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Diagnostic Imaging > Knee > Flashcards

Flashcards in Knee Deck (33):
1

What 4 things should be assessed when viewing the knee from an AP projection?

- Patellar Apex at level of joint line
- Joint space heights
- Tibiofemoral alignment
- Parallel to tibial plateau

2

Why is the medial femoral condyle magnified in a lateral view of the knee?

- Farther from plate

3

How long should the patellar tendon be when viewing the knee from a lateral projection?

- Equal to the length of the patella + or - 20 %

4

How should the intracondylar notch of the femur be shaped?

- Like a U

5

What may be found within the joint as seen through the PA tunnel view of the knee?

- Loose bodies
- Joint space narrowing

6

What is the sunrise view of the knee?

Tangential view of patella

7

What can be assessed using the joint space of the patella femoral joint?

- Cartilage thickness

8

What are 3 measures of the sulcus and congruence of the patellafemoral joint?

- Sulcus angle
- Congruence Angle
- Patellar Tilt

9

What is the sulcus angle? What is normal?

- Lines formed between deepest point of groove and highest point of each femoral condyle
- Normally 138 degrees + or - 6

10

What is the congruence angle? What is normal? What is a lateral sublux?

- Line bisects sulcus angle
- Line between apex of sulcus angle and most posterior point on the patella
- Normally - 6 degrees
- Lateral sublux: + 16 degrees

11

What is patellar tilt?

- Line connecting medial and lateral edges of patella
- Line a horizontal
- Normal: < 5 degrees

12

What is the specificity, sensitivity, and accuracy of the patellar tilt measurement?

Spec: 92 %
Sens: 85 %
Accuracy: 89 %

13

In a fracture of the tibial plateau, although the actual fracture may be difficult to see, what is indicative of a fracture?

- Abnormal fat and blood within capsule

14

How will a bucket handle tear appear on imaging?

- Space in meniscus with surrounding tissue intact

15

How will a horizontal/ vertical meniscal tear appear on imaging?

- Horizontal/ vertical line through dark meniscal space

16

On what imaging is an ACL best visualized?

- T1 MRI

17

What makes the a full visualization of the ACL difficult in a normal lateral view?

- Medial course of ligament

18

How should the ACL be shaped?

- Ruler straight with a very slight convex shape inferiorly

19

What is a Segond fracture? What is it associated with?

- Fracture of lateral tibial plateau
- Internal derrangement of knee, most commonly the ACL

20

What is the Blumensaat angle? What is normal/ abnormal? What is a normal angle?

- Line running parallel to posterior surface of femur
- Line running course of ACL
- If the apex points superiorly, it is normal
- If apex points inferiorly, it is abnormal
- Normally - 13 degrees

21

What is the anterior tibial line? What is normal?

- View knee sagitally
- Vertical line from posterior margin of tibia
- Should not cut through posterior horn of lateral meniscus

22

How will an acute torn ACL appear on MRI?

- Hemmorrhage in intracondylar notch area
- Bone bruises often seen in T2

23

What 3 secondary effects are usually needed to identify a chronic partial ACL tear?

- Segond fracture
- Bone bruise
- Hemorrhage

24

How are Blumensaat line angles shaped in a partial ACL tear?

- Can be normal

25

Since partial ACLs are difficult to visualize, what is the result?

False negative reports

26

How is a normal PCL shaped?

- Deep black structure from posterior tibia to the middle of the femur

27

How can a torn PCL present on images?

- Disrupted or enlarged in T1

28

How is a torn MCL visualized?

- Edema and joint effusion

29

What other structures is the LCL associated with?

- Arcuate ligament
- Fabellofibular ligament
- Popliteus tendon
- Biceps femoris tendon
- Conjoined tendon

30

What should the patella be aligned with in an AP projection of the knee?

- With the joint line

31

What is the Pittsburgh knee rule?

- History of blunt trauma
AND
< 12 yo
>50 yo
OR
Can't walk 4 WB steps

32

Is the pittsburgh knee test sensitive or specific?

Sensitive

33

What is the Ottawa knee rule?

- History of trauma
AND
any of the following:
- Tenderness at fibular head
- Isolated tenderness of the patella
- Inability to flex knee 90 degrees
- Inability to walk 4 steps immediately AND in clinic