Aspirin Prophylaxis After Total Knee Arthroplasty

Orthopedists vary in their choice of antithrombotic therapy to prevent deep venous thrombosis (DVT) after hip or knee replacement. In this retrospective study, researchers used data from a Michigan orthopedic registry to compare prophylaxis with aspirin and anticoagulants in nearly 42,000 patients who underwent total knee arthroplasty at 29 hospitals between 2013 and 2015.

Proportions of patients who received prophylaxis with aspirin only, anticoagulants only (e.g., warfarin, low-molecular-weight heparin, direct-acting oral anticoagulants), both, or neither, were 31%, 54%, 13%, and 2%, respectively. The primary outcome — DVT, pulmonary embolism, or death at 90 days — occurred with similar frequency in the groups that received prophylaxis (aspirin, 1.2%; anticoagulation, 1.4%; both, 1.3%) but was higher in the no-prophylaxis group (4.8%). After extensive adjustment for potentially confounding variables, no significant difference in the primary outcome was noted between the aspirin and anticoagulation groups, but the no-prophylaxis group had fivefold higher risk. Rates of serious bleeding were about 1% in all groups.