Rosh Emergency Medicine Practice Test 2026 - Free Emergency Medicine Practice Questions and Study Guide

The Lachman test is considered the gold standard for diagnosing an anterior cruciate ligament (ACL) tear due to its sensitivity and specificity. During this test, the patient is typically positioned with the knee slightly flexed at about 20 to 30 degrees. The examiner stabilizes the femur with one hand while the other hand pulls forward on the tibia, assessing the amount of anterior translation.

The reason the Lachman test is preferred over the anterior drawer test is that it is less dependent on the patient's muscle tone and provides a clearer assessment of ACL integrity, especially in patients with acute injuries when swelling and muscle guarding might affect the results.

The other tests listed, while useful, do not have the same level of reliability for detecting ACL tears. The anterior drawer test assesses anterior tibial translation, but it can be less reliable in cases of acute injuries due to joint effusion and pain. The McMurray test is designed to evaluate meniscal injuries rather than specifically assess the ACL, and the valgus stress test is utilized to assess medial collateral ligament (MCL) injury. Therefore, the Lachman test stands out as the most effective and widely accepted method for diagnosing ACL tears.