The Benefit of Aspirin Chemoprophylaxis for Thromboembolism after Total Knee Arthroplasty

The threat of thromboembolic events after total knee arthroplasty has been substantially reduced during the past decade. Currently, the risk of fatal pulmonary embolism is approximately 0.1%. This is due to a confluence of changes in our medical practices, including early mobilization, less traumatic surgery, increased use of regional anesthesia, pneumatic compression devices, and chemoprophylactic agents. Because many chemoprophylactic agents are associated with an increased risk of bleeding, we have chos en aspirin as our preferred method of chemoprophylaxis. This study seeks to determine if aspirin is as effective as newer chemoprophylactic agents as judged by the prevalence of fatal or nonfatal pulmonary embolus, readmission for deep venous thrombosis, and risk of bleeding. Aspirin was the principle chemoprophylactic agent for 3473 consecutive patients having total knee arthroplasty. All patients were followed for a minimum of 6 weeks. There were nine deaths: two from pulmonary embolism, five cardiac events, one stroke, and one fat embolism. Three cardiac-related deaths occurred in patients for whom pulmonary embolism could not definitively be ruled out. Therefore, the best case and worst case scenarios for fatal pulmonary embolism were 0.06% and 0.14%, respectively. Thirteen patients underwent reoperation for hematoma (0.4%). Therefore, we have demonstrated aspirin combined with early mobilization, regional anesthesia, foot pumps, and improved surgical techniques is safer than and equally efficacious as other chemoprophylaxis agents.

Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.