I have Osgood-Schlatter disease (protrusion of shin bone just below knee cap). This device is very comfortable on my skin, easy to put on, and holds snugly. However, when I run (play tennis), the top portion tends to slide down. But the bottom portion holds firmly in place, and that's what really matters.
When I'm not running, the upper portion holds very well, and gives the muscles and ligaments the extra needed support.