This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skeletal infections, Subject name: Orthopaedics
[{'content': "Painless effusion in joints in Congenital syphilis are called - \nSelect and explain. \nA. Clutton's joint, B. Charcot's joint, C. Baon's joint, D. Chronic, osteomyelitis", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Symmetrical ahrosis especially involving knee joint.Painless effusions in joints in congenital syphils are cluttons joints IMAGES SHOWING SYPHILITC BONY LESION AND DEFORMITY REF : MAHESWARI 9TH ED', 'role': 'assistant'}]