High Rate of AKI after Treatment for Infected Knee Replacements

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Acute kidney injury (AKI) develops in nearly 1 out of 5 patients treated with antibiotic-loaded “spacers” for periprosthetic infection after total knee arthroplasty (TKA), reports a study in The Journal of Bone and Joint Surgery.

The retrospective study included 424 patients undergoing surgical treatment for periprosthetic infection after primary TKA at the Mayo Clinic from 2000 to 2017. Treatment included placement of high-dose antibiotic-loaded bone cement (ABLC) spacers in addition to systemic antibiotics. Mean age was 67 years; 15% of patients had pre-existing chronic kidney disease (CKD). AKI was defined as a creatinine increase or 1.5 times baseline or at least 0.3 mg/dL in any 48-hour period.

Nineteen percent of patients developed AKI while the ABLC spacers were in place. Risk of AKI was much higher among patients with pre-existing CKD: 45% versus 14%, odds ratio 5.0. None of the patients with AKI required acute dialysis.

AKI was more likely to occur when higher concentrations of vancomycin or aminoglycosides (over 3.6 g per batch of cement) were used in the ABLC spacers: odds ratio 1.9 and 1.8, respectively. Among patients without pre-existing CKD, independent risk factors for AKI included hypertension, perioperative hypovolemia, and atrial fibrillation. Diabetes trended toward significance.

Patients with AKI were not at an increased risk of a prolonged hospital stay or recurrent periprosthetic infection. At an average 6 years' follow-up, 8 patients had developed CKD, and 4 were receiving dialysis.

Two-stage exchange arthroplasty with ALBC spacer placement and intravenous or oral antibiotics is the most common treatment for periprosthetic infection after TKA. This contemporary cohort study suggests a high rate of AKI among patients undergoing this treatment, particularly those with pre-existing CKD.

Risk factors for AKI include indicators of reduced blood flow to the kidneys as well as high concentrations of vancomycin or aminoglycosides used in the spacers. The researchers add, “[W]hile higher antibiotic doses in ALBC spacers can lead to AKI, these doses are also a crucial factor for infection eradication” [Dagneaux L, et al. Acute kidney injury when treating infected total knee arthroplasties with antibiotic-loaded spacers: Incidence, risks, and outcomes. J Bone Joint Surg Am, published online ahead of print March 29, 2021. doi: 10.2106/JBJS.20.01825; https://journals.lww.com/jbjsjournal/Abstract/9900/Acute_Kidney_Injury_When_Treating_Periprosthetic.185.aspx].