short answer : depends .
I know a guy who fell off a roof and really wrecked his legs and feet - won a medal in the sydney paralympics on the track ( silver ) - and his legs were a really mess nowadays his biggest problem is having to have his shoes specially made .
I had polio as a child and my foots a disaster almost solid at the ankle , leg not much better but most of the time it´s not stopped me cycling and when fit I´m not the slowest guy I know .
rehab : do enough but don´t overdo it , a little everyday and listen to your body´s warnings , yes it hurts but if it starts to SUDDENLY hurt then stop and try again the next day .
having just recoverd from a dislocated hip and then accute tendonitis of the troublesome ankle you have my sympathy - crutches are a bore .
and remember " MAKE HASTE SLOWLY " good luck