- See:
-
Anterior Cruciate Ligament
-
Pivot shift
-
Clunk Test
-
Losee Test
- Discussion:
- to perform anterior drawer test, examiner grasps pt's tibia & pulls it
forward while noting degree of anterior tibial displacement;
-
anteromedial rotatory instability:
- positive anterior drawer test in neutral tibial rotation;
- anteromedial instability is apparent when w/ stress testing medial
plateau of tibia rotates anteriorly & externally as the joint opens
on the medial side;
- drawer test is accentuated in 30 deg of external rotation;
- drawer test is reduced w/ tibia in 15 deg of
internal rotation;
-
anterolateral rotatory instability
-
internal rotation:
- in one plane anterior instability, drawer test becomes negative as tibia
is internally rotated to 30 deg, due to tightening of
PCL;
- positive anterior drawer sign that is changed very little by internal
rotation of tibia suggests PCL is torn;
-
internal rotation tightens structures on posterolateral side of knee;
- normally there should be reduced movement when the leg is pulled
forward, even if the
ACL is torn;
-
external rotation:
- tightens posteromedial portion of joint capsule;
- normally there should be reduced forward movement of the tibia on
femur, even if ACL is torn;
- if forward movement w/ leg in
external rotation is equal to forward
movement w/ leg in neutral position, then there is injury to:
-
ACL;
- posteromedial portion of joint capsule;
- possibly
MCL;
- Lachman variation:
- performing examination w/ knee at 15-25 deg of flexion;
Ligamentous restraints to anterior-posterior drawer in the human knee. A biomechanical study.
Butler DL.
Noyes FR.
Grood ES.
Journal of Bone & Joint Surgery - American Volume. 62(2):259-70, 1980 Mar.
Long-term functional results. in patients with anterolateral rotatory
instability treated by iliotibial band transfer.
The role of incompetence of the anterior cruciate and lateral ligaments in
anterolateral and anteromedial instability. A biomechanical study of
cadaver knees.
