The Lachman test assesses for tears of which structure?

The Lachman test assesses for tears of which structure?

• A. PCL tears
• B. Medial collateral ligament tear
• C. Meniscal injury
• D. ACL tears

Answer: (D)

The Lachman test is aimed at assessing the anterior cruciate ligament (ACL). With the knee flexed about 20–30 degrees, you stabilize the femur and gently pull the tibia forward. If the ACL is intact, there’s only a small amount of anterior translation and a firm end point. If the ACL is torn, you’ll see markedly increased anterior translation with a soft or absent end feel. This makes the Lachman test more sensitive than the classic 90-degree anterior drawer in acute ACL injuries because it’s less affected by hamstring guarding and swelling. Other knee structures don’t fit this test: a PCL tear would produce posterior laxity or sag; an MCL tear causes laxity with valgus stress; and meniscal injuries typically show joint line pain, clicking, or locking rather than focal anterior translation.

The Lachman test is aimed at assessing the anterior cruciate ligament (ACL). With the knee flexed about 20–30 degrees, you stabilize the femur and gently pull the tibia forward. If the ACL is intact, there’s only a small amount of anterior translation and a firm end point. If the ACL is torn, you’ll see markedly increased anterior translation with a soft or absent end feel. This makes the Lachman test more sensitive than the classic 90-degree anterior drawer in acute ACL injuries because it’s less affected by hamstring guarding and swelling.

Other knee structures don’t fit this test: a PCL tear would produce posterior laxity or sag; an MCL tear causes laxity with valgus stress; and meniscal injuries typically show joint line pain, clicking, or locking rather than focal anterior translation.