When assessing for an anterior cruciate ligament (ACL) injury, which test would typically be performed?

The Lachman's test is a primary clinical assessment used to determine the integrity of the anterior cruciate ligament (ACL). This test specifically evaluates the amount of anterior translation of the tibia relative to the femur, which is an indicator of ACL stability.

When performing the Lachman's test, the patient lies supine while the examiner stabilizes the femur with one hand and pulls the tibia forward with the other hand. A positive test result, indicated by excessive forward movement of the tibia, suggests a tear or significant injury to the ACL. This is particularly relevant because the ACL is critical for maintaining knee stability, especially during activities that involve pivoting or sudden stops.

Other assessment tests mentioned, such as the varus and valgus stress tests, primarily evaluate the integrity of the collateral ligaments, while the posterior drawer test assesses the posterior cruciate ligament (PCL) rather than the ACL. Thus, the Lachman's test is recognized as the most direct and reliable test for assessing ACL injuries, making it the appropriate choice for this scenario.