Review Question - QID 9006

A 13-year-old male has had a several year history of right ankle pain and frequent sprains. Over the past year it became progressively worse until he could not participate fully in athletics and other activities due to pain. He recently wore a weight-bearing cast for 4 weeks and rested from all activities followed by formal physical therapy and use of a custom orthosis. His ankle felt initially better, but within a week of returning to his activities the pain returned. On physical exam he has a rigid flat foot, and no instability about the ankle. Figure A is a lateral radiograph of his ankle. What is the next best step in management?