This study is to identify the following problems and questions with respect to the safety and effectiveness of Xarelto in comparison with other pharmacologic agents in the prophylaxis of venous thromboembolism (VTE) in a large sample of patients who undergo elective total hip replacement (THR) or total knee replacement (TKR) in the real-life conditions in its registered indication(s) as required by Korean Food and Drug Administration (KFDA).

1. Known and unknown adverse reactions, especially serious adverse reactions
2. Incidence of adverse reactions under the routine drug use
3. Factors that may affect the safety of the drug
4. Factors that may affect the effectiveness of the drug
5. Other safety information related to overuse, drug interaction and laboratory abnormalities
6. Other adverse reactions

Inclusion Criteria:

• Female and male patients >/= 18 years of age who will undergo elective total hip replacement or total knee replacement and receive Xarelto or other pharmacologic standard of care Venous Thromboembolism (VTE) prophylaxis, and who consent to participate in the study

Exclusion Criteria:

• Patients with hypersensitivity to any pharmacologic VTE prophylaxis treatment
• Patients with clinically significant active bleeding (e.g., intracranial bleeding, gastrointestinal bleeding)
• Patients with significant hepatic disease which is associated with coagulopathy leading to a clinically relevant bleeding risk
• Pregnant or lactating women
• Patients with hereditary problems of lactose or galactose intolerance (e.g., the Lapp lactase deficiency or glucose-galactose malabsorption)

Patients who will be treated with rivaroxaban or other pharmacologic agents (e.g. LMWH/VKA/Fondaparinux) to prevent VTE after elective total hip replacement or total knee replacement