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': 'Which one of the following tests will you adopt while examining a knee joint where you suspect an old tear of anterior cruciate ligament - \nSelect and explain. \nA. Posterior drawer test, B. Mc Murray test, C. Lachman test, D. Pivot shift test', 'role': 'user'}, {'content': "Answer: C \nExplanation: Lachman's test is the most sensitive test for anterior cruciate ligament tears.\nIt is done with the knee flexed at 20 degrees. So it can be done in acute as well as chronic injuries. (because in acute cases with hemarthrosis more flexion is usually not possible so performing anterior drawer test is difficult).", 'role': 'assistant'}]