Wierd knee pain

Sometimes in the middle of the night I wake up with an excrutiating pain in my knee. I inevitably try to bend it, but the pain’s just too unbearable. I eventually drift back to sleep, and when I wake in the morning, the pain is gone. I’m not even 20 yet, so I couldn’t say this is just me getting old. Anyone have any ideas as to what it’s caused by?

Bursitis or Sports-related are leading causes for a youngster’s knee pain, per WebMD.

Osgood-Schlatter disease is likewise common, and eventually goes away.

http://familydoctor.org/handouts/135.html

But I’ve always heard of that in relation to activity (i.e., the pain occurs during and after activity, not spontaneously in the middle of the night).

I had bursitis in my knee about 5 years ago, but I haven’t been doing much physical activity as of late.

OMG!!!
xgxlx, I had the exact same thing happen to me for the first time ever, early this morning!
I cried out in pain it hurt so much to bend it. And I kept trying, and kept crying out. I just kept it straight and went back to sleep. I had completely forgotten about it until I saw this thread.

I’ve never had any problems with my knees at all, but I have been doing a little more walking lately than normal, but nothing out of the usual.

I’ve had the same problem sporadically for years, only with my elbow.