The objective of this study is to determine the comparative efficacy and safety of two oral regimens of dabigatran etexilate, compared to a standard subcutaneous regimen of enoxaparin, in prevention o f venous thromboembolism (e.g. deep vein thrombosis of the leg) in patients with primary elective to tal hip replacement surgery.

This is a phase III randomised, parallel group, double-blind, active controlled (double dummy) study to investigate the efficacy and safety of two different dose regimens of orally administered dabiga tran etexilate capsules [150 or 220 mg once daily starting with half dose (i.e. 75 or 110 mg) on the day of surgery] compared to subcutaneous enoxaparin 40 mg once daily for 28-35 days, in prevention of venous thromboembolism in patients with primary elective total hip replacement surgery.

Study Hypothesis:

This trial aims to demonstrate therapeutic equivalence (non-inferiority) of dabi gatran compared with enoxaparin by showing that the rate of total venous thrombo embolic events (VTE) plus all-cause mortality in dabigatran treatment does not e xceed the VTE rate after enoxaparin treatment by more than 7.7%. The correspondi ng null hypotheses of interest are that the difference in rates of total VTE plu s all-cause mortality in dabigatran treatment versus enoxaparin is greater than 7.7%.

Comparison(s):

For the primary comparison the rates of total venous thromboembolic events (VTE) and all cause mortality during the treatment period will be compared. Total VTE is defined as the composite incidence of proximal and distal deep venous thromb osis (DVT), symptomatic DVT and pulmonary embolism (PE).

• Thromboembolism
• Arthroplasty, Replacement, Hip

• Drug: "Dabigatran etexilate (oral, 150 mg once daily)"
• Drug: "Enoxaparin (subcutaneous, 40 mg once daily)"
• Drug: "Dabigatran etexilate (oral, 220 mg once daily)"

Inclusion criteria (selected):

• Patients (18 years or older) scheduled to undergo a primary, unilateral, elect ive total hip replacement
• Written Informed Consent

Exclusion criteria (selected):

• Patients with an excessive risk of bleeding, for example because of history o f bleeding diathesis major surgery or trauma within the last 3 months history of haemorrhagic stroke or any of the following intracranial pathologies: bleedin g, neoplasm, AV malformation or aneurysm clinically relevant bleeding or gastri c / duodenal ulcer within the last 6 months treatment with anticoagulants withi n 7 days prior to joint replacement surgery or anticipated need during the study treatment period thrombocytopenia.
• Active malignant disease or current cytostatic treatment
• Known severe renal insufficiency
• Liver disease expected to have any potential impact on survival, or elevated A ST or ALT > 2x upper limit of normal
• Recent unstable cardiovascular disease or history of myocardial infarction wit hin the last 3 months
• Pre-menopausal women who are pregnant or nursing, or are of child-bearing pote ntial and are not practising or do not plan to continue practising acceptable me thods of birth control
• Allergy to radio opaque contrast media or iodine, heparins (incl. heparin indu ced thrombocytopenia) or dabigatran
• Contraindications to enoxaparin
• Participation in a clinical trial during the last 30 days