Extended Venous Thromboembolism Prophylaxis Comparing Rivaroxaban to Aspirin Following Total Hip and Knee Arthroplasty

In this study the investigators want to look at whether using aspirin instead of rivaroxaban (after initial treatment with rivaroxaban) works as well at preventing blood clots while also reducing risk of bleeding and is more cost effective in patients who have either a total hip replacement or total knee replacement.