ANTERIOR LACHMAN'S TEST

TEST POSITIONING

The client lies supine with the test knee flexed to 20 to 30 degrees.

The therapist stands with the proximal hand on the client's distal thigh (laterally) immediately proximal to the patella, and the distal hand on the client's proximal tibia (medially) immediately distal to the tibial tubercle.

ALTERNATE TEST POSITIONING

The therapist places his or her flexed knee under the client's test knee, with the proximal hand over the distal thigh (anteriorly) and distal hand on the client's proximal tibia (medially), just distal to the tibial tubercle.

ACTION

From a 'neutral' (anterior-posterior) position, apply an anterior force to the tibia with the distal hand while stabilizing the femur with the proximal hand.

The same procedure applies to the alternate test positioning.

POSITIVE FINDING

Excessive anterior translation of the tibia as compared to the uninvolved knee with a diminished or absent endpoint is indicative of a partial or complete tear of the anterior cruciate ligament (ACL).

CONSIDERATIONS & COMMENTS

Increased anterior tibial translation is not in and of itself indicative of ACL pathology.

For example, a torn PCL will allow the proximal tibia to translate posteriorly, thus producing increased anterior translation during the anterior Lachman's test.

Meniscal tear (primarily of the posterior horn) may also contribute to an anterior translation.

Therefore, the presence and quality of the endpoint must be determined before ACL integrity may be accurately assessed.

Though individuals may choose to always use the dominant hand for the translation assessment, it is recommended to stabilize the tibia on the medial side to prevent the possibility of increased external rotation of the tibia that can contribute to increased anterior translation.