Lecture 7 - Knee Flashcards

1
Q

what bones make up the true knee joint

A

Tibio-femoral joint is formed by
- femur (condyles)
- tibia (tibial plateau)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Movements at the knee joint

A
  • flexion
  • extension
  • internal rotation (tibia)
  • external rotation (tibia)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

muscles that make up the quad

A
  • rectus femoris
  • vastus lateralis
  • vastus medialis
  • vastus intermedius
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

muscles that make up the hamstring

A
  • semitendinosus
  • semimembranosus
  • bicep femoris
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what muscle unlocks the knee

A

popliteus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

pes anserine

A

acts as a secondary valgus restrainer, augmenting the medial support of the knee
* muscles that are attached to the pes anserine are the:
- gracillis
- sartorius
- semitendiosus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Ligaments of the knee

A
  • Anterior cruciate ligament (ACL)
  • Posterior cruciate ligament (PCL)
  • Medial collateral ligament (MCL) most commonly injured
  • Lateral collateral ligament (LCL)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is joint line tenderness (JLT)

A

physical examination test commonly used to screen for sensitivity related to meniscal injuries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

lateral meniscus

A

Lateral meniscus
- almost circular
- consistent in width throughout
- more mobile
- anterior end attaches to intercondyloid portion of tibia, behind ACL (blends with ACL)
- posterior end
posterior ends attaches to intercondyloid portion of the tiba

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

role of meniscus

A

increase joint congruency; act like a suction cup
- some cushioning effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

medial meniscus

A
  • more like a half moon/semicircular fibrocartilage band
  • bigger
  • anterior portion is attached to the lateral meniscus via the transverse ligament
  • attached to the tibia via meniscotibial ligaments
  • posterior end attaches between the PCL and lateral meniscus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

epidemiology of knee injuries

A
  • 40% are ligamentous injuries
  • most common injury is MCL, followed by patellar tendon, ACL, meniscus, LCL, then PCL
  • females more commonly injure their knees compared to males
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Steps of initial examination of the knee

A

History
- previous injury knee injury? MOI; does it feel the same as last time you injured it
Observation
- deformity, swelling (swipe test), discolouration
ROM
- active, passive, resisted
Manual muscle testing
Palpations
- point tenderness of ligaments may be a good indicator of which structures are injured
Special tests
Functional assessments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

mechanism of an ACL sprain/tear

A

hyperextension, plant and twist (sounds like a loud snap/pop)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

S/S of an ACL sprain/tear

A
  • pain (depends on the degree) location can be: posterior, below the patella, lateral/anterior, extreme
  • swelling (in first 24hrs; consider middle genicular artery)
  • decreased ROM and strength (depends on the degree)
  • altered gait
  • feels very unstable
  • hamstring goes into spasm with this injury; hanstring goes into protection mode and helps the tibia to not translate anteriorly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

mechanism of an MCL sprain/tear

A

valgus force (intrinsic/extrinsic), tibial rotation force

17
Q

S/S of MCL tear/sprain

A
  • medial knee joint pain
  • pain with full extension/flexion
  • mild inflammation/swelling
  • decreased strength/ROM
  • altered gait patterns
  • feeling unstable medial
18
Q

why do quads atrophy when you tear your ACL

A

arthrogenic muscle inhibition (AMI) at the cortico level (brain tells muscle to do this)
- AMI is defined as a lack of extension due to quadriceps inhibition and hamstring contracture

19
Q

mechanism of a meniscal tear

A

landing and twisting, planting and twisting (foot fixed); sometimes hear a tearing noise

20
Q

S/S of a meniscal tear

A
  • pain with weight bearing
  • catching or clicking noise
  • locking or give out of knee
  • altered gait pattern
  • swelling (minor/sever; depending on tear)
21
Q

mechanism of an LCL sprain/ter

A

varus force (intrinsic/extrinsic), tibial rotation force

22
Q

S/S of LCL sprain/tear

A
  • lateral knee joint pain
  • pan with full extension or flexion
  • mild inflammation/swelling
  • decreased strength/ROM
  • altered gait pattern
  • feeling unstable laterally
23
Q

why is there more instability when you tear the LCL then when you tear your MCL

A

there aren’t as many muscles attaching to the lateral aspect of the knee (consider the pes anserine)

24
Q

mechanism of a PCL/Posterior capsule sprain/teat

A

landing with knee extended, extrinsic force causing hyperextension

25
Q

S/S of PCL/Posterior capsule sprain/tear

A
  • posterior knee pain
  • posterior swelling
  • pain with full extension
  • decreased strength and ROM
  • poor control of hamstring preventing extension
26
Q

what tests you use to test for injuries/sprains/tears of knee structures

A

ACL - anterior drawer test
PCL - Posterior drawer test
MCL - valgus challenge
LCL - varus challenge
Meniscus - Thessaly’s

27
Q

what are the injuries that make up the unhappy (terrible) triad and why is this injury bad

A

Medical meniscus tear
MCL tear
ACL tear
- can cause tibio-femoral separation (like a door hinge)

28
Q

how do you manage an unhappy triad injury

A
  • RICE
  • taping and bracing
  • ROM
  • strengthening
  • balance
  • functional/sport specific exercises
  • RTP
29
Q

what is a check rein

A

reinforced taping to prevent movement

30
Q

is knee taping or knee bracing more effective

A

bracing

31
Q

what to do if we suspect a knee fracture

A

OTTAWA KNEE RULE
x-ray knee if…
- bone tenderness with palpation of the head of the fibula
- isolated bony tenderness of the patella
- inabillity to flex knee to 90 deg
- 55 or older
- inability to weight bear for 4 steps immediately and in ED

32
Q

why do we use ottawa knee rule

A
  • evidence suggests useful to rule out fracture
  • sensitivity of 98.5%
    *decreases unneeded x-rays and saves time
    WE DON’T WANT TO MISS FRACTURES