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: Surgery
Most common cause of AVN of the hip is 
Select and explain. 
A. Idiopathic, B. Alcoholism, C. Caissons Disease, D. Fracture neck of femur
A: Idiopathic
Answer: A: Idiopathic 
Explanation: Answer- A. IdiopathicCauses ofAVN hipldiopathic (most common)Infection- septic ahritis, osteomyelitisHematological malignancies- leukemia, lymphomaAlcohol,coicosteroidsSLEPregnancyCassions diseaseHyperlipidemiaPehes diseasIonising radiation