BACKGROUND: Total knee arthroplasty is a mature technique for end-stage knee osteoarthritis. The problem of postoperative blood loss has always been a hot issue in clinical discussion. Whether the intramedullar femoral canal is sealed during operation and its effect on blood loss in total knee arthroplasty remain controversial.OBJECTIVE: To evaluate the clinical effect of sealing of intramedullar femoral canal for reducing postoperative blood loss in total knee arthroplasty by meta-analysis.METHODS: English databases such as Cochrane Library, Medline, Embase, PubMed, and Web of science, and Chinese databases such as CBM, VIP, Wan Fang, and CNKI were retrieved for clinical controlled trials concerning whether the intramedullar femoral canal was sealed during total knee arthroplasty. The retrieval time was from database creation to July 2018. The outcome indexes included operation time,24-hour drainage, intraoperative blood loss, 24-, and 72-hour hemoglobin reduction, blood transfusion rate, and complications.RESULTS AND CONCLUSION:(1) Ten articles were included, including 11 clinical controlled trials, involving 1 190 patients(665 cases underwent autologous bone or cement sealing in the intramedullar femoral canal, and 525 cases were not treated with occlusion in the intramedullar femoral canal).(2) The results of meta-analysis showed that sealing of intramedullar femoral canal in total knee arthroplasty reduced the amount of intraoperative blood loss(MD=-16.11, 95%CI=(-23.51,-8.71), P < 0.001), 24-hour drainage(MD=-128.05,95%CI=(-212.06,-44.04), P < 0.001), 24-hour hemoglobin reduction(MD=-0.58, 95%CI=(-1.08, 0.08), P=0.02), blood transfusion rate(OR=0.50, 95%CI=(0.36, 0.68), P < 0.001) and complications(OR=0.44, 95%CI=(0.21, 0.91), P < 0.05). The operation time(P=0.2) and 72-hour hemoglobin reduction(P=0.9) did not differ significantly between groups.(3) These results indicate that based on the existing evidence, sealing of intramedullar femoral canal in total knee arthroplasty can effectively control visible blood loss, reduce drainage, reduce blood transfusion rate and complications, and it is worthy of promotion. [ABSTRACT FROM AUTHOR]