When should aspirin be discontinued before knee surgery?

When to Discontinue Aspirin Before Knee Surgery

For elective knee surgery, aspirin should be discontinued 3 days before the procedure (last intake on Day -3), though emerging evidence suggests continuation may be safe and potentially beneficial for total knee arthroplasty. 1

Guideline-Based Recommendations

Standard Discontinuation Protocol

The French Working Group on Perioperative Haemostasis provides clear timing for aspirin cessation:

• Last aspirin intake should occur 3 days before surgery (Day -3) for most orthopedic procedures 1
• For intracranial neurosurgery specifically, extend this to 5 days preoperatively 1
• Do not bridge with heparin (UFH or LMWH) or NSAIDs during the discontinuation period 1

Type of Knee Surgery Matters

For simple knee arthroscopy:

• Thromboprophylaxis (including aspirin) is only needed when additional risk factors are present 1
• Simple arthroscopy carries low thrombotic risk (9% asymptomatic DVT, 3% proximal DVT) 1

For total knee arthroplasty (TKA):

• Multiple guidelines support aspirin as sole thromboprophylaxis, including AAOS, SIGN, and Brazilian guidelines 1
• The rationale: aspirin causes less bleeding while providing adequate VTE prevention 1

Emerging Evidence Supporting Continuation

Recent High-Quality Data

The most recent large-scale evidence challenges routine discontinuation:

• A 2024 study of 126,692 TKA patients showed aspirin continuation is safe across all VTE risk profiles 2
• Patients receiving low-dose aspirin (81 mg) had decreased odds of DVT, PE, bleeding, infections, and hospitalizations compared to other anticoagulants 2
• A 2023 meta-analysis of 163,983 patients demonstrated aspirin is non-inferior to other anticoagulants for preventing thromboembolic events (OR 0.93 for DVT, OR 0.89 for PE) 3

Comparative Safety Data

A 2016 study directly comparing continuation versus discontinuation found:

• Blood loss and local bleeding complications were comparable between groups 4
• TKA patients continuing aspirin had more transient knee swelling (81.3% vs 35.1%) but no difference in orthopedic outcomes 4
• Trend toward fewer cardiac complications with continuation (0% vs 6.5%, p=0.107) 4

Clinical Decision Algorithm

For Total Knee Arthroplasty:

Low cardiovascular risk patients:

• Consider continuation of low-dose aspirin (81-100 mg) through surgery 4, 2
• If discontinuing, stop 3 days preoperatively 1

High cardiovascular risk patients (prior MI, stent, stroke):

• Strongly favor continuation given thrombotic risk outweighs bleeding risk 4, 2
• The POISE-2 trial excluded high-risk patients, so discontinuation data doesn't apply to this population 1

For Knee Arthroscopy:

• Continue aspirin unless extensive procedure (ACL reconstruction, tibial plateau repair) 1
• For complex arthroscopy, follow TKA guidelines above

Critical Caveats

Cardiovascular event risk with discontinuation:

• Stopping antiplatelet therapy increases stroke/cardiovascular events by approximately 2% within 30 days 1
• This risk persists even with brief interruptions 1

If discontinuation is chosen:

• Platelet function typically normalizes in 4-5 days (median 4 days) based on arachidonic acid aggregation testing 5
• The traditional 7-10 day window appears unnecessarily long 5

Dosing considerations:

• Do not reduce aspirin dosage preoperatively if taking up to 300 mg daily long-term 1
• Low-dose (81 mg) aspirin is the standard for VTE prophylaxis in arthroplasty 2