Thirty day low-dose versus regular-dose aspirin for venous thromboembolism prophylaxis in primary total joint arthroplasty.

Background: The optimal dosing of aspirin (ASA) monotherapy for prophylaxis after total joint arthroplasty is debatable. The objective of this study was to compare two ASA regimens with regards to symptomatic deep venous thrombosis (DVT), pulmonary embolism (PE), bleeding, and infection 90 days after primary total hip arthroplasty (THA) and total knee arthroplasty (TKA).

Methods: We retrospectively identified 625 primary THA and TKA surgeries in 483 patients who received ASA for 4 weeks post-op. 301 patients received 325 mg once daily (QD) and 324 patients received 81 mg twice daily (BID). Patients were excluded if they were minors, had a prior venous thromboembolism (VTE), had ASA allergy, or received other VTE prophylaxis drugs.

Results: There was a significant difference in rate of bleeding and suture reactions between the two groups. Bleeding was 7.6% for 325 mg QD and 2.5% for 81 mg BID (p = .0029 Χ², p = .004 on multivariate logistic regression analysis). Suture reactions were 3.3% for 325 mg QD and 1.2% for 81 mg BID (p = .010 Χ², p = .027 on multivariate logistic regression analysis). Rates of VTE, symptomatic DVT, and PE were not significantly different. The incidence of VTE was 2.7% for 325 mg QD and 1.5% for 81 mg BID (p = .4056). Symptomatic DVT rates were 1.6% for 325 mg QD and 0.9% for 81 mg BID (p = .4139). Deep infection was 1.0% for 325 mg QD and 0.31% for 81 mg BID (p = .3564).

Conclusion: Low-dose ASA in patients with limited comorbidities undergoing primary THA and TKA is associated with significant lower rates of bleeding and suture reactions than high dose ASA. Low-dose ASA was not inferior to higher dose ASA for the prevention of VTE, wound complications, and infection 90 days postoperatively.