Knee Flashcards
Radiographs should be ordered after trauma to the knee if there is any of what 4 symptoms present?
- Joint effusion after direct blow or fall
- Inability to walk without limping
- Palpable tenderness over patella or fibular head
- Inability to flex knee to 90°
Should radiographs be ordered if a patient had twisting injury and is able to walk with no effusion present?
No
Isolated meniscal tears are present with what symptoms?
- Intermittent clicking and eventually chronic blocking or locking of knee joint motion
- Effusion
- Pain
What is the imaging of choice for evaluating menisci?
MRI
On an MRI menisci are seen as ___ signal intensity. Tears are seen as ____ signal intensity.
low (dark)
high (light)
In what direction are mensical tears most commonly oriented?
vertically
If there is a longitudinal extension of the vertical meniscus tear what is it called?
a bucket handle tear
Meniscus tears typically occur in a horizontal orientation due to what?
degenerative changes in older adults
What is the clinical presentation of a collateral ligament tear?
Pain, joint effusion, and instability
The LCL is injured from a ____ force
varus
The MCL is injured from a ____ force
valgus
What is the unhappy triangle?
Tears of the MCL, ACL, and medial meniscus
What is the imaging of choice for collateral ligament tears?
coronal T2-weight MRI
In a T2-weighted MRI the collateral ligaments appear ____.
dark
low signal intensity
Sports related ACL injuries occur at a rate of about how many per year in the US?
200,000
Women tend to experience ACL injuries up to __ times more often than men participating in same the sport
8
What is the MOI for a PCL tear?
external forces that strike the anterior aspect of the knee (such as in dashboard injuries)
What is the MOI for an ACL tear?
non-contact forces that place great valgus and rotary stresses on knee.
Such as when an athlete suddenly decelerates, turns, and hears the classic “pop” of rupture
Dynamic LE valgus is a combination of what 3 motions at the hip, knee, and ankle?
Hip: adduction and internal rotation
Knee: tibial abduction, tibial external rotation and anterior translation
Ankle eversion
How can radiographs evaluate cruciate ligament tears?
When there is associated avulsion fractures
What is the imaging of choice for cruciate ligament tears?
Sagittal T1-weighted MRI
What are the 2 clinical decisions rules for the knee?
Ottawa and Pittsburg
