I broke my wrist once, and needed a full arm cast for 3 weeks to complelty immobile everything, kind of like how Tina needed a leg cast for an ankle. After 3 weeks I got the arm cast off, and had a cast only on the forearm. 

I had my cast from late September to early November, in Connecticut, and it was awful. I can't even imagine a full leg cast in a Southern California summer.