Aspirin Versus Low-Molecular-Weight Heparin for Extended Venous Thromboembolism Prophylaxis After Total Hip Arthroplasty

Background: The role of aspirin in thromboprophylaxis after total hip arthroplasty (THA) is controversial. Objective: To compare extended prophylaxis with aspirin and dalteparin for prevention of symptomatic venous thromboembolism (VTE) after THA. Design: Multicenter randomized, controlled trial with a noninferi-ority design based on a minimal clinically important difference of 2.0%. Randomization was electronically generated; patients were assigned to a treatment group through a Web-based program. Patients, physicians, study coordinators, health care team members, outcome adjudicators, and data analysts were blinded to interven-tions. (Current Controlled Trials: ISRCTN11902170) Setting: 12 tertiary care orthopedic referral centers in Canada. Patients: 778 patients who had elective unilateral THA between 2007 and 2010