- See:
-
Anteromedial Instability
-
Anterolateral Instability
-
external rotation
- Discussion:
- internal-rotation laxity increases w/ knee flexion, w/ largest amount
(25 degrees) seen in the 20 to 40-degree range of knee flexion;
- of all of structures around the knee, only
MCL and
ACL play an
important role in the restraint of
Internal Rotation;
- isolated cutting of either of these ligaments results in a marked increase
in internal-rotation laxity, w/
MCL playing a larger role;
- combined sectioning of
ACL & MCL results in much more laxity than
does sectioning of either ligament alone;
- loss of
Anterior Cruciate Ligament in combination w/ loss of
LCL
or posterolateral structures, or both, also results in increased
rotatory laxity of approximately 35 degrees;
- cutting of
PCL results in no increase in internal-rotation laxity;
- coupled anterior and medial translation occurs with internal rotation;
- loss of
ACL results in increase in coupled anterior translation;
- isolated loss of
PCL,
LCL, or posterolateral structures does not
affect the coupled motion;
- internal-rotation laxity is also increased following medial or lateral
meniscectomy;
