What are the American Academy of Orthopaedic Surgeons (AAOS) guidelines for Deep Vein Thrombosis (DVT) prophylaxis in patients undergoing arthroplasty?

AAOS Guidelines on DVT Prophylaxis in Arthroplasty

The American Academy of Orthopaedic Surgeons (AAOS) guidelines differ fundamentally from the American College of Chest Physicians (ACCP) recommendations, with AAOS rejecting asymptomatic DVT as a valid outcome and focusing only on symptomatic PE and fatal PE, while ACCP provides more comprehensive evidence-based recommendations for pharmacologic prophylaxis in major orthopedic surgery. 1

Critical Divergence Between Guidelines

The AAOS and ACCP guidelines reached very different conclusions despite having access to the same clinical trial data 1. The key disagreement centers on:

• AAOS position: Rejected DVT (both asymptomatic and symptomatic) as a valid outcome, considering the link between DVT and PE in hip or knee surgery patients to be unproven 1
• ACCP position: Accepted asymptomatic and symptomatic DVT detected by venography as valid measures of thromboprophylaxis efficacy, based on consistent associations between DVT and PE demonstrated in imaging studies and randomized controlled trials 1

The AAOS limited their analysis to studies reporting only symptomatic PE and fatal PE, while ACCP included objectively diagnosed DVT as a primary efficacy outcome 1.

ACCP Evidence-Based Recommendations (Most Comprehensive)

Standard-Risk Patients

For patients undergoing major orthopedic surgery (hip or knee arthroplasty), multiple pharmacologic options are recommended with Grade 1B evidence 1:

• Low-molecular-weight heparin (LMWH) - preferred agent, with first dose given at least 12 hours from surgery (either pre- or postoperatively) 1
• Fondaparinux 1
• Apixaban 1
• Dabigatran 1
• Rivaroxaban (FDA-approved for VTE prophylaxis in orthopedic surgery) 1
• Adjusted-dose vitamin K antagonist 1
• Low-dose unfractionated heparin 1
• Aspirin 1

Duration of Prophylaxis

Extended thromboprophylaxis for up to 35 days from the day of surgery is recommended rather than only 10-14 days (Grade 2B) 1. A minimum duration of 10-14 days is required, with consideration of extending to 35 days for patients at higher VTE risk 1.

Dual Prophylaxis Strategy

Dual prophylaxis combining an antithrombotic agent with intermittent pneumatic compression devices (IPCD) during hospital stay is recommended (Grade 2C) 1. Key specifications include:

• Use only portable, battery-powered IPCDs capable of recording and reporting proper wear time 1
• Target 18 hours of daily compliance for both inpatients and outpatients 1

High Bleeding Risk Patients

For patients with increased bleeding risk, use IPCD or no prophylaxis rather than pharmacologic treatment (Grade 2C) 1. Once bleeding risk diminishes, pharmacologic prophylaxis should be substituted for or added to mechanical methods 1.

Patient Compliance Considerations

For patients who decline or are uncooperative with injections or IPCD, use apixaban or dabigatran (alternatively rivaroxaban or adjusted-dose VKA if unavailable) rather than alternative forms of prophylaxis (Grade 1B) 1. This recommendation addresses the 13-37% nonadherence rate with LMWH or fondaparinux due to the burden of self-injection 1.

Contraindicated Interventions

IVC Filter Placement

IVC filter placement for primary prevention is recommended against in patients with increased bleeding risk or contraindications to both pharmacologic and mechanical prophylaxis (Grade 2C) 1. The evidence shows:

• No randomized trials support IVC filter use for primary prevention 1
• Documented harms in 2-6% of patients including DVT at insertion site, IVC occlusion, and filter migration 1
• Less than half of retrievable filters were removed at 6 months 1
• Complications during removal including carotid artery puncture and filter limb migration to right atrium and lung 1

Routine Screening Before Discharge

Routine screening for asymptomatic DVT before hospital discharge is not recommended 1. Studies failed to demonstrate benefit, with one patient developing major bleeding after treatment for asymptomatic DVT detected on screening 1.

Common Pitfalls to Avoid

• Do not extrapolate major orthopedic surgery guidelines to lower-risk procedures: Isolated ankle fractures and upper extremity procedures have fundamentally different risk profiles and do not require routine prophylaxis 2, 3
• Do not use aspirin alone as sole prophylaxis in high-risk patients: While aspirin is included as an option, more potent anticoagulation is preferred for standard major orthopedic surgery 1
• Do not discontinue prophylaxis at hospital discharge: Extended prophylaxis up to 35 days significantly reduces VTE events 1
• Do not ignore patient compliance factors: Injectable medications have high nonadherence rates; oral agents should be considered when compliance is a concern 1
• Do not use non-portable or non-recording IPCDs: Only battery-powered devices with compliance monitoring are recommended 1

Efficacy and Safety Data

LMWH and fondaparinux achieve residual clot rates <5% after total hip arthroplasty and 20% after total knee arthroplasty, but major bleeding occurs in 3-5% of patients 4. Newer Xa and thrombin inhibitors show greater efficacy with equal or higher bleeding rates 4. Low-intensity warfarin combines safety (bleeding rates <1%) with efficacy (readmission for clinical DVT or PE 0.2%) 4.