MS- knee Flashcards

1
Q
femoral-tibial joint
 type of joint
 motion/ DOF
 accessory motions (2)
A
  1. complex (because of meniscus)
  2. modified hinge joint, dual condylar
  3. does flex/extend (in transverse axis)
  4. accessory motions: rotation and
    aB/aD from valgus force
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2
Q

femoral- patella joint

type of joint

A

sellar joint, modified plane joint

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3
Q

resting position of knee
closed pack position of knee
capsular patter

A

resting position- 25-40deg of flexion

closed pack- max ext (with ER of tibia) screw home mechanism

capsular pattern- lose flex > ext

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4
Q

physiological valgus

anatomy of femur => why favored position is flexion (2)

A

physiological valgus

  1. femoral neck overhangs shaft
  2. femur is angled 5-10 degrees of vertical
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5
Q

articular surfaces of tibial condyle
why favored position is flexion (2)

medial and lateral condyle convexity
relative sizes

A

flexion is favored because…

  1. retroversion of tibial condyles (inclined posteriorly)
  2. retroflexion = tib bent convex for muscle bellies

medial condyle is biconcave
lateral condyle is concave in frontal plane
convex in saggital plane

medial condyle 50% larger > lateral
articular surface 3x thicker > lateral (b/c weight bearing forces and angle of inclination)

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6
Q
femoral condyles
 shape
 relative sizes to each other
       and to tibial condyle
 medial vs. lateral
 WB stresses
A

bi-convex, longer A/P than M/L

2x as long as tibial condyles because of “runner”

medial condyle juts out more and is narrower which allows knee to be horizontal b/c of angle of inclination => better distribution of force

lateral condyle more in line w/ shaft of femur

WB stresses med and lateral equally in double stance

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7
Q
arthrokinematics of knee joint
 sitting down (extension -> flexion)
A

femoral condyles have a “runner” that make it 2x the length of tibial condyle

Ext -> flexion femoral condyles roll posterior w/o gliding, then ACL slides femur anterior

sliding = new points of contact on each bone

** sliding is why its a modified hinge joint*

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8
Q

femoral condyle movements during gait &

how much each moves

A

condyles mostly roll during gait, which is very efficient

lat condyle moves 20 deg
med condyle moves 10-15 deg

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9
Q

knee capsule
superlative

anterior attachements (4)

M/L attachements (4)

A
  1. largest capsule b/c largest joint in our body
  2. has window anterior for patella
attach anterior:
tib
med/lateral tibal condyles
med/lateral patella surfaces
extensor retinaculum

posterior: at level of popliteal notch

med/lateral retinaculum
IT band (not position dependent)
VMO and VL link fascia -> muscle
bicep femoris link fascia -> muscle

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10
Q

ITB relationship to medial collateral

A

IT band adds secondary reinforcement to MCL because they are complete opposite alignments

not postion dependent so maintains tension throughout ROM

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11
Q

Plicae
what is it
3 compartments and whats in them

A

left over compartments from embryological development

3 compartments
1. superior compartment - suprapatellar bursa
2. infrapatella plica (fold) = inferior aspect of femur- filled with fatpad (infrapatellar fatpad)
can become edemaneous mostly in people who work on their hands and knees
flex- gastroc pushed fluid forward so palpable
extend - rec fem pushes fluid back
3. mediopatella plica - palpable

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12
Q

6 knee bursae

names and locations

A
  1. suprapatellar bursa - quad bursa (located in superior plicae)
  2. prepatellar bursa - under skin, anterior to patella
  3. infrapatellar bursa- superficial, anterior to patella ligament
  4. deep infrapatellar bursa- under patella ligament
  5. gastrocnemius - under head of gastroc
  6. popliteus - btwn popliteus and femoral condyle
    these two are hard to differentiate but gastroc bursitis is more common
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13
Q

meniscus
shapes
purposes
vascularity

A

incomplete rings
lateral - ant/post horns closer together => more circular
medial - more half moon shape

purpose: to increase radius of curvature of tibial condyle, distribute WB and decrease friction

inner 2/3 avascular

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14
Q

meniscal transmission of forces
(in flexion and extension)
and what happens if loss of cartilage

A

50% of force in extension
80% of force in flexion

so loss of cartilage =>
increase 2x force on femur
increase 6-7x force on tibia

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15
Q

common meniscal attachments
anterior horns
to tib (2)
to patella (2)

A
  1. intercondylar tubercles of tibia
  2. coronary ligaments (meniscotibial) are comprised of fibers of jt capsule
  3. anterior horns attached to eachother by transverse ligament

attach to patella by

  1. patellomeniscal
  2. patellotibial ligaments (capsule thickenings)
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16
Q

3 lateral meniscal attachements

connections are considered ______ => _______

A
  1. posterior cruciate ligament
  2. popliteus muscle (vis coronary lig & posterior capsule)
  3. femoal condyles

connections are considered loose => less injuries

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17
Q

3 medial meniscal attachements

A
  1. medial collateral ligament -deep fibers
    direct attachement
  2. semimembranous (indirect, thru capsule)
  3. anterior horn from ACL

connections are tight => more tears

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18
Q

unhappy triad of knee injuries

A
  1. ACL
  2. MCL
  3. MM
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19
Q

what happens if you lose degrees of Q angle?

