- See:
- Anterior Cruciate Ligament
- Anterolateral Rotatory Instability
- Clunk Test
- Losee Test
- Pivot shift
- Discussion:
- this is a variant of the anterior drawer test, in which the examination is carried out w/ the knee in 15 deg of flexion, and external rotation (relaxes IT band);
- for a right knee, the examiner's right hand grips the inner aspect of the calf and the left hand grasps outer aspect of the distal thigh;
- attempt to quantify the displacement in mm (comparing this displacement to the normal side);
- end point should be graded as hard or soft;
- end point is said to be hard when the ACL abruptly halts the forward motion of the tibia on the femur;
- end point is soft when there is no ACL & restraints are more elastic secondary stabilizers;
- Definition of Severity:
- clinical exam:
- mild: 0 to 5 mm laxity (greater than the uninvolved side)
- moderate: 6 to 10 mm laxity (greater than the uninvolved side)
- severe: 11 to 15 mm laxity (greater than the uninvolved side)
- when exam reveals such a large amount of translation always consider concomitant MCL tear / meniscal tear;
- KT-1000:
- greater than 11 mm of anterior translation of the injured side or greater than 3 mm of side to side difference (delta lachman) indicates ACL tear;
- following ACL reconstruction, laxity should be less than 3 mm compared to opposite side
Lachman test evaluated. Quantification of a clinical observation.
Injury to the anterior cruciate ligament producing the pivot-shift sign.
Arthrometric evaluation of knees that have torn anterior cruciate ligament.
What Really Happens During the Lachman Test? A Dynamic MRI Analysis of Tibiofemoral Motion.
Relationship Between the Pivot Shift and Lachman Tests: A Cadaver Study