A 17-year-old male football player presents with a 3-week history of insidious right thigh pain and a limp. He denies any history of trauma. He is afebrile and WBC, ESR, and CRP are within normal limits. On examination he has pain with resisted adduction of his right hip only. The remainder of the examination is normal. Imaging obtained is shown in figures A, B, and C. What is the next best step in treatment?