This is a local registration study in China to compare the safety and efficacy of ARIXTRA to Enoxaparine in patients undergoing elective major hip or knee replacement or a revision of components.

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