• To determine the therapeutic window of BIBR 1048 in order to select doses for further studies in the development plan.
• Twice daily regimen will be tested for most dose levels and once daily administration will also be evaluated when appropriate.

Inclusion Criteria:

• Patients scheduled to undergo a primary elective total hip replacement
• Male of female being 18 years or older
• Patients weighing at least 40 kg
• Written informed consent for study participation

Exclusion Criteria:

• Bleeding diathesis, constitutional or acquired coagulation disorders
• Major surgery or trauma (e.g. hip fracture) within the last three months. Patients with previous hip fractures associated with plate revisions at any time will be excluded
• Cardiovascular disease including uncontrolled hypertension at time of enrolment or history of myocardial infarction within the last 6 months
• Any history of haemorrhagic stroke, intracranial or intraocular bleeding or cerebral ischaemic attacks
• Known history of deep venous thrombosis (DVT)
• Gastrointestinal or pulmonary bleeding within the last year
• Known liver disease Aspartate transaminase (AST) or Alanine transaminase (ALT) > 3 x ULN)
• Known renal disease (serum creatinine > 1.5 x ULN)
• Use of long- term anticoagulants, antiplatelet drugs, or fibrinolytics within 7 days prior to hip replacement operation (also contraindicated during the period of prophylaxis)
• Women of childbearing potential
• Known allergy to radiopaque contrast media
• Known thrombocytopenia (prior platelet count below 100,000 cells/microliter)
• Active malignant disease
• Current H2 blocker or proton pump inhibitor treatment
• Current cytostatic treatment
• Treatment with an investigational drug in the past month
• Leg amputee
• Known alcohol or drug abuse