My doctor says I’m at high risk for blood clots so I have to take a blood thinner when I have my total knee replacement. What makes me so risky? How long will I have to take this drug?

Blood clots called deep venous thrombosis (DVT) can be a serious complication. It’s important to try and reduce or eliminate as many risk factors as possible. You may want to ask your surgeon to review your personal risk factors with you.

Risk factors you can do something about are called modifiable risk factors. Things you can’t change about yourself are nonmodifiablerisks. For example, age over 75 is a nonmodifiable risk factor.

Most of the risk factors for DVT are nonmodifiable. Other nonmodifiable risk factors include previous history of blood clots, cancer, or immobility. History of blood clots includes you or anyone in your immediate family.

Having hip or knee surgery increases your risk dramatically. Less powerful risk factors include being overweight, having varicose veins, and pregnancy.

Your doctor can conduct a screening test for DVT risk factors. A simple test of adding risks up can help predict your risk. Each risk is given a point value. After adding up your points, your risk can be judged as low, moderate, or high.