What are the recommendations for deep vein thrombosis (DVT) prophylaxis in patients undergoing hip and knee replacement surgeries?

DVT Prophylaxis for Hip and Knee Replacement Surgery

For patients undergoing hip or knee replacement surgery, use low molecular weight heparin (LMWH) or fondaparinux as first-line pharmacological prophylaxis, starting 12-24 hours postoperatively, and extend prophylaxis for up to 35 days after hip replacement and 10-14 days after knee replacement. 1

Preferred Pharmacological Agents

First-Line Options

• LMWH is the most intensively studied and preferred thromboprophylactic agent for both hip and knee replacement surgery 1, 2
• Fondaparinux (2.5 mg subcutaneously once daily) is considered an equal alternative to LMWH according to all major guidelines developed from 2006 onward 1, 2
• Rivaroxaban (10 mg once daily orally) is FDA-approved for VTE prevention after hip or knee arthroplasty and offers the advantage of oral administration without INR monitoring 1, 3
• Apixaban (2.5 mg twice daily orally) demonstrated superiority to enoxaparin in hip replacement (1.4% vs 3.9% VTE, RR 0.36, P<0.001) and was approved in Europe for this indication 1

Alternative Options

• Adjusted-dose warfarin (target INR 2.0-3.0) is acceptable but less preferred due to logistic difficulties, higher bleeding risk (3.3% vs 5.3% with LMWH), and lower efficacy compared to LMWH 1, 2
• Aspirin alone should NOT be used as sole prophylaxis as it is clearly less effective than other regimens and has never been evaluated in randomized trials for asymptomatic DVT prevention 1

Timing and Dosing

LMWH Administration

• Start LMWH 12-24 hours after surgery once hemostasis is established 1, 2
• Alternative timing: 12 hours before surgery, or 4-6 hours after surgery starting with half-dose then continuing with usual high-risk dose the following day 2
• Enoxaparin dosing: 30 mg every 12 hours or 40 mg once daily are both effective, with the twice-daily regimen showing 11% DVT rate vs 14% for once-daily dosing 4

Fondaparinux Administration

• Fondaparinux 2.5 mg subcutaneously once daily, starting no earlier than 6-8 hours after surgery once hemostasis is established 5
• Administration earlier than 6 hours postoperatively increases major bleeding risk 5

Direct Oral Anticoagulants

• Rivaroxaban 10 mg once daily, starting 6-10 hours postoperatively 3
• Apixaban 2.5 mg twice daily, starting 12-24 hours postoperatively 1

Duration of Prophylaxis

Hip Replacement

• Minimum duration: 10-14 days for all patients 1, 2
• Extended prophylaxis: Up to 35 days total is strongly recommended as the risk of DVT persists for 2-3 months postoperatively 1, 2, 6
• Extended prophylaxis reduces postdischarge VTE by approximately two-thirds (12-37% reduction in DVT) 2, 6
• Fondaparinux: 5-9 days standard, with up to 32 days studied in hip fracture surgery (including extended prophylaxis) 5

Knee Replacement

• Duration: 10-14 days is typically sufficient 1, 2
• Extended prophylaxis is less beneficial after knee replacement compared to hip replacement 6

Hip Fracture Surgery

• Extended prophylaxis course of up to 24 additional days beyond the initial 7-10 days is recommended 7, 5
• Total duration of up to 32 days has been studied in clinical trials 5

Mechanical Prophylaxis

Combination Therapy

• Intermittent pneumatic compression devices (IPCD) combined with pharmacological prophylaxis may further reduce VTE rates 1
• Use only portable, battery-powered IPCDs capable of recording daily wear time, with efforts to achieve 18 hours of daily compliance 1
• Combined mechanical and pharmacological prophylaxis reduces DVT risk by 66% compared to either modality alone 7

Mechanical Prophylaxis Alone

• Reserve mechanical prophylaxis alone for patients with high bleeding risk or active contraindications to anticoagulation 1
• Elastic stockings or IPCDs should be used intraoperatively and postoperatively when pharmacological agents are contraindicated 7

Special Populations and Contraindications

High Bleeding Risk

• In patients with increased bleeding risk, use IPCD or no prophylaxis rather than pharmacologic treatment (Grade 2C) 1
• Continue mechanical prophylaxis until bleeding risk decreases, then transition to pharmacological agents 1

Renal Impairment

• Rivaroxaban: Avoid in severe renal impairment (CrCl <30 mL/min), use with caution in moderate impairment (CrCl 30-50 mL/min) 1
• Fondaparinux: Contraindicated in severe renal insufficiency (CrCl <30 mL/min), use with caution in moderate impairment 1
• LMWH: Use with caution in severe renal insufficiency, follow manufacturer specifications for dose adjustment 1

Body Weight Considerations

• Fondaparinux: Contraindicated for thromboprophylaxis in patients <50 kg undergoing orthopedic surgery 1
• LMWH: Use caution in patients <50 kg and in elderly patients due to limited data 1
• Morbidly obese patients (BMI ≥40 kg/m²): Consider hospitalization during UFH administration or develop institutional LMWH dosing algorithms 1

Patient Preference and Compliance

• For patients who decline injections or are uncooperative with IPCD, use apixaban or dabigatran (alternatively rivaroxaban or adjusted-dose warfarin) rather than alternative prophylaxis (Grade 1B) 1
• Nonadherence rates of 13-37% occur with LMWH or fondaparinux in the outpatient setting, making oral agents attractive alternatives 1

Critical Contraindications

Neuraxial Anesthesia

• Epidural or spinal hematomas may occur in anticoagulated patients receiving neuraxial anesthesia or undergoing spinal puncture 3, 5
• Monitor patients frequently for neurological impairment and treat urgently if observed 3, 5
• Optimal timing between fondaparinux administration and neuraxial procedures is not known 5

Active Bleeding

• Delay pharmacological prophylaxis in patients with active bleeding, coagulopathy, or hemodynamic instability until stabilization occurs 7
• Use mechanical prophylaxis alone until pharmacological agents can be safely initiated 7

Common Pitfalls to Avoid

• Do not use aspirin as sole prophylaxis – it is explicitly recommended against by ACCP and French guidelines 1
• Do not stop prophylaxis at hospital discharge – extended prophylaxis significantly reduces postdischarge VTE, particularly after hip replacement 1, 2, 6
• Do not administer fondaparinux earlier than 6 hours postoperatively – this significantly increases major bleeding risk 5
• Do not use prophylactic IVC filters – no randomized trials support their use in primary prevention 1
• Do not forget to adjust for renal function – failure to do so can lead to bleeding complications with renally-cleared agents 2
• Do not rely on mechanical prophylaxis alone except when pharmacological agents are contraindicated – the level of evidence for mechanical devices alone is lower than for pharmacological prophylaxis 1, 7