Posterior Cruciate Ligament? Strange that you've been told that surgery isn't the best route. Have you been MRI'd? Do they know the extent of your damage? I've had a wrecked ACL (ANTERIOR Cruciate Ligament) for half my life (Yup - got it bmxing...) and it's been a royal pain in the ass. Been wearing a knee brace on and off for nearly 18 years (I'm wearing one in my avatar - right knee..). About 10 years ago I got keyhole surgery to tidy up the tear and clean out and debris from the knee joint and it worked like a dream. But eventually it deteriorated again. I've been back to see the specialists and now I either have to live with the pain and the instability or get reconstructive surgery. 2 titanium screws, a piece of my Hamstring and up to 6 months rehab....but it's gonna be worth it. Very high success rate now with this type of surgery.
My advice is get as many opinions as you can and don't ignore it. The knee is one of the most crippling joints when it goes wrong, so don't mess around with it. If I get more info, I'll post it.