Knee arthroplasty tranexamic acid 10-20 mg/kg or 1 g intravenous drip is given either 5-10 minutes before loosening the tourniquet or before cutting the skin (for those who do not use a tourniquet), or tranexamic acid 10-20 mg/kg or 1 g intravenous drip is given again 3 hours after the initial dose. In addition to this, the simultaneous combination of tranexamic acid 1-2g topical application in the joint cavity is also a safe and effective option.