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': 'Prosthesis at the head of the femur applied in - \nSelect and explain. \nA. 40 years young male with # head of femur, B. 40 years young male with # neck of femur, C. 40 years young male with posterior dislocation of hip, D. 65 years old male with nonunited fracture neck of femur', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Non-united fracture means long-standing fracture which has not united. In terms of neck fract,ure non-union is considered when the fracture is not united even after 6 months.\nFor long-standing fracture in 65 years old male, the treatment of choice is prosthetic replacement either semi-replacement or total replacement depending upon the presence or absence of pre-existing arthritis.', 'role': 'assistant'}]