Which test is best for assessing ACL integrity in suspected injury?

Which test is best for assessing ACL integrity in suspected injury?

• A. Pivot shift test
• B. Patellar grind test
• C. Lachman test
• D. Thessaly test

Answer: (C)

When a suspected ACL injury is in question, the test that best reveals ACL laxity is the Lachman test. It is performed with the knee flexed about 20-30 degrees, which places the ACL as the primary restraint to forward movement of the tibia. This angle minimizes hamstring guarding and makes anterior tibial translation a direct reflection of ACL integrity. A positive finding is increased forward movement of the tibia with a soft or absent end-feel compared to the opposite knee, indicating an ACL rupture. This makes it more sensitive than other laxity tests, especially in the acute stage when swelling and guarding can mask issues. The pivot shift test also assesses ACL injury but is more technique‑dependent and less reliable in many settings, while the other tests are aimed at different structures (patellofemoral joint or meniscus) and don’t specifically evaluate ACL integrity.

When a suspected ACL injury is in question, the test that best reveals ACL laxity is the Lachman test. It is performed with the knee flexed about 20-30 degrees, which places the ACL as the primary restraint to forward movement of the tibia. This angle minimizes hamstring guarding and makes anterior tibial translation a direct reflection of ACL integrity. A positive finding is increased forward movement of the tibia with a soft or absent end-feel compared to the opposite knee, indicating an ACL rupture. This makes it more sensitive than other laxity tests, especially in the acute stage when swelling and guarding can mask issues. The pivot shift test also assesses ACL injury but is more technique‑dependent and less reliable in many settings, while the other tests are aimed at different structures (patellofemoral joint or meniscus) and don’t specifically evaluate ACL integrity.