After having a dvt where clot is behind knee, is it better to wear compression stockings below knee or above?

Depends: Once a diagnosis has been made, and anticoagulants(blood thinners) have been started and the patient's condition is stable , the md may recommend ambulation (walking) and compression stockings to prevent other clots. The stockings are graduated in pressure starting at the ankle. The md most familiar with you current condition should be consulted on thigh high or knee high hose.

Knee high: Studies have shown that regardless of where your clot was, knee high stockings are all you need. What is more important is that your stockings give you 30-40 mm hg of graduated compression. Ted hose are not enough. You also need to wear them every day for at least two years in order to reduce your risk of getting a complication of dvts you don't want to have called post thrombotic syndrome.

Below the knee.: The purpose of compression stockings is to both reduce swelling and increase the venous return. These two functions aid in decreasing venous hypertension and stasis which can lead to chronic venous insufficiency. Below the knee compression is all that is necessary for your problem. However, if your clot was above the knee then i would recommend above knee compression initially for several months.