Acute Kidney Injury Following Antibiotic-Loaded Spacer Insertion in Two-Stage Knee Arthroplasty Revision for Periprosthetic Joint Infection: A Retrospective Cohort Study.

Abstract

Antibiotic-loaded cement spacers (ACS) are integral to two-stage revision total knee arthroplasty (TKA) for periprosthetic joint infection (PJI). While effective in infection eradication, concerns have emerged regarding nephrotoxicity due to systemic absorption of high-dose antibiotics. This study aimed to determine the incidence and risk factors for AKI following very high-dose ACS insertion in two-stage revision TKA using a within-patient controlled design. We conducted a retrospective cohort study of 152 patients who underwent two-stage revision TKA with a very high-dose ACS protocol (typically eight grams of antibiotics per 40 grams of cement) at a single high-volume academic center between 2004 and 2023. Patients with recorded pre- and postoperative creatinine values for both stages were included. An AKI was defined per KDIGO criteria. Each patient served as their own control to compare renal function changes between stages. The overall mean follow-up was 7.9 ± 4.3 years. Of the patients, 73% had a spacer with ≥ eight grams of antibiotics per bag of cement (mean = 8.5 grams/bag). An AKI occurred in 6.6% (10 of 152) of patients after the first stage and 2.6% (four of 152) after the second stage (P = 0.10). Repeated measures analysis of variance did not reveal a significant difference in the within-patient creatinine changes between the first and second stages. There were no patients who experienced AKI in both stages. Among AKI cases, 86% resolved to baseline within one month. Only two of the patients who had AKI (20%) had pre-existing chronic kidney disease. Vancomycin (87.1%) and ceftazidime (85.7%) were the most common antibiotics added to the very high-dose spacers. A very high-dose ACS protocol is safe and effective for managing PJI following TKA. Most AKI cases were transient and unrelated to chronic kidney disease, suggesting other modifiable perioperative factors may play a greater role. The precise dosage that optimizes both safety and efficacy has yet to be determined.