We use be able to after, you know, in grammatical situations when you can't use can. We don't really use the word cripple these days. It's an insulting word. So the appropriate word is disabled, a disabled person. Next is cast or plaster cast. If you break your arm then they will put a cast on your arm and keep it in one position so that the bone can repair itself. You probably know this one, right? We can't afford it. Right?"