This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thigh, Knee,Leg,Foot & Ankle injuries, Subject name: Orthopaedics
[{'content': 'A college football player repos knee pain along the medial joint line with intermittent locking and inability to fully extend the knee after a twisting injury to his right knee. He has a negative Lachman test and a positive McMurray test. What is the most likely diagnosis \nSelect and explain. \nA. ACL injury, B. PCL injury, C. Bucket-handle medial meniscus tear, D. Longitudinal veical lateral meniscus tear', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The patient has a bucket-handle medial meniscus tear after an acute injury. Such tears are associated with knee locking and a block to full extension. These tears are more common in young patients, often associated with ACL tears, and are the most commonly missed meniscal tear on MRI.', 'role': 'assistant'}]