Comparison of Surgical Site Infection Risk between Warfarin, Low Molecular Weight Heparin and Aspirin When Used for Venous Thromboprophylaxis Following Knee or Hip Arthroplasty- A Systematic Review and Meta-Analysis of 9 Studies Including 184,105 Cases

Aim: To compare the surgical site infection risk between Warfarin, Low Molecular Weight Heparin (LMWH) and Aspirin when used for venous thromboembolism (VTE) prophylaxis following total knee or hip arthroplasty. Methods: A systematic literature search was conducted on 27th November 2018 using PubMed, CINAHL and Cochrane Register of Controlled Trials (CENTRAL) databases to identify studies that compared warfarin, LMWH and/or aspirin in relation to surgical site infection rates following hip or knee arthroplasty. Meta-analyses were performed to compare the infection and VTE risk between groups. Results: 9 articles including 184,105 patients met the inclusion criteria. Meta-analysis showed that warfarin prophylaxis is associated with a higher risk of deep/reoperation (OR 1.929, 95% CI 1.197-3.109, P=0.007) and overall (OR 1.610, 95% CI 1.028-2.522, P=0.038) surgical site infection as compared to aspirin in primary total joint arthroplasty, with similar findings also seen with primary and revision procedures combined. There was no significant difference in infection risk between warfarin and LMWH and between LMWH and aspirin. There was a non-significant trend for VTE risk to be higher in warfarin compared to aspirin therapy for primary procedures (OR 1.6, 95% CI 0.875-2.926, P=0.127) and this was statistically significant when both primary and revision cases were included (OR=2.674, 95% CI 1.143-6.255, P=0.023). Conclusions: Warfarin is associated with a higher surgical site infection and VTE risk compared to aspirin. These findings caution the use of warfarin for VTE prophylaxis for hip and knee arthroplasty. Funding Statement: None. Declaration of Interests: None.