What is the recommended duration of anticoagulant (blood thinner) therapy after hip reduction and internal fixation?

From the Guidelines

Anticoagulation therapy after hip reduction and internal fixation is typically recommended for 28-35 days (4-5 weeks) postoperatively. The preferred medications include low molecular weight heparins (LMWHs) such as enoxaparin 40mg subcutaneously once daily or fondaparinux 2.5mg subcutaneously once daily. Alternatively, direct oral anticoagulants (DOACs) like rivaroxaban 10mg orally once daily or apixaban 2.5mg orally twice daily can be used, as supported by the RECORD trials which compared rivaroxaban with enoxaparin for VTE prophylaxis in patients undergoing hip replacement surgery 1. For patients with contraindications to these medications, aspirin 81-325mg orally daily may be considered, though it provides less effective prophylaxis.

Key Considerations

• Anticoagulation should begin either 12 hours postoperatively or the evening before surgery if using LMWHs, as guided by the management of direct oral anticoagulants in patients undergoing elective surgeries and invasive procedures 1.
• Early mobilization should complement pharmacological prophylaxis.
• This extended duration of anticoagulation is necessary because patients undergoing hip fracture surgery have a high risk of venous thromboembolism (VTE) that persists beyond hospital discharge.
• The risk remains elevated for several weeks due to limited mobility, surgical trauma, and the hypercoagulable state induced by surgery.
• Proper anticoagulation significantly reduces the risk of deep vein thrombosis and pulmonary embolism, which are potentially life-threatening complications following hip surgery.

Medication Selection

• Rivaroxaban has been shown to reduce DVT, PE, or death without increased bleeding rates in the RECORD trials 1.
• Apixaban has also been found to be effective in reducing recurrent VTE without increasing major bleeding, as seen in the AMPLIFY-EXTEND Investigators study 1.
• The choice of anticoagulant should be based on patient-specific factors, including renal function and the presence of any contraindications.
• Creatinine clearance should be monitored postoperatively if the invasive procedure and/or medical condition of the patient could affect renal function, and the dose regimen of DOA should be titrated accordingly 1.

From the FDA Drug Label

2.1 Recommended Dosage in Adults Table 1: Recommended Dosage in Adults IndicationRenal Considerations *DosageFood/Timing † ... Hip Replacement Surgery§ CrCl ≥15 mL/min ‡10 mg once daily for 35 days, 6–10 hours after surgery once hemostasis has been establishedTake with or without food CrCl <15 mL/minAvoid Use

The recommended duration of anticoagulant therapy after hip replacement surgery is 35 days 2.

From the Research

Recommended Duration of Anticoagulant Therapy

The recommended duration of anticoagulant therapy after hip reduction and internal fixation can vary depending on the specific circumstances of the patient and the type of surgery performed.

• According to 3, extended-duration prophylaxis (for 4 to 5 weeks) is recommended for patients undergoing hip arthroplasty or hip fracture repair.
• A study by 4 compared the efficacy and safety of aspirin and rivaroxaban following enoxaparin treatment for prevention of venous thromboembolism after hip fracture surgery, and found that extended prophylaxis for 21 days with aspirin was equivalent to the direct oral anticoagulant rivaroxaban.
• Another study by 5 found that an extended aspirin regimen was at least as effective as modified rivaroxaban for preventing clinically important venous thromboembolism among patients undergoing hip or knee arthroplasty.

Factors Influencing Duration of Anticoagulant Therapy

Several factors can influence the duration of anticoagulant therapy, including:

• Type of surgery: Hip fracture repair, hip arthroplasty, and knee arthroplasty may have different recommended durations of anticoagulant therapy 3, 5.
• Patient risk factors: History of venous thromboembolism is a significant risk factor for post-operative venous thromboembolism 5.
• Type of anticoagulant: Different anticoagulants, such as aspirin, enoxaparin, and rivaroxaban, may have different recommended durations of use 4, 5, 6.

Anticoagulant Options

Several anticoagulant options are available for preventing venous thromboembolism after hip reduction and internal fixation, including:

• Aspirin: Recommended for extended prophylaxis (up to 21 days) after hip fracture surgery 4 and for preventing clinically important venous thromboembolism among patients undergoing hip or knee arthroplasty 5.
• Enoxaparin: Recommended for extended-duration prophylaxis (for 4 to 5 weeks) after hip arthroplasty or hip fracture repair 3.
• Rivaroxaban: Compared to enoxaparin, rivaroxaban was associated with cost savings and prevented an average of 0.0145 symptomatic VTE events per patient in the THR population 7.