Anonymous wrote:believe it or not, you can twist your knee while sleeping. It's probably fluid build up from the trauma. I take NSAI when this happens to me.

Oh geez! Leave it to me to hurt myself sleeping!

yep torn meniscus

Meniscus!

This was one sign I had of a torn meniscuc

believe it or not, you can twist your knee while sleeping. It's probably fluid build up from the trauma. I take NSAI when this happens to me.

Bursitis.

OP here - no other symptoms. I've had knee problems before, but there was sharp/acute pain. The only pain here has been in the back of my knee. The rest is just the pressure from the swelling. Thanks!

It could be so many things, and the pain could actually be a consequence of the swelling.

But one possibility is gout.

Swelling of the knee can be a sign of Lyme disease. Do you have any other symptoms?

My knee will every once in a while swell up (on the right side of my left knee). The only real pain is behind my knee. What could it be?