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: Orthopaedics
[{'content': 'Commonest dangerous complication of posterior dislocation of knee is - \nSelect and explain. \nA. Popliteal artery injury, B. Sciatic nerve injury, C. Ischaemia of lower leg compartment, D. Femoral artery injury', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Dislocation of the knee\n\nThis rare injury results from severe violence to the knee so that all of its supporting ligaments are torn.\nIt is a major damage to the joint, and is often associated with injury to the popliteal artery.\nTreatment is by reduction followed by immobilization in a cylinder cast.', 'role': 'assistant'}]