A

Q angle is angle femur makes with middle of patella

if lose degrees of Q angle => increase 50% compression on medial knee

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20
Q

movement of meniscus in flexion and extension

lateral menisci movement vs medial

A

menisci follow point of contact btwn femoral and tibial condyles (pushed by femur)

in flexion => posterior
in extension => anterior

lateral menisci moves 2x > medial

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21
Q

movement of menisci in rotation
in lateral rotation
how do they get injured?

A

lateral rotation: lateral meniscus is pulled anteriorly and medial pulled posterior
because pushed by femur

injured if they dont follow movement of femoral condyles- can become wedge btwn femoral and tibial condyles

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22
Q

patella
shape
facets (#)
purpose

A
  1. triangular shaped
  2. 7 facets, 3 on each side and odd facet
  3. purpose- improve efficiency of extension; increases mechanical advantage of quads by 25%
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23
Q

movement of patella in flexion

ration of patella to patella tendon

A

in flexion patella moves inferiorly 2x its length

patella : patella tendon 1:1

24
Q

patella displacements (4)

A
  1. alta = superior 20% longer tendon > patella
  2. baja = inferior patella 20% > tendon
  3. squinting = medial
  4. bull frog eyes = lateral
25
Q

patella movement on tibia
during medial rotation
during lateral rotation

A

during medial rotation: femur is lateral on tib and pulls patella laterally

during lateral rotation: femur is medial on tib and pulls patella medially

b/c patella is stuck btwn femoral condyles

26
Q

transverse ligament

A

attaches anterior horns of menisci

attached to patella by strands of infrapatellar fat pads

27
Q

MCL
attachements

separate from capsule?

extra important facts about what it blends with

A

medial fem condyle -> upper tib ( posterior to pes anserine)

anterior fibers are separate from capsule
posterior fibers (deep) blend with MM

superficial band blends with posteromedial corner of capsule = posterior oblique ligament = popliteal complex

28
Q

LCL
Location
Part of capsule?
Bands

Purpose (2)

A
  1. Lateral aspect of lat condyle => head of fib
  2. **free of capsule
  3. 3 bands, ant, posterior and middle

Purpose:
Helps prevent lat rotation of tib
Helps ACL prevent hyperext

29
Q

Posterior-lateral support of capsule (4)

A
  1. PCL
  2. Bicep femoris
  3. IT
  4. Popliteus
30
Q

transverse stability… What happens to knee after violent valgus force?

A

knee already had physiological valgus, intense force can => fracture dislocation of lateral tibial condyle and rupture MCL

31
Q

A/P stability of knee
in flexion
in hyperextension

A

in slight flexion: body weight is behind axis so quads are essential

In hyperextension: posterior capsule checks ligamentous stretch and prevents genu recurvatum

32
Q

ACL
direction
max taught degrees
2 bands- when are they taut and lax?

how helpful is it? (%) , when?

A

runs superior posterior and lateral
max taught 0-20 and 70-90

Anteromedial band max tension 70 degrees
Posterolateral band max tension in extension, lax 70 degrees flexion

takes 87% of load with any translation in extended knee

visco-elastic => adjusts to load and length
very rich vascular supply

33
Q

PCL
Direction
Superlative, why is it important
2 bands and when they are max taut

A

runs medial, anterior & superior

strongest stabilizer in knee, 93% of load in extended knee w/ posterior translation

2 bands:

anteromedial: lax in ext, max taut 80- 90 deg flex
posterolateral: taut in extension, lax at 80-90 deg flexion

34
Q

When is flexed knee maximally displaced?

A

75-90 deg flexion

35
Q

Cruciates
relationship to capsule
relative sizes
roles during flex & ext

A
  1. Considered thickenings of capsule
  2. post cruciate 2/3 < ant
  3. during flexion ACL slides femoral condyle anterior
  4. During extension PCL glides femoral condyle posterior
36
Q

posterior capsular ligaments
Posteromedial aspect reinforced by….
Posterolateral aspect reinforced by….
When are they max taut?
What other movements do they add stability to?

