Nat Collins is fabulous! I limped in with bad arthritis in one knee and some arthritis in the other. I was just hoping to forestall a knee replacement by a few months. Now I walk almost normally. I can hold off on buying a new car because I can get in and out of my current one reasonably well, and I don't burst into tears due to the pain anymore. I have gotten fabulous personalized attention with a focus on problem-solving. I think that knee replacement might have to wait a few years! I could not recommend these folks more highly!