confidence interval [CI], 0.42 to 3.04; P = 1.000). All AKI events in the vancomycin group were stage 1. Surgery-related complication rates were similar between groups, with no statistically significant differences in PJI, superficial infection, or wound dehiscence.

CONCLUSION: Intrawound administration of one gram of vancomycin powder in primary TKA resulted in minimal systemic exposure and showed no clinically meaningful nephrotoxicity signal. However, it was not associated with a statistically significant reduction in infection or wound-complication outcomes; therefore, these data do not support its routine prophylactic use in primary TKA.