My rhuematologist (regular M.D.) recommends Cosamin ASU joint health supplement. It has glucosamine & chondroitin but also an avocado/soybean additive. It has actually been shown to help arthritis.

I have arthritis all over my body and it does help me. Regular glucosamine/chondroitin/MSM does nothing. I also take meloxicam daily, which is a prescription anti-inflammatory (NSAID)

As far as aging knees & other high use joints - most people over 50 have all kinds of small tears & arthritic changes. It has been shown that many of those people don't have any symptoms at all. In fact, some of the worst x-rays of joints often don't correlate with any joint pain (or minimal).