More than 20 years ago, I fell off a roof and badly sprained my ankle. After nursing it for a couple of months, I was pretty much able to do everything I usually did and forgot about it. Now lately, that same ankle is getting stiff and sore. Is it possible they are related?

Yes. When a ligament is torn, as can happen with a moderate or severe sprain, the bone it's attached to can also be damaged. The injury can cause the bone to lose its ability to absorb shock, resulting in more wear and tear on the joint. This condition is called osteoarthritis, or degenerative joint disease. This could be the cause of your symptoms. Ask your health care provider to look at it and give you an opinion.