Background:Efficacy and safety of platelet-rich plasma (PRP) compared with control for preventing postoperative bleeding after total knee arthroplasty (TKA) is controversial. We performed a meta-analysis of randomized controlled trials (RCTs) to determine whether PRP might reduce blood loss and improve function following TKA.Methods:PubMed, Medline, Embase, Web of Science, and the Cochrane Library were searched to identify RCTs comparing PRP with control for patients undergoing unilateral TKA. The mean difference (MD) of total blood loss, hemoglobin (Hb) level, Hb drop, drain volume, range of motion (ROM), Western Ontario and McMaster Osteoarthritis Index (WOMAC) scores, length of hospital stay (LOS), and odds ratios of transfusion rate and postoperative complications in the PRP and control groups were pooled throughout the study. Relevant data were meta-analyzed using RevMan v5.3.Results:Six RCTs involving 529 patients were included (208 PRP vs. 321 controls). The application of PRP in TKA had a significantly less calculated total blood loss (MD=-98.11; 95% confidence interval [CI]: -153.63 to -42.59, P=.0005) and lower Hb drop (MD=-0.34; 95% CI: -0.59 to -0.09, P=.008) than the control in the early postoperative period while decreasing the LOS (MD=-2.12; 95% CI: -3.47 to -0.76, P=.002). No significant differences were seen in drain volume, Hb level, transfusion rate, ROM, WOMAC scores, and complications between the 2 groups (P>.05).Conclusions:Our meta-analysis suggests that PRP appears to be effective in reducing postoperative blood loss and lowering Hb drop without increasing the risks of postoperative complications after TKA. However, owing to the variation of included studies, no firm conclusions can be drawn.