After total knee arthroplasty, which prophylaxis is commonly used to reduce the risk of DVT?

• A. LMWH
• B. Warfarin
• C. Aspirin
• D. None

Answer: (A)

After total knee arthroplasty, the risk of blood clots is high because of immobility, surgical vessel injury, and a postoperative hypercoagulable state. To lower this risk, pharmacologic prophylaxis is routinely used alongside mechanical methods. Low-molecular-weight heparin is commonly chosen because its anticoagulant effects are predictable when given subcutaneously, it usually doesn’t require regular blood monitoring, and it has strong evidence from orthopedic surgery trials showing a meaningful reduction in deep vein thrombosis and pulmonary embolism after knee replacement.

Warfarin, while effective, requires careful monitoring of the INR and has more interactions and variability in onset, making perioperative management more complex. Aspirin is used in some protocols, but it generally provides less robust protection against DVT compared with LMWH, and its effectiveness can be variable depending on the patient and protocol. Doing nothing would leave the risk untreated. So the most commonly used prophylaxis in this context is low-molecular-weight heparin.