Preoperative Use of Aspirin in Total Knee Arthroplasty: Safe or Not?

OBJECTIVE: To compare the blood loss, transfusion rates and complications between the aspirin and non‐aspirin group in unilateral and bilateral total knee arthroplasties (TKAs) with a nested case–control design. METHODS: The present study retrospectively selected TKA cases from the Joint Arthroplasty Database at the Peking Union Medical College Hospital from January 2014 to December 2019 following strict inclusion and exclusion criteria, and divided them into the aspirin and non‐aspirin group based on the use of aspirin preoperatively. Bleeding was measured by blood loss, transfusion rate, drainage volume, hemoglobin (HGB) and hematocrit (HCT), while complications (cardiovascular events, venous thromboembolism events, cerebrovascular events and wound events) were compared between the groups. Student's unpaired t‐test and Mann–Whitney U‐test were used to compare the differences of continuous variables between the two groups while chi‐square test and Fisher's exact test were applied in categorical variables. RESULTS: A total of 560 patients with unilateral TKA and 285 patients with bilateral TKA were extracted. Among these, 280 patients used aspirin preoperatively. No other differences were found in demographic and surgical characteristics between the two groups except for the proportion of coronary artery diseases (P < 0.001). For primary outcomes, there was no significant higher blood loss and transfusion rate in the aspirin group, while the drainage of aspirin group was higher than the control group in bilateral TKAs (P = 0.043). The HGB and HCT of the aspirin group was significant lower in both unilateral and bilateral TKAs at POD5 (P < 0.05). For complications, there was a lower vascular related complication rate in aspirin group after unilateral TKAs (P = 0.040), but the wound event rate in aspirin group was higher than the control group (P = 0.049). CONCLUSIONS: Preoperative use of aspirin could prevent vascular related events during the perioperative period of TKA. However, it might also increase the risk of bleeding and wound complications.