Our purpose of this study is to conduct a prospective randomized controlled trial to investigate the blood-conservation effect of this two topical hemostatic agents in primary TKA procedures in patients with a risk of thromboembolic events. We will also observe if there is increased risk of thromboembolism by use of topical hemostatic agents.

Total knee arthroplasty (TKA) is associated with considerable blood loss and increasing needs for allogenic blood transfusion. Previous studies demonstrated a transfusion rates ranging from 10% to 38% after standard TKAs. Transfusion carries significant risks of cardiopulmonary embarrassment, disease transmission, immunological reaction and postoperative infection.

The major causes of postoperative blood loss following TKA are attributed to surgery itself which induces a considerable activation of the coagulation cascade and local fibrinolysis, the latter is further enhanced after release of the tourniquet at the end of surgery. Tranexamic acid (TXA), an inhibitor of fibrinolysis, was reportedly effective reducing blood loss after standard TKA. Our previous experiences in minimally invasive (MIS) TKA showed that intraoperative infusion of TXA reduced 45% of postoperative blood loss and needs for transfusion from 20% to 4%. However, most of the orthopedic surgeons still hesitate to use TXA systemically in TKAs especially in high risk patients with a potential increase in thromboembolic events following surgery. A recent study by Nishihara et al demonstrated that use of TXA in total hip arthroplasty did not appear to affect the prevalence of either proximal DVT or PE. Another study by Xie J et al also showed the incidence of postoperative VTE was unchanged when TXA was administered in primary unilateral TKA, but in there study the total occurrence of vascular occlusive events was statistically significantly higher (17.55% Vs 9.35%, p < 0.001) in the TXA group. However, in this two studies the patient with high risk of thromboembolic events (ischemic heart disease, chronic renal failure on hemodialysis, cerebral infarction, previous VTE disease, thrombophilia associated with genetic diseases) were excluded.

We believe the topical use of hemostatic agent in patients with high risk of thromboembolism can avoid its systematic effect and decrease its potential perioperative risk of thromboembolic complications (arterial thrombosis, myocardial infarction and pulmonary embolism). Recently, there were some reports demonstrating the cost-effectiveness of topical application of TXA in TKA patients. Besides, thrombin-based hemostatic agents, Floseal®, have been widely used in surgical procedure including gynecology, general surgery, and orthopedics which were still attracting the attention and interest of multitudinous surgeons. Some recent studies demonstrated that topic use of Floseal® in primary TKA can reduce hemoglobin decline and calculated total blood loss after TKA and is not related to adverse reactions or complications such as wound infection, venous thromboembolism events(VTE). But there were another studies showed Floseal® does not reduce blood loss in TKA procedures.

Our purpose of this study therefore is to conduct a prospective randomized controlled trial to investigate the blood-conservation effect of this two topic hemostatic agents and their safety in a primary TKA procedures in patients with risk of thromboembolic events. The first group by topical TXA application, the second group by topical Floseal® application, and the third group of placebo and observe whether there is difference in the the blood-conservation effect by total blood loss calculation, hemoglobin loss and transfusion requirement among these patient groups.

Inclusion Criteria:

History of ischemic heart disease, stroke, or VTE high risk group, such as obesity, varicose vein of the leg, previous history of PE or DVT, hypercoagulability, recent or ongoing treatment for cancer.

After cardiologist or neurologist's evaluation, patients who was classified as low-risk of perioperative risk Advanced knee osteoarthritis, Failure of medical treatment or rehabilitation. Hemoglobin > 11g/dl, No use of non-steroid anti-inflammatory agent one week before operation

Exclusion Criteria:

Preoperative Hemoglobin ≦11 g/dl History of infection or intraarticular fracture of the affective knee Renal function deficiency (GFR < 30 ml/min/1.73m2) Elevated liver enzyme, history of liver cirrhosis, impaired liver function and coagulopathy