What is the recommended DVT (Deep Vein Thrombosis) prophylaxis for patients with a femoral neck fracture?

DVT Prophylaxis for Femoral Neck Fracture

Low molecular weight heparin (LMWH) is the recommended first-line DVT prophylaxis for patients with femoral neck fracture, with administration starting 12 hours before surgery or 12-24 hours after surgery and continuing for 10-14 days, with extension up to 35 days recommended for high-risk patients. 1

Risk Assessment and Timing

Patients with femoral neck fractures are at high risk for venous thromboembolism (VTE) due to:

• Advanced age (>65 years is a significant risk factor) 2
• Reduced mobility from the fracture
• Inflammatory state generated by trauma 2
• Surgical intervention

The risk of DVT in hip fracture patients without prophylaxis is approximately 37%, with clinical symptoms appearing in only 1-3% of cases 2, 1.

Pharmacological Prophylaxis Options

First-Line Option:

• LMWH (e.g., Enoxaparin):
  • Dosing: 40 mg subcutaneously once daily 1
  • Timing: Start 12 hours before surgery or 12-24 hours after surgery 1
  • Duration: 10-14 days standard, up to 35 days for extended prophylaxis 2, 1
  • For elderly patients (>65 years): Consider 30 mg every 12 hours 1
  • For patients with renal impairment (CrCl 30-50 mL/min): Consider dose adjustment 1

LMWH is preferred over unfractionated heparin due to:

• Lower incidence of DVT and PE
• Fewer bleeding complications
• Less frequent dosing requirements 1

Alternative Options:

1. Fondaparinux:

   • Dosing: 2.5 mg subcutaneously once daily 1, 3
   • Timing: Start 6-8 hours after surgery when hemostasis is established 3
   • Duration: 5-9 days standard, with extension up to 24 additional days 3
   • Contraindicated in severe renal impairment (CrCl <30 mL/min) 1, 3

2. Direct Oral Anticoagulants (DOACs):

   • Rivaroxaban: 10 mg once daily starting 6-10 hours after surgery 1
   • Apixaban: Has favorable bleeding profile compared to other anticoagulants 1

3. Unfractionated Heparin (UFH):

   • Dosing: 5000 U subcutaneously every 8 hours 1
   • Primary use: When LMWH is contraindicated or in patients with severe renal insufficiency 1

4. Aspirin:

   • May be effective in standard-risk ambulatory patients 4
   • However, the American College of Chest Physicians recommends DOACs over aspirin 1

Mechanical Prophylaxis

Mechanical prophylaxis should be used in conjunction with pharmacological prophylaxis for optimal protection 2, 1:

• Intermittent pneumatic compression devices (IPC) for a goal of 18 hours daily 2
• Thromboembolism stockings
• Early mobilization when possible

For patients with high bleeding risk, mechanical prophylaxis alone may be used initially until the risk of bleeding decreases 2, 1.

Special Considerations

Timing of Administration

• For patients undergoing neuraxial anesthesia: Administer LMWH between 18:00 and 20:00 to minimize the risk of bleeding related to neuraxial procedures 2
• Do not administer pharmacological prophylaxis earlier than 6 hours after surgery to reduce risk of major bleeding 3

Preoperative Prophylaxis

• Preoperative thromboprophylaxis can effectively reduce the risk of DVT before surgery 5
• The prevalence of preoperative DVT 48 hours after injury approaches the reported postoperative incidence 6

Extended Prophylaxis

• Extended prophylaxis (up to 35 days) is strongly recommended for hip fracture patients 2, 1
• The risk of VTE persists for up to 2 months following hip surgery 1

Renal Impairment

• For severe renal impairment (CrCl <30 mL/min): Avoid fondaparinux and consider UFH or reduced-dose LMWH 1

Implementation

Simple interventions such as reminder posters in prescribing areas can improve compliance with VTE prophylaxis guidelines 7.

The American Academy of Orthopaedic Surgeons has upgraded the strength of recommendation for VTE prophylaxis in elderly hip fracture patients from moderate to strong in their 2021 guidelines 2.