Why does torn MCL cause passive abduction?

[drmedstudent]

FA 2010 pg 366 says "Abnormal passive abduction indicates a torn MCL." Im not sure I understand what they're saying. Are they referring to valgus/varus stress concept?

If anything, MCL tears occur in valgus stress and that would indicate ADDuction.....

can any1 fill me in on this?

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[illixir]

They are saying that once the MCL is torn, abduction will be abnormally present at the knee joint because the MCL is what restricts that movement. If you think about where the MCL is positioned on the body it should make sense, abduction is when the lower leg will be moving laterally away from the body.

 

[username456789]

FA 2010 pg 366 says "Abnormal passive abduction indicates a torn MCL." Im not sure I understand what they're saying. Are they referring to valgus/varus stress concept?

If anything, MCL tears occur in valgus stress and that would indicate ADDuction.....

can any1 fill me in on this?

If you are able to abduct the leg (using the knee as a pivot point or whatever), it's clear that whatever was "holding together" the femur and the tibia medially is busted.

(He had a fibulectomy).

 

[drmedstudent]

oh ok hahaha...i get it. is this what occurs upon valgus stress

 

[turkeyjerky]

fantastic drawing!

just curious, do you guys actually call that "abduction". i've only heard it as valgus testing

 

[kryptik]

i doubt they will put "valgus testing" in the stem, they will normally describe it is abducting