Arterial and venous thromboembolism represents one of the most common preventable health problems. Patients undergoing surgery, especially hip fracture surgery are at high risk for deep vein thromboembolism (VTE) without thromboprophylaxis. In the absence of prophylaxis, the incidence of fatal pulmonary embolism (PE) after Hip Fracture Surgery (HFS) is reportedly 4%-12%. Provision of thromboprophylaxis to all patients who undergo HFS is recommended.

Rivaroxaban is the first agent of a new class of drugs acting as direct factor Xa inhibitors with oral bioavailability. Highly selective inhibition of factor Xa by rivaroxaban is expected to inhibit the amplified burst of thrombin generation and may result in more effective inhibition of thrombus formation with a favorable safety profile. In Thailand rivaroxaban is indicated for the prevention of VTE in patients undergoing major orthopedic surgery of the lower limbs including surgery for hip fractures. There are limited number of observational studies of rivaroxaban in thromboembolism after hip fracture surgery as the approved indication in most countries are for thromboprophylaxis in hip and knee arthroplasty. The broader indications and the high number of hip fracture surgeries in Thailand allow us to explore a pattern of safety profile particularly bleeding complications and risk factors in patients receiving rivaroxaban thromboprophylaxis after hip fracture surgery.

Inclusion Criteria:

• At least 50 years old in men or post-menopause in women
• Patients, who are undergoing standard surgery for fracture of the upper third of the femur, including femoral head, neck, trochanteric and sub-trochanteric fracture and the surgery is planned within 7 days after admission
• Patients, who are eligible for thromboprophylaxis. Such patients will be enrolled only after physician's decision to prescribe rivaroxaban for thromboprophylaxis has been made. The decision is totally based on standard of medical practice.
• Patients, who agree to participate, return to follow-up visits, and who have signed informed consent to participate in the study.

Exclusion Criteria:

• Trauma affecting more than 1 organ system
• Pathological fracture secondary to malignant disease
• Clinically significant bleeding excluding drainage
• Documented congenital or acquired bleeding disorder
• Patients, who have contraindications for thromboprophylaxis or contraindications to take rivaroxaban according to FDA-approved product label
• Patient on oral anticoagulation therapy in the past 7 days
• Pregnancy or breastfeeding
• Patients who are simultaneously participating in a different study

Rivaroxaban safety profile will be observed in 500 patients