TRiP-cast Score Validation and Evaluation of Adherence to Preventive Anticoagulant Treatment in Patients With Lower Limb Trauma Requiring Immobilization

Inclusion Criteria: * Age ≥18 years. * Acute lower-limb trauma within 72 hours before enrollment: * Fracture (e.g., foot, ankle, leg, or distal femur) requiring immobilization, or * Grade II or III ankle or knee sprain requiring immobilization, or * Acute Achilles tendon rupture requiring immediate non-surgical immobilization. * Immobilization with a cast or rigid orthosis (e.g., splint or walking boot) expected to last at least 7 days. * Initial outpatient management in an emergency department or outpatient orthopedic/trauma clinic. * No planned hospitalization exceeding 24 hours for the injury or its immediate complications. * Written informed consent provided before study enrollment. Exclusion Criteria: * Planned or initial hospitalization for more than 24 hours. * History of venous thromboembolism within the previous 3 months. * Current oral or injectable anticoagulant therapy for another indication. * Known major contraindication to anticoagulant therapy, including: * Active bleeding. * Untreated active peptic ulcer disease. * Severe thrombocytopenia (platelet count \<50,000/mm³). * Severe hepatic impairment. * Severe renal impairment (estimated creatinine clearance \<30 mL/min using the CKD-EPI equation). * Open lower-limb trauma requiring immediate surgery (except simple fracture reduction and immobilization). * Inability to understand the study procedures or provide written informed consent. * Pregnancy or breastfeeding. * Concurrent participation in another clinical study that may interfere with the objectives of the present study.