What is the normal dosage for anticoagulation following hemiarthroplasty of the hip?

Anticoagulation Dosing for VTE Prophylaxis Following Hip Hemiarthroplasty

For VTE prophylaxis after hip hemiarthroplasty, rivaroxaban 10 mg once daily for 35 days is the recommended first-line option, initiated 6-10 hours after surgery once hemostasis is established. 1

Primary Pharmacological Options

Rivaroxaban (Preferred)

• Dose: 10 mg orally once daily 2, 1
• Duration: 35 days for hip arthroplasty 2, 1
• Timing: Start 6-10 hours after surgery once hemostasis is achieved 1
• Administration: Can be taken with or without food 1
• Evidence: The RECORD trials demonstrated that rivaroxaban reduced DVT, PE, or death without increased bleeding rates compared to enoxaparin 2. Extended duration rivaroxaban (31-39 days) after hip arthroplasty was more effective than short-term enoxaparin (10-14 days) without increased bleeding complications 2, 3
• Contraindications: Avoid in patients with CrCl <15 mL/min 1, severe liver disease, hepatic coagulopathy, or severe renal insufficiency (CrCl <30 mL/min for VTE indication) 2

Low-Molecular-Weight Heparin (Alternative)

• Enoxaparin dose: 40 mg subcutaneously once daily OR 30 mg subcutaneously twice daily 2, 4
• Duration: Minimum 10-14 days, with extension up to 35 days recommended 4
• Timing: Start 12 hours before or after surgery 4
• Renal dosing: Reduce to 30 mg once daily if CrCl <30 mL/min 4
• Obesity dosing: Consider 40 mg every 12 hours for patients >150 kg 4

Apixaban (Alternative)

• Dose: 2.5 mg orally twice daily 2
• Duration: 35 days for hip arthroplasty 2
• Timing: Start 12-24 hours after surgery 2
• Evidence: The ADVANCE-3 trial showed apixaban was superior to enoxaparin (1.4% vs 3.9% VTE rate) with numerically lower bleeding rates 2

Fondaparinux (Alternative)

• Dose: 2.5 mg subcutaneously once daily 4
• Renal dosing: 1.5 mg daily for CrCl 30-50 mL/min 4
• Timing: Start 6-8 hours after surgery once hemostasis is established 4
• Contraindication: Avoid if CrCl <30 mL/min 4

Unfractionated Heparin (When LMWH Contraindicated)

• Dose: 5000 units subcutaneously twice or three times daily 4

Warfarin (Not Preferred)

• Target INR: 2.0-3.0 4
• Note: Not preferred over newer agents due to monitoring requirements and delayed onset 4

Duration Considerations

All patients require a minimum of 10-14 days of prophylaxis, with extended prophylaxis up to 35 days strongly recommended for hip arthroplasty. 4

• Standard duration: 10-14 days minimum 4
• Extended duration: Up to 35 days, especially for high VTE risk patients 4
• The RECORD 2 trial specifically demonstrated that extended rivaroxaban (31-39 days) was more effective than short-term enoxaparin without increased bleeding 2

Adjunctive Mechanical Prophylaxis

• Intermittent pneumatic compression (IPC): Use in addition to pharmacological prophylaxis for 18 hours daily 4
• High bleeding risk patients: Use mechanical prophylaxis alone until bleeding risk diminishes 4
• Early ambulation: Encourage as part of multimodal approach 4

Special Populations

Renal Impairment

• CrCl 30-50 mL/min: Rivaroxaban can be used at standard dose; reduce fondaparinux to 1.5 mg daily 4, 1
• CrCl 15-30 mL/min: Rivaroxaban expected to have similar concentrations as moderate renal impairment 1; reduce enoxaparin to 30 mg once daily 4
• CrCl <15 mL/min: Avoid rivaroxaban 1; consider unfractionated heparin or warfarin 4

High Bleeding Risk

• Use mechanical prophylaxis with IPC until bleeding risk diminishes, then add pharmacological prophylaxis 4
• Consider aspirin or IPC alone for patients who cannot use heparins 4

Cancer Patients

• Extend LMWH prophylaxis to 4 weeks 4

Critical Pitfalls to Avoid

• Underdosing duration: 42-58% of at-risk patients do not receive appropriate extended prophylaxis despite clear guidelines 4. Hip arthroplasty requires 35 days, not just the hospital stay duration.
• Timing errors: Starting rivaroxaban too early (before hemostasis) increases bleeding risk; starting too late reduces efficacy 1
• Ignoring renal function: Failure to adjust dosing for renal impairment can lead to drug accumulation and bleeding 4, 1
• Drug interactions: Potent CYP3A4 and P-glycoprotein inhibitors (ketoconazole, ritonavir) are contraindicated with rivaroxaban 2
• Neuraxial anesthesia: If epidural/spinal anesthesia used, hold enoxaparin 24 hours before catheter manipulation and resume no earlier than 2 hours after removal 4