Review Question - QID 4897

A 5-year-old boy with cerebral palsy returns to your office for routine follow-up. He meets Gross Motor Function Classification System level V criteria. Since his last visit, his mother complains it is getting more difficult to get him well seated and change his diapers. She notes pain during sitting and during any movements of either hip. Physical examination reveals limited abduction with tight adductors along with pain with any hip of range of motion. His mother notes that he has already had several months of therapy and has not improved. His radiograph is shown in Figure A. What is the most appropriate treatment?