Abstract
Purpose:
Starting February 2012, our institution changed from enoxaparin (Lovenox) to the Factor Xa inhibitor, rivaroxaban (Xarelto) for venous thromboembolism prophylaxis after primary total hip (THA) and total knee arthroplasty (TKA). The purpose of our study was to compare rates of venous thromboembolism and rates of major bleeding between these two medications when used for venous thromboembolism prophylaxis after primary THA and TKA.
Methods:
A retrospective review was performed on 1795 patients who underwent THA or TKA at our institution between January 1, 2011 and December 31, 2012. Patients were excluded if they had a bilateral procedure, partial arthroplasty (hip hemiarthroplasty, unicompartmental knee arthroplasty), revision surgery, and cases designated as complex. Patients were excluded if they were on other anticoagulants (dabigatran, aspirin, clopidogrel, warfarin, heparin, fondaparinux), or if pre-operative creatinine was 1.2 or greater. After excluding these patients, there were 1089 patients included in the study. Chart review recorded demographics (age, gender), comorbidities (BMI, ASA, creatinine), surgery performed (primary THA or TKA), length of stay (LOS), venous thromboembolic events (deep venous thrombosis [DVT], pulmonary embolus [PE]), post-operative infections, and major bleeding events (stroke, post-operative bleeding requiring transfusion). Periprosthetic infection rates are also currently being reviewed. T-tests were used to compare continuous variables between treatment groups, and Chi-square tests were used to compare categorical variables between treatment groups (α = 0.05).
Results:
There were 779 patients (71.5%) who received enoxaparin and 310 patients (28.5%) who received rivaroxaban during the study period. Demographics of the patients are presented in Table 1. A comparison of venous thromboembolism rates
Pre-operative creatinine was higher in the enoxaparin group (0.81 ± 0.19 vs. 0.72 ± 0.18, p < 0.001). With the numbers available for study, there were no demonstrable differences in DVT (p = 0.400, power = 0.125), PE (p = 0.679, power = 0.066), cerebrovascular events (p = 0.913, power = 0.049), or transfusion rates (p = 0.412, power = 0.121).
Conclusion:
To our knowledge this is one of, if not the largest non-industry funded studies comparing these two medications. There were no statistically demonstrable differences between the enoxaparin and rivaroxaban groups in terms of venous thromboembolism or major bleeding complications.