A

Posteromedial aspect = oblique popliteal ligament, which is reinforced by tendinous expansion of semi-mem + pes anserine

Posterolateral aspect = arcuate popliteal ligament + bicep fem

All taut in extension
Help valgus and varus stability

37
Q

Rotational stability…
What winds/ unwinds with med/ lat rotation of tibia?
collaterals and cruciates

A

IR unwinds collaterals
ER winds collaterals

medial rotation tightens cruciates (ACL wraps around PCL during IR)
lateral rotation relaxes cruciates

38
Q

Ottawa knee rules
definition
5 things

A

used to determine necessity of ordering x-ray

  1. pt >55 yo
  2. isolated tenderness over fibula head
  3. isolated tenderness over patella
  4. unable to flex knee to 90 degrees
  5. unable to WB immediately and in ER
39
Q

Q angle
normal for males and females
how to measure

A

10-15 degree in males
10-19 in females

0 in flexion** doesnt exist in flexion, must be done in extension (standing)

40
Q

Lachman test
ACL
PCL

A

ACL:
pt supine with slight ER and 20 degrees of flexion
=> testing posterolateral band of ACL

PCL:
pt prone (NO ER) and 20 degrees of flexion
=> testing posterolateral band of PCL

41
Q

Slocum test (2)

A

anteromedial stability-
anterior drawer with 15 degrees lateral rotation

anterolateral stability-
anterior drawer with 30 degrees internal rotation

42
Q
lateral pivot shift test
  pt position
  hand position
  what we do
  positive sign
A
  1. pt supine; hip 20
    knee 5
    abducted
  2. hold behind head of fib and lateral mall
  3. medially rotate tib and add valgus
    • adding valgus will sublux tib
  4. flex knee - ITB will act as flexor and pull tib back in
    hear a clunk
43
Q

hughstons test (2)

A

posteriomedial instability-
posterior drawer with medial rotation

posteriolateral instability-
posterior drawer with ER

“hughston is a pain in the ass” = posterior

44
Q

meiniscal tests

A
  1. tenderness along joint line
  2. squat with feet IR = pain in lateral meniscus
  3. squat with feet in ER = pain in medial meniscus
  4. duckwalk/ childress sign = medial meniscus
  5. McMurrys test for posterior horn
  6. apleys test - either meniscus or ligaments
  7. bounce home test
  8. helfet test = screw home mechanism
45
Q

McMurrys test (2)

A

to test medial meniscus posterior horn:
pt supine, ER, valgus force

to test lateral meniscus posterior horn:
pt supine, internal rotation, varus force

46
Q

apleys test (2)

A
  1. prone, knee flexed to 90, compress and grind knee

2. distract and IR/ER tib to check for ligamentous instability

47
Q

meniscal swelling tests (3)

A
  1. (s)wipe test
  2. patella tap- check for ballotable patella
  3. indentation test- E -> flexion, lose normal indentation around patella
48
Q

plica test

A

flex knee 30 degrees, push patella medially… will feel pain because compressing plica

49
Q

tests for patellofemoral dysfunction (5)

A
  1. quad sets
  2. grinding
  3. clarkes sign
  4. waldron test
  5. fairbanks test- apprehension for patella dislocation
50
Q

causes of patellofemoral dysfunction

A

any time the patells is not tracking correctly in intrapatellar groove => problems on posterior aspect of patella

this can cause erosion of cartilage = chondromalacia

51
Q

referred pain of knee (2)

and what posterior pain usually is

A

L2-L3 - radiate anterior

S1, S2 hip L3- radiate posterior- rare usually anterior knee pain

posterior knee pain is usually bakers cyst- from gastroc or politeus bursa, very visible

52
Q

predictor variables for knee OA (6)

A

must have knee pain + >3 variables

  1. > 50
  2. morning stiffness < 30min
  3. crepitus with active motion
  4. bony tenderness with palpation along joint line
  5. bony enlargement
  6. no palpable warmth (b/c not systemic)
53
Q

McConnell
normal patella alignment
in ext

A
  1. center in groove by 30 deg flexion (resting positon)

2. lateral overhand is okay in extension

54
Q

according to McConnell… forces acting on patella
lateral (3)
medial (2)

A

lateral:
lateral retinaculum which blends with
ITB
vastus lateralis

*usually tight lateral side

medial side:
medial retinaculum
VMO

55
Q

factors affecting patella alignment (McConnell) 6

A
  1. increased Q angle
  2. tight lateral structures
  3. tight gastrocs or hamstrings
  4. excessive pronation of foot
  5. patella alta (high patella = long tendon)
  6. VMO insufficiency
56
Q
patella movement terminology and nomenclature
 glide
 tilt
 rotation
 anteroposterior
A

glide- M -> L
tilt - around Y axis
named for lower side/ side its tilting to
rotation- inferior pole around z axis
named for direction of inferior pole
L most common
anteroposterior- inferior pole around x axis
named for inferior pole
posterior most common

57
Q

McConnell treatment of PFP

A
  1. stretch tight lateral structures (before taping)
  2. patient self stretch
  3. passively position with tape