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
A PCL pt is trying to kneel. Where would they complain of pain?
Posterior knee (thats where the PCL is)
This pt is trying to do a straight leg raise. What ligament is messed up and whats the name of the sign they’re presenting w/?
PCL is messed up
Posterior sag sign - this is due to gravity - in PROM we would not have this because we negate gravity
actually I think its extensor lag sign
Will PROM be full w/ a PCL pt?
Yes, that ligament makes it taut - if that ligaments not there it will achieve that full ROM when passively moved (does depend on pain and swelling)
What two special tests do we do for PCL injuries?
Posterior drawer
Posterior sag sign
Which direction of mobilization would have a more lax end feel if there is a PCL tear?
Anterior –> posterior force at the tibia would be more lax (because that ligament essentailly checks posterior movement of the tibia on the femur. When its not intact the tibia will be able to translate more freely posterioly on the femur)
Would shift backwards more w/ PCL tear
pt is walking down stairs and feels like its buckling. Whats the issue and explain why
PCL tear
as they’re walking down stairs the femur is moving anteriorly (to take that next step) which means the tibia is moving posterior. If theres no PCL that tibia will translate to far posterior and will feel unstable
KNOW: Stability EX:
* Balance (different surfaces / eyes closed vs open / vertibations etc.)
What does the MCL limit primarily
Knee to valgus and lateral rotation forces
At what point in ROM is the MCL best at limiting knee valgus / varus?
20-30 degrees flexion
What position is the MCL most taut in?
full extension
At what position is the MCL best at limiting knee varus and valgus? (test question)
20-30 degrees
Then were going to have to pick the special tests that test in this degree amount to be testing for MCL
NOTE: the LCL also limits varus and valgus and this position is also best for it as well
What is likely going to be ruptured here?
MCL - because it limits valgus
Hes in extension so were proably also going to get the ACL / medial meniscus as well
What is likely torn here
This is a valgus movement so defiently MCL
Since there is some knee flexion we probs don’t get ACL / medial meniscus (those are more effected by hyperextension)
Do MCL/LCL pts report instability?
No - because the knee is normally sagital plane movement and these ligaments protect frontal plane movement
Is there swelling w/ MCL/LCL ligament rupture?
Yes - these are extraarticular ligaments (not in the joint capsule)
Is there lots of swelling w/ ACL/PCL tears?
Yes- even though their intracapsular they have loads of swelling
KNOW: MCL/LCL become taut at the end of flexion / extension - so if its partilly torn this positions are what are painful (because its most taut here)
KNOW: best way to test MCL is pushing into valgus at 30 degrees of knee flexion
What would be a really good muscle to strengthen for MCL issues?
Abductors because they pull it out of that valgus moment
What ligament is the primary restraint of knee varus forces?
LCL - rare for this to have issues
KNOW: In an ACL deficient knee, the LCL is a secondary restraint to anterior and internal rotation forces (helps the ACL)
What muscles pull the tibia anterior
Quads
KNOW: In closed chain the co-contraction of hamstrings/quads provides more stability to knee and less strain on ACL/PCL
Whats the best way to train the co contraction of hamstrings and quads?
Standing w/ some knee flexion
If you had full knee extension the joint would be locked and the muscles wouldnt have to work as hard
What 3 muscles limit anterior translation of the tibia? (pull it posterior)
1) Hamstrings
2) TFL
3) Soleus in wt bearing
What muscle limits posterior translation of the the tibia?
Quads
What muscles limit valgus stress at the knees (essentailly pull into varus) (3)
Pes anserine (sartourius, gracilis, semitendinosus)
Semimembraneous
Medial hd of gastronemius
What 2 muscles limit varus stress
Bicep femoris
Lateral hd of gastroc
Eyes open –> Eyes closed –> Conflicted vision (lots of stuff hapenning infront of you)
* The more narrow the BOS gets the harder it gets
* Also the ground makes its it easier / harder (stable surface? moving surface?)
This is how you rank an EX from easist to hardest
KNOW: most post surgical index shoot for affected side to be 85-95% as strong as unaffected
What is an autograft?
patients own tissue used
What is an allograft?
Donor tissue used
what part about this is rejection - this is normally not immediate happens several weeks - months lateral (not just a couple days later)
* Could even be a pig tendon
Need to be cautous of new worsening of symptoms weeks lateral because of rejection (or warm / streekieness)
What is a synthetic graft?
using some synthetic materal? (think plastic / metal)
* They typically combine this w/ allograft to weave it together to make the tendin the right side and shape
What is the most common place to get tissue for a pt?
Middle third of patellar tendon
can you strenghten a ligament?
No (not a contractile tissue) - but you can strengthen everything around it
if a pt is coping w/ ACL tear (no surgery) and reports that their knee has given out multiple times should we do surgery?
Yes, if it has given out more than 1 time surgery is indicated
What 4 things should potential copers for ACL rupture have?
1) Less than 1 episode of giving away
2) Over 80% 6 meter timed hop test (affected should be 80% as good)
3) Over 80% Knee outcome scale ADL subscale
4) Over 60% global rating of knee function
People who fall within this might benefit from not having surgery
Why might the structures around the ACL be damaged after years of being a coper?
If the ACL is damaged we will have reduced knee stability. This means other structures around will have to pick up the slack (meniscus / articular cartilage). Having surgery instead of being a coper can help us avoind these dengerative changes
Athletes should always have surgery - especially those requring higher level of pivoting
