Does continued aspirin mono-therapy lead to a higher bleeding risk after total knee arthroplasty?

Background: Evidence about the risk of bleeding and thromboembolism because of aspirin mono-therapy in total knee arthroplasty (TKA) is scant. We wanted to validate the risks of bleeding and thromboembolism with continued aspirin mono-therapy in unilateral and simultaneous bilateral TKA.
Methods: We enrolled a series of 1655 patients who underwent unilateral or simultaneous bilateral TKA between December 2010 and December 2012. Drainage amount, postoperative hemoglobin level, change in hemoglobin, calculated blood loss, incidence and the amount of blood transfused, and the proportion of thromboembolic events were compared between patients who were and patients who were not on continued aspirin mono-therapy.
Results: Calculated blood loss (969.1 ± 324.9 vs. 904.0 ± 315.5 ml), transfusion amounts (1.3 ± 1.5 vs. 1.0 ± 1.3 IU), and percentage of transfused patients (53.0% vs. 40.2%) were higher in unilateral TKA patients on continued aspirin mono-therapy. Outcome parameters and the proportion of DVT between groups were not significantly different. One patient (0.3%) not on aspirin mono-therapy developed a pulmonary embolism, and two others (0.6%) had cerebrovascular events.
Conclusion: Despite the slightly higher risks of bleeding, continuing aspirin mono-therapy during TKA might be safe with low risks of perioperative cerebrovascular, cardiovascular, and venous thromboembolic events.