The Addition of a Non-Steroidal Anti-Inflammatory Drug (NSAID) in Local Infiltration Analgesia During Total Knee Arthroplasty Increases the Risk of Acute Kidney Injury in Patients Who Have Renal Impairment: A Propensity-Matched Retrospective Cohort Study.

Background: Local infiltration analgesia (LIA) is a crucial component of pain management during total knee arthroplasty (TKA). Various formulations of the LIA drug cocktail have been described, with non-steroidal anti-inflammatory drugs (NSAIDs) commonly included. Although NSAIDs are highly effective in improving postoperative pain, they are associated with adverse renal, gastrointestinal, and cardiovascular effects. This study aimed to investigate whether the addition of an NSAID in LIA affects the incidence of acute kidney injury (AKI) in TKA patients, especially those who have pre-existing renal impairment. The secondary aim was to determine overall AKI incidence.

Methods: A retrospective cohort study was conducted on elective, primary TKA patients in a single tertiary institution between January 2020 and April 2024. Data was obtained from a prospectively collected institutional knee arthroplasty registry. Patients were administered LIA intraoperatively, with or without an NSAID (30 mg of ketorolac). The study population was divided into two subpopulations, patients who did or did not have chronic kidney disease (CKD), and analyzed separately. Propensity matching was performed on the CKD group, correcting for age, sex, BMI, ASA score, and presence of diabetes mellitus/hypertension. The outcome of interest was the incidence of AKI. A t-test or Chi-square test was used, where appropriate, to determine the statistical significance of the results.

Results: In patients who had CKD (n = 114), the presence of ketorolac in LIA was associated with a higher AKI incidence (12.7 versus 2.0%, P = 0.041). In patients who did not have CKD (n = 870), the presence of ketorolac in LIA was not associated with a higher AKI incidence (2.0 versus 1.9%, P = 1.0). Overall AKI incidence was 2.6%.

Conclusion: In patients who have CKD, orthopaedic surgeons should be highly cautious of administering ketorolac in LIA during TKA, as it is associated with a higher risk of AKI. Patients who have normal renal function can be safely given ketorolac in LIA without an elevated risk of AKI. Further studies are needed to examine AKI incidence when other NSAIDs are used in LIA.