Acute Kidney Injury (AKI) is an increasingly prevalent complication of lower limb arthroplasty (LLA). Even a transient decrease in kidney function has been shown to be associated with increased mortality and development of subsequent Chronic Kidney Disease (CKD).

We set out to determine which perioperative factors are associated with AKI development at our institution through a retrospective cohort methodology. Patients who underwent primary elective LLA from 01/10/16 to 31/09/17 were included, with relevant perioperative data collected from electronic patient records. AKI was classified according to the Acute Kidney Injury Network (AKIN) criteria.

Overall 6.6% of 686 patients developed an AKI post-operatively. These individuals had a significantly longer length of stay (Median 7 days vs 5 days for no AKI [p<0.001]). Independent predictors of AKI on multivariate regression analysis included: Diabetes (OR 3.10, 95% CI 1.34 to 7.20; p=0.008) CKD (OR 5.07, 95% CI 2.60 to 9.86; p=<0.001) and male sex (OR female sex 0.33, 95% CI 0.17 to 0.63; p=0.001). A model including any of these three risk factors predicted 82.2% of patients with an AKI. The overall AKI rate for this model was 11.2% compared to 2.3% for those without any of the three criteria. Only 11% of patients had IV fluid continued beyond the recovery room.

AKI is a significant problem in LLA. Knowledge of associated risk factors will allow for targeted interventions to decrease AKI incidence. Continuation of IV fluids until the first post-operative morning for high risk individuals may be a simple method of reducing AKI.