What is the recommended DVT (Deep Vein Thrombosis) prophylaxis for a patient with a left femur fracture?

DVT Prophylaxis for Left Femur Fracture

For a patient with a left femur fracture, initiate pharmacological thromboprophylaxis with low-molecular-weight heparin (LMWH), specifically enoxaparin 30 mg subcutaneously every 12 hours, starting 12 hours before surgery if surgery is delayed, or as soon as hemostasis is established postoperatively (no earlier than 6-8 hours after surgery), and continue for a minimum of 7-10 days with strong consideration for extended prophylaxis up to 35 days. 1

Preferred Agent and Dosing

• Enoxaparin (LMWH) is the first-line agent for DVT prophylaxis in femur fractures, demonstrating superior efficacy compared to unfractionated heparin with lower rates of DVT, PE, bleeding complications, and mortality in trauma patients. 1

• Standard dosing is enoxaparin 30 mg subcutaneously every 12 hours for most patients. 2, 1

• For patients weighing >150 kg, increase the dose to 40 mg every 12 hours. 1

• For patients with renal impairment (CrCl <30 mL/min), reduce the dose to 30 mg once daily or switch to unfractionated heparin 5000 units every 8 hours. 1

• The 30 mg twice daily regimen has been validated specifically in orthopedic surgery and hip fracture patients, with studies showing 11% DVT incidence compared to 14% with 40 mg once daily dosing. 3

Timing of Initiation

• Start LMWH 12 hours before surgery if surgery is delayed, or as soon as hemostasis is established postoperatively. 2, 1

• Do not administer earlier than 6-8 hours after surgery as this significantly increases the risk of major bleeding. 4

• If active bleeding, coagulopathy, hemodynamic instability, traumatic brain injury, or spinal trauma is present, delay pharmacological prophylaxis and use mechanical prophylaxis instead until stabilization occurs. 2, 1

Duration of Prophylaxis

• Minimum duration is 7-10 days for all femur fracture patients. 2, 1

• Extended prophylaxis up to 35 days is strongly recommended for femur fractures, as the VTE risk persists well beyond hospital discharge. 2, 1

• Extended prophylaxis reduces VTE or all-cause mortality from 18.6% to 3.9% compared to stopping at 7-10 days (OR 0.18, P<0.001). 1

Adjunctive Mechanical Prophylaxis

• Combine pharmacological prophylaxis with intermittent pneumatic compression (IPC) devices to achieve a 66% reduction in DVT risk (RR 0.34). 1

• IPC devices should be used for a goal of 18 hours daily. 1

• Graduated compression stockings or antiembolism stockings are alternative mechanical options. 2

• Early mobilization should be encouraged as part of the prophylactic strategy. 2, 1

Alternative Agents When LMWH is Contraindicated

• Unfractionated heparin 5000 units subcutaneously every 8 hours is the preferred alternative when LMWH cannot be used. 2, 1

• Fondaparinux 2.5 mg subcutaneously once daily is another option, administered no earlier than 6-8 hours after surgery, continued for 7-10 days with consideration for up to 35 days. 2, 4

• Fondaparinux is contraindicated in patients with severe renal insufficiency (CrCl <30 mL/min) and should be used with caution in patients weighing <50 kg or with moderate renal impairment (CrCl 30-50 mL/min). 4

• Aspirin 81 mg twice daily is noninferior to LMWH for preventing death in extremity fractures (difference 0.05 percentage points, P<0.001 for noninferiority), though it was associated with a slightly higher incidence of DVT (2.51% vs 1.71%, difference 0.80 percentage points). 5 However, guidelines still prioritize LMWH as first-line therapy. 1

High-Risk Features Requiring Extended Prophylaxis

Femur fractures are inherently high-risk, but features that mandate extended prophylaxis up to 35 days include: 2, 1

• Age >75 years
• History of previous VTE
• Active cancer
• Limited mobility
• Prolonged ICU or hospital length of stay
• Severe traumatic brain injury or spine injury
• Mechanical ventilation

Critical Contraindications and Precautions

• Delay pharmacological prophylaxis in the presence of:

  • Active bleeding 2, 1
  • Coagulopathy 2, 1
  • Hemodynamic instability 2, 1
  • Traumatic brain injury 2, 1
  • Spinal trauma requiring neuraxial anesthesia 1

• For patients requiring neuraxial anesthesia, hold LMWH for 24 hours before catheter manipulation and resume no earlier than 2 hours after catheter removal. 1

• Epidural or spinal hematomas may occur in patients anticoagulated with LMWH who are receiving neuraxial anesthesia or undergoing spinal puncture, potentially resulting in long-term or permanent paralysis. 4

Monitoring and Dose Adjustment

• Dose adjustment according to anti-Xa levels and weight is warranted in elderly patients or those with renal impairment. 1

• Major bleeding with LMWH occurs in approximately 1.0-1.4% of patients, though studies in hip fracture surgery show rates of 4-5% with higher-dose regimens. 1, 3

• Monitor platelet counts for heparin-induced thrombocytopenia, particularly in patients with prior heparin exposure. 1

• Pre-operative prophylaxis in hip fracture patients did not influence mortality or risk of reoperation but decreased the risk of intraoperative bleeding complications for operations with hip compression screw. 2