A 68-year-old man from Delhi presents to the orthopaedic clinic with a 3-month history of progressive left hip pain, morning stiffness lasting 45 minutes, and difficulty walking. On examination, he has restricted internal rotation and abduction of the left hip, and a positive FABER test. Plain radiographs show joint space narrowing, osteophytes, and subchondral sclerosis of the left hip joint. What is the most appropriate next step in management?