ARIXTRA Local Study For Registration In China.

Inclusion criteria: * Patients undergoing either an elective major hip or knee replacement or revision. * Signed written informed consent. Men or women of non-child bearing potential(i.e., post menopausal or with hysterectomy of bilateral tubule ligation) or women of childbearing potential without any plan to have a child. Exclusion criteria: * History of serious active bleeding in last 3 month * Concurrent or history of thrombocytopenia ( Platelet\< 100x109/L) * History of hypersensitivity reaction to heparin, Low molecular weight heparin or pork product * Acute bacterial endocarditis * Congenital or acquired bleeding disease in last 3 months * Concurrent uncontrolled ulcer or gastrointestinal disease with blood vessel dysplasia * Concurrent hemorrhagic cerebrovascular disease or surgical history in cerebral, spine or eye * Conditions need to leave a tubule in intradural or extradural * Contraindication to anticoagulant or condition required to take long term oral anticoagulant * Abnormality in hepatic (\>1.5x UNL), renal (Clcr \< 30ml/min) or cardiac function, uncontrolled hypertension or tumor Concurrent disorder of blood vessel in lower limb * Positive result in Human Chorionic Gonadotropin test Participated in any other investigational study on Deep Vein Thrombosis prevention in last 90 days. * Concurrently to have hip and knee or double hip/knee replacement at the same time