Incidence and risk factors of acute kidney injury after total joint arthroplasty; a retrospective cohort study.

BACKGROUND

Acute Kidney Injury (AKI) is a common complication post-arthroplasty, although it has not been extensively studied. We carried out a retrospective study to determine the incidence and risk factors of AKI in patients undergoing total joint arthroplasty (TJA).

METHOD

We reviewed the medical records of all patients who underwent elective TJA from December 2014 to January 2017 at the Salford Royal Hospital, UK. AKI was defined using the AKIN, RIFLE and KDIGO criteria in patients with worsened renal function post-arthroplasty. We analysed the association of the demographics, risk factors, medications and use of peri-operative IV fluids with AKI. A logistic regression was performed to find any correlation between these factors and incidence of AKI.

RESULTS

197 patients were included in our study, the mean age was 70.2 and male to female ratio was 6:5. Of these, 32(16.2%) developed an AKI. The multivariate logistic regression revealed 4 independent factors associated with the risk of AKI; age (P = 0.0011, OR 1.07, 95% CI 1.03-1.18), obesity (P = 0.003, OR 6.4, 95% CI 2.34-17.5), smoking (P = 0.0482, OR 3.76, 95% CI 1.01-14.0) and COPD (P = 0.0253, OR 3.85, 95% CI 1.18-12.5).

CONCLUSION

The incidence of AKI post-arthroplasty was found to be much higher than stated in other literatures. The recognition of the high incidence and multiple independent risk factors will allow a better approach to peri-operative management, limiting the risks of AKI. Our study also highlighted the importance of documenting urine output and the need to repeat the renal function test 3 months after an AKI to assess recovery.