DVT Prophylaxis 2 Weeks After Hip Fracture Pinning
At 2 weeks post-hip fracture surgery, you should continue pharmacological DVT prophylaxis with LMWH (enoxaparin 40 mg subcutaneously once daily) or fondaparinux (2.5 mg subcutaneously once daily) for a total duration of 4-5 weeks (28-35 days) from the time of surgery. 1, 2
Duration of Prophylaxis
The critical evidence demonstrates that stopping prophylaxis at 7-10 days is insufficient:
- Extended prophylaxis up to 35 days total is strongly recommended for all hip fracture patients, as the VTE risk persists well beyond hospital discharge 1
- The SAVE-HIP3 trial showed that extended prophylaxis (approximately 30 days total) reduced VTE or all-cause mortality from 18.6% to 3.9% compared to stopping at 7-10 days (OR 0.18,95% CI 0.07-0.45, P<0.001) 1
- Extended prophylaxis with fondaparinux for up to 24 additional days after the initial perioperative period (total 32 days) was administered in clinical trials and is FDA-approved 2
- The risk of DVT remains significant (12-37%) when prophylaxis is discontinued early, particularly as patients continue rehabilitation with limited mobility 3
Preferred Pharmacological Agents at 2 Weeks
LMWH (Low Molecular Weight Heparin):
- Enoxaparin 40 mg subcutaneously once daily is the most widely used regimen 4, 5
- Should have been initiated before surgery if delayed, or as soon as hemostasis was established postoperatively 3, 1
Fondaparinux:
- 2.5 mg subcutaneously once daily 2, 6
- FDA-approved specifically for extended prophylaxis in hip fracture surgery 2
- Demonstrated 96% reduction in DVT risk and 89% reduction in symptomatic VTE with extended (4-week) versus perioperative (1-week) prophylaxis 6
- More cost-effective and efficacious than LMWH in hip fracture patients 7, 8
High-Risk Features Requiring Extended Prophylaxis
All hip fracture patients should be considered high-risk, but pay particular attention to: 1
- Age >75 years
- History of previous VTE
- Active cancer
- Limited mobility or prolonged immobilization
- Prolonged ICU or hospital length of stay
Renal Function Considerations
Critical dosing adjustments at 2 weeks:
- If creatinine clearance <30 mL/min: Avoid LMWH and fondaparinux; use unfractionated heparin 5000 U subcutaneously every 8 hours 3, 4
- If creatinine clearance 30-50 mL/min: Reduce fondaparinux to 1.5 mg daily 9; use LMWH with caution 3
- Fondaparinux is contraindicated in severe renal insufficiency (CrCl <30 mL/min) 3, 2
Mechanical Prophylaxis Adjuncts
Continue mechanical prophylaxis alongside pharmacological agents: 1, 4
- Intermittent pneumatic compression (IPC) devices provide additional efficacy
- Goal of 18 hours daily use 9
- Early ambulation should be encouraged as tolerated
Common Pitfalls to Avoid
Do not stop prophylaxis prematurely at 7-10 days - this is the most common error, as the VTE risk extends for 2 months post-surgery 3, 1
Do not use aspirin as sole therapy - ACCP explicitly recommends against this, as it provides suboptimal protection compared to other agents 3, 1, 7
Do not ignore renal function - failure to adjust for renal impairment leads to bleeding complications, particularly with renally-cleared agents 1
Do not administer doses too early postoperatively - fondaparinux must be given no earlier than 6-8 hours after surgery to minimize major bleeding risk 2
Bleeding Risk Monitoring
- Major bleeding with LMWH occurs in approximately 1.0-1.4% of hip fracture patients 1
- Monitor for signs of bleeding, particularly in elderly patients with renal impairment 3
- If active bleeding develops, temporarily hold anticoagulation and use mechanical prophylaxis until bleeding risk diminishes 4
When to Stop Prophylaxis
Continue prophylaxis until: 1, 2
- Minimum 28-35 days total from surgery have elapsed
- Patient is fully ambulatory
- No ongoing high-risk features are present