Which maneuver is most appropriate to assess ACL integrity and is considered highly sensitive?

• A. Posterior drawer test
• B. Anterior drawer test
• C. Lachman test
• D. Pivot shift test

Answer: (C)

The Lachman maneuver is the most sensitive way to assess ACL integrity. It targets anterior translation of the tibia relative to the femur when the knee is in a mid-range bend, about 20–30 degrees. At this angle, the ACL is under tension and the tibial movement reflects its intactness or rupture more clearly, while guarding or muscle tone doesn’t mask the laxity as much as in other positions.

To perform it, stabilize the femur with one hand and grasp the proximal tibia with the other, then gently pull the tibia forward. Compare with the opposite knee. A positive finding shows increased anterior translation and a soft or absent end feel, which suggests ACL rupture.

The other tests are less ideal for isolating ACL injury: the posterior drawer mainly tests the PCL, the anterior drawer at 90 degrees is more prone to false negatives from hamstring guarding, and the pivot shift evaluates rotational laxity but is more technically demanding and not as universally sensitive for isolated ACL tears.