ENhanced Recovery and ABbreviated LEngth of Anticoagulation for Thromboprophylaxis After Primary Hip Arthroplasty

Inclusion Criteria:

1. Written informed consent

2. Age between 18 and 85 years

3. Scheduled to undergo elective unilateral primary THA and eligible for perioperativemanagement based on the ERAS protocol

4. Baseline Timed Up and Go (TUG) test scoring < 20 seconds, corresponding to agood mobility status before surgery

5. Capability to understand and comply with the protocol requirements (e.g., sufficientknowledge of German language to answer the questionnaires, ability to swallow intactcapsules).

6. Pregnancy and contraception:

7. Pregnancy test: Negative serum pregnancy test at screening for women ofchildbearing potential (WOCBP).

8. Contraception: WOCBP and men who are able to father a child, willing to beabstinent or use highly effective methods of birth control that result in a lowfailure rate of less than 1% per year when used consistently and correctlybeginning at informed consent, for the duration of drug treatment and allowingfor a safe wash out period of at least 5 days for female or for male subjectsafter the last dose of trial medication. This is a very conservative estimate,considering the 'worst case scenario' of a substantially prolonged half-life upto 13 hours (e.g., in older patients and/or those with renal dysfunction) (28),and calculating for at least 8 half-lives to ensure practically non-detectablelevels and effects of rivaroxaban.

Exclusion Criteria:

1. Previous DVT or PE

2. Hip or lower limb fracture in the previous three months

3. Major surgical procedure within the previous three months

4. Active cancer defined as metastatic cancer, or cancer requiring chemotherapy orradiation therapy

5. Active peptic ulcer disease, gastritis, or prior gastrointestinal bleeding

6. Obesity with body mass index (BMI) > 40 kg/m2 body surface area

7. Severe renal impairment defined as estimated glomerular filtration rate < 30ml/min

8. Severe hepatic impairment defined as Child Pugh Class B or C

9. Uncontrolled intercurrent illness (i.e., active infection, symptomatic congestiveheart failure, uncontrolled hypertension, unstable angina pectoris, interstitiallung disease, serious gastrointestinal conditions [e.g., diarrhea, malabsorption],psychiatric illness)

10. Active or recent major bleeding at any site, or presence of any major risk factorfor bleeding, which, in the judgment of the investigator, may significantly increasethe bleeding risk during postoperative anticoagulation treatment

11. Any other medical condition representing a contraindication to discharge within 6days after surgery

12. Expected requirement for major surgery within a 90-day period post THA

13. Need for long-term anticoagulation (e.g., atrial fibrillation, previous VTE)

14. Need for chronic antiplatelet therapy except for acetylsalicylic acid (ASA) at adose ≤ 100 mg daily or clopidogrel 75 mg daily

15. Previous participation in this trial

16. Life expectancy < 6 months

17. Participation in another interventional clinical trial within the last 30 days priorto inclusion, unless during the observational follow-up period

18. History of hypersensitivity to the investigational medicinal product (IMP) or to anydrug with similar chemical structure or to any excipient present in thepharmaceutical form of the IMP