What is the recommended DVT (Deep Vein Thrombosis) prophylaxis for patients with hip fractures?

DVT Prophylaxis for Hip Fracture

All patients undergoing hip fracture surgery should receive pharmacological thromboprophylaxis with either fondaparinux 2.5 mg subcutaneously once daily or low molecular weight heparin (LMWH), initiated 6-8 hours after surgery once hemostasis is established, and continued for a minimum of 7-10 days with strong consideration for extended prophylaxis up to 28-35 days total. 1, 2, 3

Preferred Pharmacological Agents

First-Line Options

• Fondaparinux 2.5 mg subcutaneously once daily is recommended as the preferred agent, demonstrating cost-effectiveness and superior efficacy compared to LMWH 1, 3, 4
• LMWH (enoxaparin) 40 mg subcutaneously once daily is an equally effective alternative and may be preferred in certain clinical contexts 1, 2
• For elderly patients (>65 years), enoxaparin 30 mg every 12 hours is the recommended initial dose 5

LMWH Superior to Unfractionated Heparin

• LMWH demonstrates significantly lower rates of DVT (P=0.007), PE (P<0.001), bleeding complications, transfusions, and mortality (P<0.001) compared to unfractionated heparin in elderly trauma patients 5
• This superiority is particularly evident in patients with ISS <16 and those aged >75 years 5

Avoid Factor Xa Inhibitors as First-Line

• Factor Xa inhibitors show a higher rate of PE (AR 2 vs -3.5) compared to LMWH, making them suboptimal despite better patient compliance 5

Timing of Initiation

• Initiate prophylaxis no earlier than 6-8 hours after surgery once hemostasis has been established 1, 3
• Administration earlier than 6 hours significantly increases major bleeding risk 3
• Pre-operative prophylaxis does not reduce mortality or reoperation rates, though it may decrease intraoperative bleeding with certain fixation methods (hip compression screw but not intramedullary nail) 5

Duration of Prophylaxis

Minimum Duration: 7-10 Days

• All patients require at least 7-10 days of pharmacological prophylaxis postoperatively 1, 2, 3

Extended Prophylaxis: 28-35 Days Total

• Extended prophylaxis for up to 24-28 additional days (total 28-35 days) is strongly recommended for all hip fracture patients, as VTE risk persists well beyond hospital discharge 1, 2, 3
• Fondaparinux trials demonstrated up to 32 days total duration (peri-operative plus extended) 3
• Extended semuloparin prophylaxis (total ~30 days) reduced 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, 2

Adjunctive Mechanical Prophylaxis

• Thromboembolism stockings or intermittent pneumatic compression (IPC) devices should be employed intra-operatively and postoperatively in conjunction with pharmacological prophylaxis 5, 1
• Combined mechanical and pharmacological prophylaxis achieves a 66% reduction in DVT risk (RR 0.34) compared to either modality alone 5, 2
• Mechanical prophylaxis alone is insufficient and should not be used as sole therapy 1

Special Populations and Dose Adjustments

Renal Impairment

• In patients with renal failure, switch to unfractionated heparin 5000 units subcutaneously every 8 hours instead of LMWH 5, 2
• Dose adjustment according to anti-Xa levels may be warranted in elderly patients with renal impairment 5

Neuraxial Anesthesia Considerations

• LMWH timing must be carefully coordinated with neuraxial anesthesia to minimize bleeding risk 5, 1
• LMWH should be administered between 18:00-20:00 to minimize risk during daytime trauma lists 5

Critical Contraindications Requiring Delayed Prophylaxis

Delay pharmacological prophylaxis until stabilization occurs in patients with: 5, 2

• Active bleeding
• Coagulopathy
• Hemodynamic instability
• Solid organ injury
• Traumatic brain injury
• Spinal trauma

In these cases, use mechanical prophylaxis (intermittent pneumatic compression or elastic stockings) until pharmacological agents can be safely initiated 5

High-Risk Features Mandating Extended Prophylaxis

All hip fracture patients are inherently high-risk, but particular attention should be given to: 5, 2

• 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

Bleeding Risk and Monitoring

• Major bleeding with LMWH occurs in approximately 1.0-1.4% of hip fracture patients 2
• LMWH demonstrates fewer bleeding complications compared to unfractionated heparin (P<0.001) 5
• Regular assessment for signs and symptoms of DVT/PE is essential throughout the prophylaxis period 1

Common Pitfalls to Avoid

• Do not use aspirin as sole therapy for DVT prophylaxis—it provides suboptimal protection compared to other agents 2, 4
• Do not administer fondaparinux or LMWH earlier than 6 hours post-surgery due to bleeding risk 3
• Do not discontinue prophylaxis at hospital discharge—extend for total 28-35 days 1, 2
• Do not rely on mechanical prophylaxis alone except when pharmacological agents are contraindicated 5, 1