Can aspirin be given after Open Reduction Internal Fixation (ORIF) of the femur for Deep Vein Thrombosis (DVT) prophylaxis?

Aspirin for DVT Prophylaxis After Femur ORIF

Aspirin can be used for DVT prophylaxis after ORIF of the femur, as it has demonstrated effectiveness in preventing venous thromboembolism following major orthopedic procedures including hip fracture surgery, though it may be slightly less effective than oral anticoagulants like rivaroxaban or LMWH. 1, 2

Evidence Supporting Aspirin Use

Orthopedic Surgery Context

• Aspirin is specifically recommended for VTE prophylaxis in orthopedic procedures including hip fracture surgery (which femur ORIF falls under), with the American College of Chest Physicians noting it as an acceptable option when concomitant risk factors are present 1
• A multicenter study of 1,141 patients with femoral neck fractures undergoing hip arthroplasty found aspirin had a VTE rate of only 1.98% compared to 6.7% for other anticoagulants, demonstrating non-inferiority 2
• Low-dose aspirin (160 mg daily) reduces symptomatic DVT by 28% (RR 0.72) and fatal PE by 58% (RR 0.42) compared to placebo in orthopedic patients 1

Comparative Effectiveness

• Aspirin may be less effective than oral anticoagulants for preventing all VTE events (RR = 1.206,95% CI 1.053-1.383), meaning approximately 20% higher relative risk compared to agents like rivaroxaban or warfarin 3
• However, a large RCT of 3,424 patients showed aspirin was non-inferior to rivaroxaban for symptomatic VTE prevention after hip/knee arthroplasty (0.64% vs 0.70%, p<0.001 for non-inferiority) 4
• European guidelines state aspirin may be as effective as LMWH for prevention of DVT and PE after hip fracture surgery (Grade 1C) 5

Safety Profile Advantages

Bleeding Risk

• Aspirin demonstrates significantly lower bleeding complications compared to oral anticoagulants 1, 4, 5
• Minor bleeding events are reduced by 31.5% with aspirin (RR = 0.685) compared to oral anticoagulants 3
• Major bleeding rates are similar between aspirin (0.47%) and rivaroxaban (0.29%), with no statistically significant difference 4
• Aspirin is associated with lower rates of wound complications and oozing compared to anticoagulants 6

Practical Dosing Recommendations

Standard Regimen

• Typical dosing is aspirin 81-325 mg daily, with most contemporary studies using 81 mg daily for extended prophylaxis 1, 4
• Duration should be at least 30 days post-operatively for hip procedures 4
• Some protocols use higher doses (160 mg or 325 mg daily) based on older orthopedic literature 1

Combination Approach

• Consider initial prophylaxis with rivaroxaban 10 mg daily for 5 days post-operatively, then transition to aspirin 81 mg daily for extended prophylaxis (this was the protocol in the largest non-inferiority trial) 4

Important Caveats and Contraindications

When NOT to Use Aspirin Alone

• Patients with elevated PE risk specifically should receive more potent anticoagulation rather than aspirin alone 1
• Active bleeding is an absolute contraindication until bleeding is controlled 1
• High VTE risk combined with high bleeding risk warrants mechanical prophylaxis (intermittent pneumatic compression) instead of any pharmacologic agent 1, 7
• Patients already on dual antiplatelet therapy should use mechanical prophylaxis rather than adding anticoagulation due to excessive bleeding risk 7

Risk Stratification Considerations

• Aspirin appears less effective in total knee arthroplasty compared to hip procedures, so consider more potent anticoagulation for TKA 3
• If mechanical prophylaxis is NOT being used concurrently, the VTE risk with aspirin alone may be higher 3
• Follow-up periods ≤3 months show higher VTE rates with aspirin, suggesting need for vigilant monitoring 3

Clinical Bottom Line

For standard-risk ambulatory patients undergoing femur ORIF, aspirin 81 mg daily is an effective and safe option for DVT prophylaxis, offering the advantages of lower bleeding risk, ease of administration, and cost-effectiveness compared to LMWH or DOACs. 2, 6 However, for patients with multiple VTE risk factors or specifically elevated PE risk, more potent anticoagulation with LMWH or rivaroxaban should be strongly considered despite the increased bleeding risk 1, 3.