Walking. Use it or lose it. I have arthritis in both my knees, and have been given various pain medications to help, including opiates. But honestly, the thing that helps the most is plain walking. Having a dog helps. I only take occasional pills now, and that's aspirin.
Saying that, it's not like it cures the arthritis. Some times I sit here in pain, sometimes acute, sometimes not. It's just part of getting older.
I recall when my knees were especially bad, it was winter, and I was out walking my dog. Suddenly the ground turned to ice and I went down, extending my knees like a gymnast doing the splits. The pain was horrendous. I paused for long while, wondering if I would be able to get myself back up, especially with a confused dog still held on a leash. However, I did manage to get up, and guess what? NO pain in my knees! They felt better after the fall than before it.
Ain't life weird.