ADT and Door Stopper Effect

ADT (Anterior drawer test) is performed to detect Anterior cruciate ligament( ACL) injury.

The anterior cruciate ligament has two bundles named on the basis of tibial insertion:

1. Anteromedial: tight in flexion; primarily an anterior restraint; evaluated by Lachman and anterior drawer tests
2. Posterolateral: tight in extension; primarily a rotatory restrain; evaluated by pivot shift test

Both cruciate ligaments will receive their blood supply via branches of the middle geniculate artery and the fat pad.

Composition: 90 % type I collagen and 10 % type III collagen

Mechanism of Door stopper effect

With the knee flexed to 90 degrees for classical ADT, the medial meniscus is attached to the tibia, obstructs against the acutely convex surface of the medial femoral condyle, and has a “door stopper effect” hindering anterior translation of the tibia.

But with the knee extended, the flat weight-bearing surface of the femur doesn’t obstruct the forward motion of the meniscus and tibia when anterior stress is applied.

Anterior Drawer Test in Internal rotation of the tibia

ADT in Neutral rotation of the tibia

ADT in External rotation of the tibia

False-Negative Drawer test:

1. Door stopper effect of the posterior horn of the medial meniscus
2. Hemarthrosis and hamstring spasm

See also: Knee Examinations

See also: ACL Injury treatment options