What is the recommended anticoagulation therapy after femur (thigh bone) fracture repair?

From the Guidelines

Anticoagulation after femur fracture repair is strongly recommended for all patients to prevent venous thromboembolism (VTE), with low molecular weight heparin (LMWH) such as enoxaparin 40mg subcutaneously once daily being the preferred agent, starting 12-24 hours after surgery and continuing for 28-35 days for hip fractures. The use of LMWH has been shown to reduce the risk of VTE in patients undergoing major orthopedic surgery, including hip fracture repair 1.

The evidence suggests that extended prophylaxis is necessary, as the hypercoagulable state persists well beyond hospital discharge. The American College of Chest Physicians (ACCP) recommends that patients undergoing hip fracture surgery should receive LMWH starting before or as soon as possible after surgery, and continuing for a minimum of 7-10 days 1.

Alternatively, direct oral anticoagulants (DOACs) like rivaroxaban 10mg daily or apixaban 2.5mg twice daily can be used. For patients with renal impairment, dose adjustments are necessary; with severe renal failure, unfractionated heparin may be preferred. Mechanical prophylaxis with intermittent pneumatic compression devices should be used until the patient is ambulatory, especially if anticoagulation is contraindicated.

Some key points to consider when managing anticoagulation after femur fracture repair include:

• Early mobilization should complement pharmacological prophylaxis
• Patients should be monitored for signs of bleeding complications and educated about symptoms of deep vein thrombosis or pulmonary embolism
• The high risk of VTE after femur fracture repair (up to 60% without prophylaxis) justifies extended prophylaxis
• Fondaparinux or low molecular weight heparins are commonly prescribed and may impact on the anaesthetic technique 1.

Overall, the goal of anticoagulation after femur fracture repair is to prevent VTE while minimizing the risk of bleeding complications. By using LMWH or DOACs, and combining pharmacological prophylaxis with mechanical prophylaxis and early mobilization, patients can reduce their risk of VTE and improve their outcomes.

From the FDA Drug Label

The rates of major bleeding events reported during 3 active-controlled peri-operative VTE prophylaxis trials with enoxaparin sodium in hip fracture, hip replacement, or knee replacement surgery (N = 3,616) and in an extended VTE prophylaxis trial (n = 327) with fondaparinux sodium 2.5 mg are provided in Table 2. In this analysis, the incidences of major bleeding were as follows: <4 hours was 4.8% (5/104), 4 to 6 hours was 2.3% (28/1,196), 6 to 8 hours was 1.9% (38/1,965).

The fondaparinux sodium drug label provides information on the rates of major bleeding events in patients undergoing hip fracture repair.

• Major bleeding rates for fondaparinux sodium 2.5 mg were 2.7% in the peri-operative prophylaxis trials and 2.4% in the extended prophylaxis trial.
• Timing of major bleeding events: the majority (≥75%) occurred during the first 4 days after surgery.
• Hip fracture specifically: major bleeding rate was 2.2% for fondaparinux sodium 2.5 mg. Based on this information, anticoagulation with fondaparinux sodium after femur fracture repair may be associated with a risk of major bleeding, particularly in the first 4 days after surgery 2.

From the Research

Anticoagulation after Femur Fracture Repair

• The use of anticoagulation therapy after femur fracture repair is a common practice to prevent venous thromboembolism (VTE) 3, 4.
• A study published in The New England Journal of Medicine found that aspirin was noninferior to low-molecular-weight heparin in preventing death and was associated with low incidences of deep-vein thrombosis and pulmonary embolism in patients with extremity fractures that had been treated operatively or with any pelvic or acetabular fracture 3.
• Another study published in Injury found that patients undergoing treatment with direct oral anticoagulants (DOAC) had a 3.4-fold increased risk for intraoperative blood transfusion, while patients taking aspirin, platelet aggregation inhibitors, or vitamin K antagonists did not differ from the control group in terms of transfusion rate 5.
• The timing of surgery is also an important consideration in patients with proximal femur fractures who are on anticoagulation therapy, with some studies suggesting that early surgical care is safe even in patients with anticoagulant medication 5, 6.
• The choice of anticoagulant therapy may also depend on the specific type of fracture and the patient's individual risk factors, with some studies suggesting that fondaparinux may be more effective than enoxaparin in preventing VTE in patients undergoing surgery for hip fracture 4.
• A systematic review and meta-analysis published in Annals of Internal Medicine found that oral direct factor Xa inhibitors were associated with a small absolute risk reduction in symptomatic deep venous thrombosis compared to low-molecular-weight heparin, but may increase major bleeding 7.

Types of Anticoagulation Therapy

• Aspirin: noninferior to low-molecular-weight heparin in preventing death and associated with low incidences of deep-vein thrombosis and pulmonary embolism 3.
• Low-molecular-weight heparin: commonly used for thromboprophylaxis in patients with fractures, but may be associated with an increased risk of bleeding 3, 7.
• Direct oral anticoagulants (DOAC): associated with an increased risk of intraoperative blood transfusion, but may be safe for use in patients with proximal femur fractures who are undergoing early surgical care 5.
• Fondaparinux: may be more effective than enoxaparin in preventing VTE in patients undergoing surgery for hip fracture 4.
• Vitamin K antagonists: may be associated with an increased risk of bleeding, but can be safely used in patients with proximal femur fractures who are undergoing early surgical care 5.