Renal function after elective total hip replacement

I read with interest the article ‘Renal function after elec- tive total hip replacement’ (Perregaard et al. 2016). I note that the incidence of acute kidney injury (AKI) in primary elective hip replacements as reported in the study is 2%. I recently undertook a retrospective review of a similar nature in a large teaching hospital setting, evaluating the incidence of acute kidney injury in patients undergoing primary hip and knee replacements during 1 year. It is worthy of note that an algo- rithmic electronic alerting system for acute kidney injury was incorporated recently into several clinical chemisty results reporting systems across the national health service in Eng- land. I used data from this system for my review, and obtained a list of all patients who had electronic alerts generated over the year, and matched it to the operating theatres database over the same time period to obtain fi gures on incidence. The inci- dence was 44/541.