Acute kidney injury in patients undergoing elective primary lower limb arthroplasty

Recent research has outlined the increasing incidence of acute kidney injury (AKI) and its effect on morbidity/mortality. There is evidence that current rates are significantly under-reported nationally, with uncertainty about pre-operative factors that might influence AKI reduction and the impact on other healthcare outcomes such as mortality and later Chronic Kidney Disease (CKD) development. We set out to help address these current deficiencies in the literature.

A retrospective cohort study was undertaken using data collected from patients undergoing elective primary lower limb arthroplasty within our institution from 01/10/16-31/09/17 with a 2-year follow-up.

53/782 (6.8%) patients had an AKI during the study time period. This was associated with a longer inpatient stay (p < 0.001). There was no significant difference in 30-day mortality (p = 0.134), 30-day readmission (p = 1.00) or later CKD development (p = 0.63). Independent predictors of AKI were as follows: Diabetes (OR 2.49; 95%CI 1.15-5.38; p = 0.021), CKD (OR 4.59; 95%CI 2.37-8.92; p < 0.001) and Male sex (OR 2.61; 95%CI 1.42-4.78; p = 0.002).

AKI in those undergoing hip and knee arthroplasty remains under-reported at a national level. AKI development was associated with an increased length of stay, but not long-term healthcare outcomes. This may be due to the mechanism of AKI development or the low absolute numbers of AKI suffered. We have identified three pre-operative factors (Diabetes, CKD & Male Sex) that were independently predictive of AKI. Targeted interventions may reduce the risk of AKI after lower limb arthroplasty.