What is the recommended prophylaxis for preventing Deep Vein Thrombosis (DVT) or stroke after hip surgery?

VTE Prophylaxis After Hip Surgery

For patients undergoing hip surgery (hip replacement, hip fracture surgery), use low-molecular-weight heparin (LMWH) as first-line prophylaxis, specifically enoxaparin 40 mg subcutaneously once daily or 30 mg twice daily, initiated 12 hours before or after surgery and continued for a minimum of 10-14 days, with extended prophylaxis up to 35 days for high-risk patients. 1, 2

Primary Pharmacologic Recommendations

LMWH as Preferred Agent

• LMWH is the preferred first-line agent over all alternatives including fondaparinux, rivaroxaban, dabigatran, apixaban, warfarin, unfractionated heparin, and aspirin for both total hip arthroplasty (THA) and hip fracture surgery (HFS). 1
• Enoxaparin 40 mg once daily or 30 mg twice daily subcutaneously represents the most extensively studied and effective regimen. 2, 3, 4
• LMWH demonstrates superior efficacy compared to unfractionated heparin, with proximal DVT rates of 7.5% versus 18.5% (p=0.014) and significantly fewer bleeding complications. 5

Timing of Initiation

• Start LMWH 12 hours before surgery or 12 hours after surgery to balance efficacy with bleeding risk. 1, 2
• The majority of efficacy trials administered LMWH either 12 hours preoperatively or 2 hours preoperatively, with postoperative initiation showing possibly lower bleeding risk. 1, 3
• For hip fracture patients where surgery may be delayed, initiate LMWH from the time of admission. 1, 6

Alternative Pharmacologic Agents

Fondaparinux

• Fondaparinux 2.5 mg subcutaneously once daily is an effective alternative to LMWH, with VTE rates of 8.3% versus 19.1% for enoxaparin in hip fracture surgery (relative risk reduction 56%, p<0.001). 1, 7
• Initiate 6-8 hours after surgery once hemostasis is established. 2, 7
• Reduce dose to 1.5 mg daily for patients with creatinine clearance 30-50 mL/min; avoid if CrCl <30 mL/min. 2, 8
• Major bleeding occurred in 2.2% with fondaparinux versus 2.3% with enoxaparin in hip fracture surgery. 7

Oral Anticoagulants

• Rivaroxaban, apixaban, and dabigatran are acceptable alternatives but lack the extensive safety data of LMWH. 1
• Rivaroxaban should be initiated 6-10 hours after surgery once hemostasis is achieved. 2, 9
• Adjusted-dose warfarin (INR 2.0-3.0) is an option but has higher bleeding rates (5.5% versus 1.4% with LMWH, p=0.001) and logistical challenges. 1, 10

Unfractionated Heparin

• Low-dose unfractionated heparin (LDUH) 5000 units subcutaneously twice or three times daily can be used when LMWH is contraindicated. 1, 8
• LDUH is less effective than LMWH, with higher rates of both thrombosis and bleeding complications. 4, 5

Aspirin

• Aspirin as sole prophylaxis is NOT recommended for routine use after hip surgery, as it is less effective than other pharmacologic agents. 1

Duration of Prophylaxis

Standard Duration

• Minimum 10-14 days of prophylaxis is required for all patients undergoing hip surgery. 1, 2
• Continue prophylaxis throughout hospitalization and into the outpatient period. 2, 8

Extended Duration

• Extended prophylaxis up to 35 days (4 weeks post-surgery) is strongly recommended for high-risk patients including those with cancer, restricted mobility, obesity, or history of VTE. 1, 2, 8
• For hip fracture surgery, extended prophylaxis with fondaparinux for 21±2 days reduced VTE from 35.0% to 1.4% (relative risk reduction 95.9%, p<0.0001) compared to placebo. 7
• Extended LMWH prophylaxis is safer than oral anticoagulants, with major bleeding rates of 1.4% versus 5.5% (p=0.001). 10

Mechanical Prophylaxis

Intermittent Pneumatic Compression (IPC)

• Add IPC devices to pharmacologic prophylaxis for high-risk patients, targeting at least 18 hours of daily use. 1, 2, 8
• IPC alone can be used when pharmacologic prophylaxis is contraindicated due to high bleeding risk, though it is less effective than combined therapy. 1
• IPC plus LMWH reduces major bleeding by 10 fewer events per 1,000 patients compared to LMWH alone (from 26 to 16 per 1,000). 1

Elastic Stockings

• Elastic stockings (18-23 mm Hg at ankle) can be added to pharmacologic prophylaxis, with thigh-high preferred over calf-high. 1

Special Populations and Dose Adjustments

Renal Impairment

• For CrCl <30 mL/min: reduce enoxaparin to 30 mg once daily; avoid fondaparinux; consider unfractionated heparin or adjusted-dose warfarin. 2, 8
• For CrCl 30-50 mL/min with fondaparinux: reduce dose to 1.5 mg once daily. 2, 8

Obesity

• For patients >150 kg: increase enoxaparin to 40 mg subcutaneously every 12 hours rather than once daily dosing. 2, 8

High Bleeding Risk

• For patients with active bleeding or high bleeding risk, use mechanical prophylaxis with IPC alone until bleeding risk diminishes, then add pharmacologic prophylaxis. 1, 8
• Absolute contraindications to pharmacologic prophylaxis include active bleeding, severe thrombocytopenia (platelets <50,000/μL), and recent neurosurgery. 8

Cancer Patients

• Cancer patients undergoing hip surgery should receive extended LMWH prophylaxis for 4 weeks. 1, 2, 8

Neuraxial Anesthesia Considerations

Critical Timing

• For patients receiving epidural or spinal anesthesia, hold enoxaparin for 24 hours before catheter manipulation and resume no earlier than 2 hours after catheter removal to prevent epidural hematoma. 2
• Epidural or spinal hematomas can result in permanent paralysis; monitor patients frequently for neurological impairment. 9

Common Pitfalls and Caveats

Inadequate Prophylaxis

• Approximately 42-58% of at-risk patients do not receive appropriate VTE prophylaxis despite clear guidelines, representing a major quality gap. 2
• Every institution should have a formal written policy for VTE prevention in surgical patients. 1

Premature Discontinuation

• Premature discontinuation of anticoagulation increases thrombotic risk; consider coverage with another anticoagulant if stopping for reasons other than bleeding or completion of therapy. 9

IPC Adherence

• IPC adherence is often suboptimal and should be actively monitored; portable battery-powered devices with recording capability facilitate monitoring. 1

IVC Filters

• IVC filters should NOT be used for primary VTE prevention in hip surgery patients, even in high-risk scenarios. 1

Surveillance Ultrasound

• Routine surveillance with venous compression ultrasonography should NOT be performed in asymptomatic patients. 1