First, I would suggest speaking to your PCP/other medical professional who is knowledgeable to your condition. They would be able to possibly give you some more specific info based on your current condition.
That said, I think a reasonable .22 would be fine. I would definitely reccomend a heavier rifle, to absorb more of the recoil. After talking to your MD, I would see if someone has one you can try before buying one, just to make sure your body can handle it.