Comparison of pharmacologic prophylaxis in prevention of venous thromboembolism following total knee arthroplasty.

BACKGROUND: Anticoagulants are used following total knee arthroplasty (TKA) to prevent venous thromboembolism (VTE). These drugs reduce VTE risk but may lead to bleeding-related complications. Recently, surgeons have advocated using antiplatelet agents including aspirin (ASA). However, there is no consensus regarding which medication has the optimal risk/benefit profile. The purpose of this study was to compare rates of VTE using different anticoagulants in anticoagulation-naïve patients being discharged home after TKA.

METHODS: A national private insurance database was used to identify patients undergoing unilateral TKA. Patients with a prior history of VTE were excluded. Anticoagulants included ASA, low molecular weight heparin (LMWH), warfarin, factor Xa inhibitors (XaI), and fondaparinux. Postoperative complications, including VTE, blood transfusion, myocardial infarction, and hematoma, were identified using ICD-9 diagnosis codes. Risk of each complication was compared between groups using multivariate logistic regression controlling for demographics, length of stay, and comorbidities.

RESULTS: Of 30,813 patients, 1.82% were diagnosed with VTE. Using ASA as a baseline, there was significantly decreased risk of VTE with LMWH (OR 0.47), XaI (OR 0.50), and fondaparinux (OR 0.32). There was significantly higher risk of transfusion with LMWH (OR 1.56) and fondaparinux (OR 1.84), but no difference in hematoma between medications.

CONCLUSIONS: This study shows that there is a decreased risk of VTE with LMWH, XaI, and fondaparinux compared to ASA. However, these medications also had higher rates of bleeding-associated complications. The choice of pharmacologic prophylaxis should be made based on a balance of the risk/benefit profile of each medication.

LEVEL OF EVIDENCE: III.