[Drdogface]

That's not much displacement at all and it should heal fine. When splinting or casting you must immobilize the joint above and below the fracture.... If there is a hard bottom surface to the air cast to walk on and the weight bearing goes from the bottom of the cast up to the leg at the top w/o bearing on the foot it will be fine...The purpose, of course, is to not allow motion at the fracture site...

Personally I would have used a fiberglass cast, split in half after setting, then taped the halves together...that allows it to be changed as needed...

Just my 2 cents...