Clinical Research Directory

Inclusion Criteria: * Patients with advanced osteoarthritis of the knee and undergo primary unilateral minimally invasive TKA * Age \> 50 years and \< 90 years * Failure of medical treatment or rehabilitation * Hemoglobin ≧ 11g/dl * No use of non-steroid anti-inflammatory agent, antiplatelets or anticoagulants at least 3 days before operation Exclusion Criteria: 1. Preoperative Hemoglobin \<11 g/dl 2. History of infection or intraarticular fracture of the affective knee 3. Renal function deficiency (GFR \<30 ml/min/1.73m2) 4. Elevated liver enzyme (AST/ALT level are more than twice normal range) , history of liver cirrhosis, impaired liver function(elevated total bilirubin level) and coagulopathy (including long-term use anticoagulant) 5. History of deep vein thrombosis, ischemic heart disease or stroke, in which life-long oral anticoagulant are required. 6. Contraindications of tranexamic acid, or rivaroxaban 7. Allergy to tranexamic acid, kaolin, rivaroxaban, or the excipients 8. History of heparin-induced thrombocytopenia (HIT) 9. Coagulopathy or bleeding tendency caused by organ dysfunction, such as cirrhosis, bone marrow suppression etc. 10. Patient who have active bleeding disorder, such as intracranial hemorrhage, upper GI bleeding, hematuria..