We will investigate the efficacy and safety of using tranexamic acid by intravenous, intra-articular and combinational administration to reduce blood loss during total knee replacement. We hypothesize a combined intra-articular and single intravenous dose protocol of tranexamic acid may achieve a higher therapeutic concentration at the intra-articular and extra-articular bleeding site with little or no systemic absorption and subsequent systemic side effects.

A randomized, double-blind, single-center, controlled and parallel-assigned study comparing the efficacy and safety of intravenous, intra-articular and combinational administration of tranexamic acid to reduce blood loss during total knee replacement. Subjects will be monitored for occurrence of any complications, particularly deep venous thrombosis and thromboembolism during the hospital stay and for 3 months postoperatively.

Inclusion Criteria:

• Adult patients who plan to undergo primary total knee arthroplasty on unilateral knee joint with a diagnosis of osteoarthritis or aseptic bone necrosis, but not of rheumatoid arthritis;
• All patients who have normal preoperative platelet count, normal prothrombin time, normal partial thromboplastin time, and normal international normalized ratio;
• The use of only balanced electrolyte solutions and/or albumin for plasma volume restitution

Exclusion Criteria:

• Allergy to tranexamic acid;
• Receiving warfarin or heparin; had a history of hemophilia, deep venous thrombosis, pulmonary embolism, or renal impairment; or were pregnant;
• Patients with any cardiovascular problems (such as myocardiac infarction history, atrial fibrillation, angina);
• Patients with thromboembolic disorders, or those exhibiting a deteriorating general condition;
• Preoperative anemia (a hemoglobin value of <11 g/dL in females and <12 g/dL in males), refusal of blood products;
• Preoperative use of anticoagulant therapy within five days before surgery, fibrinolytic disorders requiring intraoperative antifibrinolytic treatment, coagulopathy (as identified by a preoperative platelet count of <150,000/mm3, an international normalized ratio of >1.4, or a prolonged partial thromboplastin time [>1.4 times normal]).