Q. A 16-year-old boy is brought to the physician’s office by his mother for pain in the left hip for the past 2 months. He says that the pain initially was mild but gradually it is becoming worse and making him limp during activities. The pain is particularly worse at the night and it relieves by taking NSAIDs. But he is concerned about taking painkillers often. His temperature is 98.4°F (36.9°C), pulse is 88 beats per minute, BP is 120/76 mm of Hg and respiratory rate is 14/min. Physical examination shows point tenderness over the left hip joint with a mild decrease in the range of motion. Pain is reproduced with internal rotation of the hip in 90° of flexion and slight adduction. The neuromuscular examination is normal. A plain radiograph of the left hip shows a small nidus of lucency with surrounding sclerosis at the proximal end of the femur. What is the most likely diagnosis for this patient based on his clinical features and findings?