04 Knee Special Tests: Rotary Instability Flashcards Preview

7232 Ortho > 04 Knee Special Tests: Rotary Instability > Flashcards

Flashcards in 04 Knee Special Tests: Rotary Instability Deck (31):
1

What are the four rotary instability tests?

ALRI
PLRI
AMRI
PMRI

2

What is a rotary instability?

micro-transverse plane rotational instability

3

Why is rotary instability a problem?

due to ACL injuries and subsequent DJD even after good surgeries

4

What are the primary stabilizers of the knee?

ACL
PCL
LCL
MCL

5

In addition to the 4 primary stabilizers, which is another one? What if it's damaged?

ALL
- if it's not present, it must be recreated
- if it's torn, must reconstruct or do a primary repair

6

If the primary stabilizers are lost, what must you rely on?

secondary stabilizers

7

What is the secondary stabilizer of the knee?

capsule
(if this is injured as well, creates even more problems)

8

With a rotary instability, what must remain intact?

PCL

9

PCL in rotary instability

- serves as the axis of rotation
- tibial plateau rotates around the PCL when a primary stabilizer is torn

10

testing position for rotary instability

- same as ant/post drawer
- knee is either in ER or IR, depending on which structures you want to tighten

11

For rotary instability, how do you test lateral structures?

tibia in IR

12

For rotary instability, how do you test medial structures?

tibia in ER

13

direction of force for rotary instability test

- straight sagittal plane
- DO NOT APPLY ROTATION PRESSURE

14

Why should you apply pressure in the sagittal plane for rotary instability?

tibia shouldn't rotate unless it's injured

15

How are the rotary instability tests named?

based on
- tibial plateau that subluxates
- in the direction of applied force

16

What does ALRI test?

- ACL
- middle 1/3 of lateral capsule

17

What movement will occur with a positive ALRI test?

tibial IR

18

What is pathoneumonic for ACL injury?

- Sigund's fx or lateral capsular sign
- menisco-tibial portion fractures because of rotational movement

19

Why are ACL injuries associated with avulsion fx?

because the tibia subluxates forward and violent twisting tears the lateral 1/3 of the capsule

leads to instability

20

common MOI for ACL tears

pivot shift (knee planted with rotation)

21

most to least common rotary instabilities

1. ALRI
2. PLRI
3. AMRI
4. PMRI

22

What does PLRI test?

- posterior 1/3 of lateral capsule
- arcuate complex

23

What does PLRI look like?

tibial ER

24

Devastating injury when the _______ and _______ are both involved

- arcuate ligament
- posterior lateral complex

25

What does AMRI test?

middle 1/3 of medial capsule

26

What does AMRI look like?

tibial ER

27

What is happening with a positive AMRI test?

medial tibial plateau subluxates anteriorly

28

What does PMRI test?

- posterior 1/3 medial capsule
- PMOL

29

What is PMOL?

posterior medial oblique ligament

30

What does PMRI look like?

tibial IR

31

What is happening with a positive PMRI test?

medial tibial plateau subluxates posteriorly