What is the recommended anticoagulation regimen after hip fracture surgery?

Anticoagulation Regimen After Hip Fracture Surgery

Low-molecular-weight heparin (LMWH) is the recommended first-line anticoagulation regimen after hip fracture surgery, with fondaparinux as an effective alternative. 1, 2

Recommended Pharmacological Options

• LMWH (enoxaparin) is the preferred first-line option for VTE prophylaxis after hip fracture surgery, with standard dosing of 40 mg subcutaneously once daily or 30 mg twice daily 3, 1
• Fondaparinux 2.5 mg subcutaneously once daily is an effective alternative, particularly for patients who cannot use LMWH 2, 4
• For patients with renal impairment (CrCl 30-50 mL/min), fondaparinux dose should be reduced to 1.5 mg daily 1
• Fondaparinux is contraindicated in patients with severe renal impairment (creatinine clearance <30 mL/min) 4
• Unfractionated heparin 5000 U subcutaneously every 8-12 hours can be used when LMWH is contraindicated or in patients with renal failure 3, 2
• Warfarin (target INR 2.0-3.0) is an option but has been shown to be less effective than LMWH for hip fracture patients 1, 5

Timing of Initiation

• For LMWH, initiation should occur 12-24 hours after surgery once adequate hemostasis has been established 6
• For fondaparinux, the initial dose should be given no earlier than 6-8 hours after surgery once hemostasis is established 4
• If neuraxial anesthesia (epidural) was used, prophylactic doses of LMWH should not be administered within 10-12 hours before epidural catheter removal 3, 6
• The first dose of prophylactic LMWH can be administered no earlier than 2 hours after epidural catheter removal 6

Duration of Prophylaxis

• Extended prophylaxis of 28-35 days (4 weeks) is strongly recommended for hip fracture patients due to their high risk of venous thromboembolism 1, 6
• At minimum, thromboprophylaxis should be continued for 10-14 days for all patients undergoing hip fracture surgery 1, 6
• Extended prophylaxis has been shown to significantly reduce VTE risk compared to shorter duration regimens 1, 4

Mechanical Prophylaxis

• Intermittent pneumatic compression (IPC) devices should be used in addition to pharmacological prophylaxis for a goal of 18 hours daily 1
• For patients at high risk of bleeding, mechanical prophylaxis with IPC may be used alone until bleeding risk diminishes 1, 2
• Early ambulation should be encouraged as part of a multimodal approach to VTE prevention 1

Special Considerations

• For patients with severe renal impairment (creatinine clearance <30 mL/min), unfractionated heparin is preferred over LMWH or fondaparinux 2, 4
• Patients taking aspirin may have this withheld during inpatient stay unless indicated for unstable angina or recent/frequent transient ischemic attacks 3
• For patients on clopidogrel, surgery should not be delayed, but marginally greater blood loss should be expected 3
• For patients on warfarin, the INR should be <2 for surgery and <1.5 for neuraxial anesthesia 3

Comparative Efficacy

• LMWH has been shown to be more effective than unfractionated heparin in reducing the incidence of venous thrombosis (15.9% vs 21.7%) and proximal venous thrombosis (5.4% vs 12.5%) 3
• Fondaparinux has demonstrated effectiveness in hip fracture patients with thrombosis rates of 13% compared to 35% with dextran 3
• Patients prescribed warfarin after hip fractures have higher rates of DVT and PE compared to those prescribed LMWH 5

Common Pitfalls to Avoid

• Discontinuing prophylaxis too early (before 10-14 days) significantly increases the risk of venous thromboembolism 6
• Failure to extend prophylaxis beyond the hospital stay is a common error, as the risk of VTE remains elevated for several weeks after hip fracture surgery 6
• Starting anticoagulation too early after surgery, especially in patients who received neuraxial anesthesia, increases the risk of spinal hematoma 6
• Approximately 42-58% of at-risk patients do not receive appropriate VTE prophylaxis, despite clear guidelines 1