Debs, bones of the foot are not that dissimilar to those of the hand, and casts do not help that much, as I am finding with my scaphoid - again. The removable splints can be tailored to each injury and some movement is necessary so that other joints do not seize up.
When Michael got stood on playing football he bruised a bone in the top of his foot and the boot he was given had a lift in the heel to help him 'perambulate', took about four weeks.