I sprained my ankle about a week ago, and at first was given an ACE wrap and stirrup aircast, but that wasn't doing the trick, so I got a script for a walking boot.
The doctor didn't specify tall or short, so the medical supply place gave me a short one. It's not that short -- mid shin, probably about 3 inches shorter than a "tall" one, but I'm wondering if I should have a tall one. I just ordered one off Amazon so that I can see the difference between the two and then of course, if I need the tall one I'll have it.
Doesn't hurt to try both sizes, but I would think the shorter might be more comfy for you. Hope you feel better soon. Sprained ankles are a pain for sure!
The taller one makes the ankle more immobile, less lower leg muscles working. The shorter one is easier to walk in, easier to put on, less immobilization. Because you don't have a fracture, I agree with Ron go with the short one.