This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Orthopaedics
[{'content': 'A 45-year-old was given steroids after renal transplant. After 2 years he had difficulty in walking and pain in both hips. Which one of the following is most likely cause - \nSelect and explain. \nA. Primary osteoarthritis, B. Avascular necrosis, C. Tuberculosis, D. Aluminum toxicity', 'role': 'user'}, {'content': 'Answer: B \nExplanation: This patient has : -\n\nHistory of steroids intake\nPain in both hip\nDifficulty in walking\n\n\nThe diagnosis is AVN of the hip.\nIn 50% of idiopathic cases and 80% of steroid-induced AVN are bilateral.\n\nAbout other options\n\nTuberculosis of hip is usually unilateral.\nPrimary osteoarthritis of hip does not occur at 45 years and has nothing to do with steroid intake.\nAluminium toxicity does not cause bilateral hip pain.', 'role': 'assistant'}]