Suggest Treatment For An Injury On The Forearm

Hi, my daugther broke her forearm in two places. She had plates put in. After 6 months one bone has almost healed but not the other. She has been using an ultrasound bone growth stimulator for the past 2 months. She's desparate to heal the other bone. Is there anything else she can do or special vitamins she can take?

Thank you so much for your help.