Yikes , a good friend of mine has something similar. I think it's called degenerative bone disease. It is all over his body. He can literally pop every joint in his body in and out of socket. He has good days and bad days, but it, like you will never get better. I try to help him out as much as possible. That's a tough pill to swallow. I'm for you, and hope it stays mild for a long time. I believe you need a trike.