This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Orthopaedics
[{'content': 'Post polio, a child has gastronemius power - Grade 2, peroneus longus- Grade 3, tibialis anterior - Grade 4. Deformity present is: \nSelect and explain. \nA. Calcaneo valgus, B. Calcaneo varus, C. Equino valgus, D. Equino varus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans: a (Calcaneo valgus)Ref: Textbook of Orthopaedics - Ebenezar, 4th ed.Tibialis anterior and peroneus longus which are the primedorsiflexor and evertor position the foot in calcaneo valgusdue to unequal muscle pull in the above case.Calcaneo valgus - Dorsiflexion at ankle and (eversion) at subtalar joint.Calcaneo varus - Dorsiflexion at ankle and varus (inversion) at sub talar joint.Equino valgus - Plantar flexion at ankle and valgus at subtalar jointEquino varus - Plantar flexion at ankle and varus at subtalar joint.', 'role': 'assistant'}]