I've broken Left hand when I was young. My pinky is sometimes a problem. I get still get weird spasm sometimes even after all those years. because of that, I play a lot more with the three other fingers. I do think Lisa is right about it being therapeutic. Sure, my pinky is limiting me sometimes but it is still 80-90% functional. I do beleive having played guitar has given me some sort of physical readaptation on a level regular exercises wouldn't have. Inner hand muscles are hard to train. Guitar playing is a great way to make them work. It requires movements you don't normally do in your everyday life.
You do have to be extra careful and listen to your body. Stop at the first sign of pain. Even if you're having the time of your life :) It's sometimes frustrating but it better in the long run.