This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Infection of Bones & Joints, Subject name: Orthopaedics
[{'content': 'Most commonly affected joint in syphilis: \nSelect and explain. \nA. Ankle, B. Knee, C. Hip, D. Elbow', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. b (Knee joint). (Ref. Maheshwari, Orthopaedics, 2nd ed., 165)CONGENITAL SYPHILIS# Most commonly affected joint in syphilis knee joint.# Syphilis may affect joints in following stages.# Early: During infancy, osteochondritis in the juxta epiphyseal region results in breakdown of bone & cartilage.# Late: A manifestation of congenital syphilis, CLUTTONS JOINTS is a painless synovitis occurring at puberty most commonly affecting knee & elbow mostly bilateral. DiseaseThe most commonly affected joint1TBSpine2Cong SyphilisKnee3PyogenicHip4OsteoarthritisKnee5RAIP6Charcot'sAnkle7DiabetesIntertarsal8Recurrent DislocationShoulder9SyringomyeliaShoulder10GoutFirst metatarso-phalangeal11PseudogoutKnee", 'role': 'assistant'}]