Knee Ligamentous Dysfunction - Lecture 3 Flashcards
What two positions is the ACL most likely to be injuired in
Hyperextension
Valgus force (planted on foot)
A football player high tackles someone at their thigh. Which ligament is most likely torn
This high tackle at the thigh creates hyper extension. The femur is pushed backwards and the tibia stays stable (meaning its moved anterior in reference tot he body)
This is an ACL injury
KNOW: after ACL injury the leg may feel like its giving out
At the time of ACL injury there will be a loud pop
Why might someone have quad weakness / atrophy after ACL tear
Because the swelling from the ACL will push up on the quadrceps tendon. The swelling puts that tendon on stretch - so the golig tendon organs won’t want to fire to allow the quad to move. Essentially the quad is imhibited because of the swelling near the tendon
What position would an ACL pt be resting in?
Slight flexion of the leg (this is the most open packed position at the knee to allow for swelling)
KNOW: someone w/ ACL tear might have
* Hemarthrosis (more rigid palpation)
* Edema or effusion
KNOW: W/ ACL tear there will be decreased flexion and extension
* However, when we hit that end of extension (which is decreased) it will feel more lax (because ACL checks extension [becomes taut during extension])
The ACL prevents anterior or posterior tibial translation?
Anterior
KNOW: MMT for hamstring and quad will be decreased w/ ACL tears (due to swelling most likely both will be inhibited)
What should be stronger - quads or hamstrings?
Hamstrings
Hamstrings should be 2-3 times stronger than the quads
What muscle being to strong could cause ACL rupture?
Quads
If the quads throw that knee into excessive hyperextension and the hamstrings can eccentrically slow it down it could hit that hyperextension and cause that ACL to become super taut then rupture
KNOW: Functional tests for an ACL tear are meant for the copers - for someone who has a gresh ACL tear they arent gonna be able to do any of them
KNOW: The ACL has joint line tenderness at the knee
How to tell if the ACL is torn on a radiograph?
If the lines are clean and crisp = untorn
Wavy lines = torn
What kind of imaging do we do for an ACL tear?
MRI
Whats most important to do after ACL repair?
Mobility - want to get that full extension for heel strike phase (super important) (probs do this first)
General EX strengthening
Dashboard injuries are due to
tear of PCL
What movement causes PCL tears
Hyperflexion
Which direction translation of the tibia causes PCL tears?
Posterior translation (makes it taut then reuptures)
pt is walking up stairs and falls. Tibia hits the stair. What ligament is ruptured? (on test)
PCL
Tibia is pushed posterior causing this ligament to become taut
Posterior sag sign of tibia indicates?
PCL tear
* PCL check posterior translation of the tibia. If its not intact the tibia will sag posteriorly (nothing to hold it in place)
What has more stability issues ACL tear or PCL? Why?
ACL
Because it comes w/ that terrible triad (ACL, medial meniscus, MCL)
What kind of tear is this?
PCL
Pt is standing and is hit AP on the tibia. What kind of ligament injury is it?
PCL
Tibia translates posteriorly on the femur
Forced hyperflexion causes what kind of injury?
PCL