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': 'Late complication of Acetabular fracture \nSelect and explain. \nA. Avascular necrosis of lilac crest, B. Avascular necrosis of head of femur, C. Fixed deformity of the hip joint, D. Secondary osteoarthritis of hip joint', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Avascular necrosis - osteonecrosis of the femoral head may occur even if the hip is not fully dislocated. \nThe condition is probably overdiagnosed because of an erroneous interpretation of x-ray appearance following impacted marginal fractures of the acetabulum.\nOther complications : *iliofemoral venous thrombosis *sciatic nerve injury *heterotopic bone formation *loss of joint movement & secondary osteoarthritis', 'role': 'assistant'}]