I slipped on a slippery floor a few months ago, and caught myself landing on one knee. It didn t hurt much, and there was no outside bruising or swelling. Ever since then, my kneecap has been tender. If I kneel or hit it just the littlest bit, it really hurts! Although I have no problem bending, running, or any other kind of activity. There is no sign of anything on the outside. It hasn t improved at all since this first happened months ago!