Anyone experience back or hip problems because of their knees?

I have subluxing knee caps...first became noticable (first started hurting that is) about 5 years ago.

Recently I've been having some back pain. My doc and I talked about some possible causes, and I said that a hurniated disc didn't make sense because I'm young, and I haven't had any major accidents, but he said we shouldn't rule it out because my knees could cause troubles to my hips and spine.

Anybody actually have their hips or back hurt as a result of their knee trouble? How? What did you do about it?

Thanks for your input.