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': 'All of the following are the causes of sudden increase in pain in osteochondroma, except - \nSelect and explain. \nA. Sarcomatous change, B. Fracture, C. Bursitis, D. Degenerative changes', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Osteochondroma usually presents as a painless swelling.\nThe occurrence of pain suggests some complications such as :\nBursitis at the tip of the swelling.\nFracture through the stalk of the osteochondroma\nImpingement on or tethering of neighbouring structures such as a tendon, muscle or nerve.\nMalignant transformation', 'role': 'assistant'}]