Small fractures of the forearm heal in about four weeks when immobilized in a cast. More severe forearm fractures may need to be repaired surgically, and then immobilized for up to 12 weeks.
Small fractures of the humerus may heal in as a few as eight weeks in young, healthy patients. However, more serious humerus fractures may take more than 12 weeks to mend. This is especially true in elderly people.
Up to six months of rehabilitation exercises can be necessary for muscle and strength to recover after forearm and humerus fractures.