Lachman maneuver primarily assesses the integrity of which ligament?

Lachman maneuver primarily assesses the integrity of which ligament?

• A. Medial collateral ligament
• B. Anterior cruciate ligament instability
• C. Posterior cruciate ligament
• D. Lateral collateral ligament

Answer: (B)

The main idea is that the Lachman maneuver tests the ACL, the key restraint against forward movement of the tibia relative to the femur when the knee is flexed modestly. Positioning the knee about 20–30 degrees of flexion places the ACL as the primary stabilizer for anterior tibial translation, while the hamstrings are less able to influence the test and the collateral ligaments aren’t the main stabilizers being evaluated. A positive finding—excessive anterior translation with a soft or absent end feel—suggests ACL rupture. The anterior drawer test can also assess the ACL but is less sensitive acutely and more affected by hamstring tone and effusion, making Lachman the preferred test for ACL integrity.

The main idea is that the Lachman maneuver tests the ACL, the key restraint against forward movement of the tibia relative to the femur when the knee is flexed modestly. Positioning the knee about 20–30 degrees of flexion places the ACL as the primary stabilizer for anterior tibial translation, while the hamstrings are less able to influence the test and the collateral ligaments aren’t the main stabilizers being evaluated. A positive finding—excessive anterior translation with a soft or absent end feel—suggests ACL rupture. The anterior drawer test can also assess the ACL but is less sensitive acutely and more affected by hamstring tone and effusion, making Lachman the preferred test for ACL integrity.