A 42-year-old man with a 10-year history of ankylosing spondylitis presents with acute-onset severe pain in the left hip, restricted internal rotation, and a positive FABER test. Radiographs show marginal osteophytes and joint space narrowing. MRI reveals early cartilage loss with subchondral edema. He is currently on NSAIDs and sulfasalazine. Which of the following is the most appropriate next step in management?