ObjectivesTo systematically review the efficacy and safety of controlled hypotension for total hip or knee replacement.MethodsPubMed, EMbase, The Cochrane Library, CNKI, WanFang Data and CBM databases were electronically searched to collect randomized controlled trials (RCTs) on controlled hypotension for total hip or knee replacement from inception to September 2019. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies, then, meta-analysis was performed by RevMan 5.3 software.ResultsA total of 15 RCTs involving 854 patients were included. The results of meta-analysis showed that compared with no controlled hypotension during surgery, controlled hypotension could reduce intraoperative blood loss (MD=−267.35, 95%CI −314.54 to −220.16, P<0.000 01), allogeneic blood transfusion (MD=−292.84, 95%CI −384.95 to −200.73, P<0.000 01), and 24 h postoperative mini-mental state examination (MMSE) score (MD=−1.08, 95%CI −1.82 to −0.34, P=0.004). However, there were no significant differences in 96 h postoperative MMSE score (MD=−0.11, 95%CI −0.50 to 0.28, P= 0.57) and intraoperative urine volume (MD=57.93, 95%CI −152.57 to 268.44, P=0.59).ConclusionsThe current evidence shows that controlled hypotension during total hip or knee replacement can reduce intraoperative blood loss and allogeneic blood transfusion. Furthermore, there is no obvious effect on the maintenance of blood perfusion in important organs, despite certain effects on the postoperative cognitive function, which can be recovered in short term. Due to limited quality and quantity of the included studies, more high quality studies are required to verify above conclusions.