I stopped playing guitar for about five years, and when I came back to it my fingers wouldn't work - osteoarthritis. So I took up the autoharp. With the left hand, one finger=one chord. And not a lot of pressure required, and it comes from the arm not the finger joints. The right hand fingers just need the ability to move fast - no pressure at all. If you want to stick with the guitar, look at Keith Richards hands sometime! It must still be possible. If you have osteoarthritis, once the nodule have fully developed, the pain tends to go.