What is the recommended prophylaxis for Venous Thromboembolism (VTE) post hip surgery?

VTE Prophylaxis Following Hip Surgery

Low molecular weight heparin (LMWH) is the recommended first-line prophylaxis for venous thromboembolism (VTE) following hip surgery, starting 2-12 hours preoperatively and continuing for at least 7-10 days, with extended prophylaxis for 4 weeks recommended in high-risk patients. 1

Recommended Pharmacological Options

First-Line: LMWH

• Enoxaparin: 40 mg subcutaneously once daily 2, 1
• Dalteparin: 5,000 IU subcutaneously once daily 2, 1
• Advantages over unfractionated heparin:
  • Once-daily administration
  • More predictable pharmacokinetics
  • Lower risk of heparin-induced thrombocytopenia 1

Alternative Options

• Unfractionated heparin (UFH): 5,000 units subcutaneously three times daily 2
  • Consider in patients with severe renal impairment (CrCl <30 mL/min) 1
• Fondaparinux: 2.5 mg subcutaneously once daily 2
  • Start 6-8 hours after surgery
  • Contraindicated in patients with CrCl <30 mL/min 3

Timing and Duration

1. Initiation: 2-12 hours preoperatively 1
2. Standard duration: Minimum 7-10 days postoperatively 2, 1
3. Extended prophylaxis: 4 weeks (28-35 days) for high-risk patients, particularly:
   • Patients undergoing major hip surgery 2
   • Patients with active cancer 2
   • Patients with restricted mobility or obesity 2, 1
   • Patients with history of VTE 1

Efficacy Comparison

• LMWH has demonstrated superior efficacy compared to placebo in preventing VTE following hip surgery 3
• In direct comparisons, LMWH (enoxaparin) showed a VTE rate of 14% compared to 23.2% with unfractionated heparin 4
• Extended prophylaxis with LMWH reduces VTE rates from 35% to 1.4% compared to placebo 3

Mechanical Prophylaxis

• Should not be used as monotherapy unless pharmacological methods are contraindicated due to active bleeding or high bleeding risk 2, 1
• Can be added to pharmacological prophylaxis for enhanced efficacy, especially in highest-risk patients 2, 1
• Options include:
  • Graduated compression stockings
  • Intermittent pneumatic compression devices

Special Considerations

Renal Impairment

• For patients with CrCl <30 mL/min:
  • Unfractionated heparin is preferred 1
  • Avoid fondaparinux 3
  • If using LMWH, consider dose reduction and anti-Xa monitoring 1

Regional Anesthesia

• If neuraxial anesthesia is planned, timing of LMWH should be adjusted to minimize bleeding risk 1
• Last preoperative dose should be given with adequate time before the procedure
• Postoperative dose should be delayed until hemostasis is assured

Active Bleeding Risk

• For patients with high bleeding risk:
  • Consider mechanical prophylaxis initially 2
  • Start pharmacological prophylaxis when bleeding risk decreases
  • Consider prophylactic inferior vena cava filter only if anticoagulation is absolutely contraindicated 2

Common Pitfalls to Avoid

1. Inadequate duration: Stopping prophylaxis too early (before 7-10 days) increases VTE risk
2. Missed high-risk patients: Failing to provide extended prophylaxis (4 weeks) to high-risk patients
3. Relying solely on mechanical methods: Using only compression devices when pharmacological prophylaxis is not contraindicated
4. Inappropriate dosing: Using insufficient doses of LMWH (e.g., enoxaparin 10 mg daily has been shown to be ineffective) 5
5. Delayed initiation: Starting prophylaxis too late after surgery increases VTE risk

By following these evidence-based recommendations, the risk of postoperative VTE following hip surgery can be significantly reduced while minimizing bleeding complications.