Comprehensive Osteopathic Medical Licensing Examination (COMLEX USA) Practice

Which provocative test is most sensitive for detecting an ACL injury?

1. Pivot shift test

2. Lachman test

3. Anterior drawer test

4. McMurray test

The correct answer is: Lachman test

The Lachman test is highly regarded for its sensitivity in detecting anterior cruciate ligament (ACL) injuries. This test effectively assesses the integrity of the ACL by providing a clear evaluation of the ligament's stability. During the Lachman test, the knee is flexed at approximately 20 to 30 degrees while the examiner stabilizes the femur with one hand and applies an anterior force to the tibia with the other hand. A key advantage of the Lachman test is its ability to isolate the ACL, making it particularly sensitive to even slight injuries. The test's specificity for ACL tears and its ability to minimize the influence of other structures make it a preferred method in both clinical and athletic settings. This is especially important since ACL injuries can occur in various sports and activities that involve sudden stops or changes in direction. In contrast, other tests, such as the pivot shift and anterior drawer tests, while valuable, do not consistently achieve the same level of sensitivity as the Lachman test. The pivot shift test, for example, is significantly influenced by the patient's level of relaxation and can be more difficult to perform accurately in certain populations. The anterior drawer test also requires the knee to be flexed at 90 degrees, which may not provide the same isolation