Check into the work of Louis Kuhne, who used steam heat and detoxing friction sitzbaths to cure loads of folks of thing like this.
I am letting you know this because of all the good it did me..
Get a wet towel, wring it out until it won't drip and wrap the knee in it, then a plastic garbage bag over that, then a heating pad (I like the extra-long ones you can get at Walmart) over the garbage bag.
Wrap the heating pad *all the way around the knee*, both front and back.
Turn the heating pad on High (I use High myself) or Medium until the knee gets good and hot, then turn off the heating pad and let the knee cool itself down. Don't turn the heat back on until the knee has cooled off..
Do this with the heating pad 3 or 4 times during the night, and I'll bet you'll see a strongly positive difference by day 2 at the very latest.
If you can get Dr. Christopher's "Bone, Flesh and Cartilage" herbal formula, make a strong decoction of it and soak the towel with that and it will work better, but plain water works quite well, and is all Dr. Kuhn used in his day. They didn't have heating pads then.
It is crucial to use *moist heat* for this; Do not leave out the wet towel..