Effects of continuing use of aspirin on blood loss in patients who underwent unilateral total knee arthroplasty

Purpose: Concerning the ongoing debate on the effects of continuing aspirin therapy on blood loss in knee arthroplasty, we conducted a retrospective investigation to test the hypothesis that continuation of aspirin prior total knee arthroplasty (TKA) will not cause more blood loss. Methods: From a database of patients who underwent unilateral TKA between 2011 and 2016, we identified two groups: the aspirin group (patients continued aspirin during perioperative period) and the nonaspirin group (patients had no current or recent history of aspirin usage). We extracted and compared patient demographic information, comorbidity index, baseline serum hemoglobin (Hb), and creatinine level between the two groups. We also compared our primary outcomes, including the total blood loss, transfusion requirement, and length of hospitalization between the two groups. A multivariate logistic regression for analyzing the risk factors of requiring transfusion was performed. Results: We found that apart from preoperative serum creatinine level, there was no difference in the baseline Hb level, perioperative change in Hb, total blood loss, or length of hospitalization between the two groups. The percentage of transfusion utilization was also comparable between the two groups. Our regression analysis shows that the risk of requiring transfusion after TKA is not significantly associated with patients taking aspirin therapy before operation. Conclusion: Patients who underwent TKA with continuation of low-dose aspirin did not result in more blood loss. Current blood loss management has provided sufficient reduction of blood loss to accommodate aspirin therapy perioperatively. We suggest that it is safe to continue aspirin prior to TKA.