ERAS (Enhanced recovery after surgery) programs have been widely adopted in elective orthopaedic practice. Early discontinuation of Intravenous (IV) fluids in order to promote mobilisation and subsequent discharge is a key feature of such programs. However concerns have been raised regarding whether such an approach results in an increased risk of acute kidney injury (AKI).

We set out to determine the incidence of AKI in patients undergoing hip or knee arthroplasty treated as part of an ERAS program where IV fluids are removed before leaving the recovery room. Investigate whether there is a difference in incidence between patients with a pre-operative eGFR ≥ 60 or < 60 (ml/min/1.73m2). In addition to whether patients who sustain an AKI have a longer post-operative hospital stay.

The pre and post-operative blood results of patients undergoing elective total hip and total knee replacements were retrospectively analysed to determine whether they had suffered an AKI during admission. The patient's notes were reviewed for other known causes of peri-operative AKI and the length of their hospital stay.

The overall Incidence of AKI was 9.4%. There was a significant association found between pre-operative eGFR and development of an AKI p = 0.002. The incidence of AKI was 5.8% in patients with a pre-operative eGFR ≥ 60 vs 33.3% in those with an eGFR < 60. The development of an AKI was associated with a longer hospital stay p = 0.042. The median length of hospital stay was 7 days for those who suffered an AKI vs 5 days for those who did not.

Patients undergoing elective lower limb arthroplasty with a pre-operative eGFR < 60 treated as part of an ERAS program where fluids are discontinued before leaving the recovery room are at high risk of developing an AKI. Further studies are required to ascertain whether a longer duration of IV fluids is effective in reducing the incidence of AKI in this group.