Most commonly affected joint in syphilis:

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