Venous Thromboembolism Prophylaxis after Orthopedic Surgery

Introduction to VTE Prophylaxis

The American College of Chest Physicians (ACCP) recommends low-molecular-weight heparin (LMWH) as the first-line option for VTE prophylaxis after orthopedic surgery, with apixaban being a superior alternative to aspirin when LMWH cannot be used 1
The American Academy of Orthopedic Surgeons (AAOS) considers aspirin a potential option, but the ACCP advises against aspirin as sole prophylaxis 2, 3

The recommended dosage of apixaban for VTE prophylaxis is 2.5 mg twice daily, starting 12-24 hours after surgery, and the duration of prophylaxis should be 35 days after hip replacement surgery and 14 days after knee replacement surgery 1, 4
Rivaroxaban can be used as an alternative to LMWH, with a dosage of 10 mg orally once daily 2
Apixaban dosing for different indications:

Indication	Apixaban Dosing
Atrial fibrillation	5 mg BID (or 2.5 mg BID if ≥2 criteria: age ≥80 years, weight ≤60 kg, or creatinine ≥133 μmol/L)
VTE treatment	10 mg BID for 7 days, then 5 mg BID

Apixaban is superior to enoxaparin (LMWH) in preventing VTE in hip replacement surgery, with a VTE incidence of 1.4% vs 3.9% 1
Apixaban is associated with lower rates of major bleeding compared to enoxaparin in clinical trials 1
Combining apixaban with aspirin or other medications that increase bleeding risk can significantly increase bleeding risk without providing additional protection against thromboembolism 1

Prophylaxis should be started 12-24 hours after surgery once hemostasis is established and continued for 10-14 days postoperatively 3, 6
The American Society of Regional Anesthesia and Pain Medicine recommends waiting a minimum of 6 hours after the end of the procedure and ensuring surgical hemostasis is achieved before initiating DOACs 4
For patients with CrCl <50 mL/min, apixaban and rivaroxaban are preferred over dabigatran, while for CrCl <15 mL/min, DOACs should be avoided 2, 7, 4
Ensure adequate renal function before initiating apixaban therapy, as dose adjustment may be needed if CrCl is 30-50 mL/min 4
Tinzaparin may be safer for patients with renal insufficiency 7

Patients with elevated bleeding risk should be considered for mechanical prophylaxis initially, then add pharmacological when safe, while those with normal renal function can use any first-line agent 3
Patients with compliance concerns may benefit from DOACs due to simpler regimens, while those with a history of GI bleeding may be considered for apixaban due to lower GI bleeding risk 2
Regular assessment of bleeding risk and monitoring of renal function postoperatively, especially in elderly patients, are crucial for the safe use of anticoagulants in orthopedic surgery 8

Intermittent pneumatic compression (IPC) should be used in addition to pharmacological prophylaxis for 18 hours daily, especially when pharmacological prophylaxis is contraindicated due to high bleeding risk 6, 8
Check for drug interactions, particularly P-glycoprotein inhibitors and CYP3A4 inhibitors, which can affect apixaban metabolism 1
Common errors include premature initiation of DOACs before adequate hemostasis, inappropriate dosing, inadequate duration of prophylaxis, failure to adjust for renal function, and not accounting for drug interactions that affect DOAC metabolism 4