Exam 2 lecture: Knee Flashcards
(118 cards)
1
Q
what is the largest joint in the body?
A
tibiofemoral
2
Q
name the 3 joints that make up the knee joint complex
A
tibiofemoral, patellofemoral, proximal tibiofibular joint
3
Q
what type of joint is the tibiofemoral joint? (simple, compound, complex)
A
complex
4
Q
what type of joint is the patellofemoral joint? (simple, compound, complex)
A
compound
5
Q
what type of joint is the proximal tibiofibular joint? (simple, compound, complex)
A
simple
6
Q
t or f: the tibiofemoral jt is bicondylar w/2 menisci
A
true
7
Q
what joint causes the most patient complaints?
A
patellofemoral
8
Q
t or f: the knee is the most common site of permanent injury in the lower limb.
A
true
9
Q
where are the largest forces in the knee?
A
tibiofemoral joint (posterior compartment) patellofemoral joint (anterior compartment)
10
Q
what separates the femoral condyles?
A
fossa
11
Q
why does the knee have menisci?
A
b/c it needs a variable socket
12
Q
t or f: the femoral condyles are egg-shaped: large posteriorly and small anteriorly.
A
false. the femoral condyles are egg shaped, but large anteriorly and smaller posteriorly
13
Q
why do the femoral condyles have divergent axes?
A
may increase stability of joint
14
Q
what is the significance of the posterior angulation of the femoral condyles?
A
lots of flexion, not much extension
15
Q
which femoral condyle is larger? why?
A
medial b/c of conjoint rotation
16
Q
what muscle inserts on the medial epicondyle?
A
medial hamstring
17
Q
t or f: the medial femoral condyle is more oblique than the lateral femoral condyle (longer from A-P)
A
true
18
Q
what is anteversion?
A
femoral torsion
19
Q
what is the normal range for femoral torsion?
A
10-20˚
20
Q
what is an anteverted femur (degrees)?
A
> 20˚
21
Q
what is a common compensation for anteverted femur?
A
genu valgum
22
Q
what is a retroverted femur (degrees)?
A
<10˚
23
Q
what is a common compensation for retroverted femur?
A
genu varum
24
Q
what is a squinting patella?
A
patella faces medially
25
what happens if squinting patella is uncompensated?
genu varum and toe in
26
what are the possible compensations for squinting patella?
genu valgum
increased external tibial torsion
foot flare
27
t or f: squinting patella + increased tibial torsion --> feet more parallel w/line of progression
true
28
are the tibial condyles concave or convex?
neither; they are flat
29
what are the functions of the tibial spines?
attachment points for ACL and menisci
| stabilizing effect
30
are the tibial articular facets concave or convex?
neither, they are flat.
31
t or f: tibial facets are perfectly round
false. the medial side is larger than the lateral side (egg shaped)
32
what is the significance of the posterior angulation of the tibial condyles?
more flexion ROM
33
what happens if the tibial condyles are broken?
heals w/less angulation --> more hyperextension, less flexion
34
what attaches to gerdy's tubercle?
ITB
35
what type of cartilage lines the patellar surface of the femur?
hyaline
36
what is the main function of the patella?
increase the angular pull of the quads
37
which way does the patellar apex point?
downward
38
which patellar facet is larger?
lateral
39
why does the patella have the thickest cartilage in the body?
highest compression and shear forces in the body
40
t or f: there is more cartilage in the tibiofemoral jt than in the patellofemoral jt.
false. there is more cartilage in the patellofemoral jt than the tibiofemoral jt.
41
what is the Q angle?
represents the pull of the quads; angle is taken from 2 intersecting lines:
ASIS --> center of patella
center of patella --> tibial tuberosity
42
what is the normal Q angle range?
5-15˚
43
t or f: the Q angle is highly dependent on gender
false. the Q angle is more determined by height than gender
44
what is the patellofemoral ratio?
distance from patella to tibia : height of patella
45
what patellofemoral ratio is patella baja? what does patella baja mean?
<0.8; patella too low
46
what patellofemoral ratio is patella alta? what does patella alta mean?
>1.2; patella too high
47
what is the name for a too-large patella?
patella magna
48
what is the name for a too-small patella?
patella parva
49
what are the problems with patella alta?
more likely to dislocate, unstable
50
what are the problems with patella baja?
more stable, can cause abnormal wear and tear
51
what is the ideal patellofemoral ratio?
1 +/- .2
52
what happens to the Q angle during medial/internal rotation of the tibia?
decreases
53
what happens to the Q angle during lateral/external rotation of the tibia?
increases
54
what is the effect of foot flare on the Q angle
increases the Q angle
55
name some situations in which the patella is less stable
```
knee is extended
VMO is weak/stretched medial retinaculum
genu valgum
vastus lateralis or ITB too tight
patella is too small or facel angle is too flat
small lateral lip or shallow groove
patella alta
externally rotated tibia or increased foot flart
excessive foot pronation
```
56
name some situations in which the patella is more stable
```
knee flexed
strong VMO
genu varum
normal patella, patellar groove, large lateral lip
normal or lower patellar position
normal or under pronation
```
57
t or f: compression forces on the patella increase w/extension
false. compression forces increase w/flexion
58
when is there the most force on the patella?
when jumping
59
which direction does the patella glide during flexion?
inferior and posterior
60
t or f: the patella increases extensor leverage more when it is less flexed.
true
61
t or f: the quadriceps force increases as knees flex more (i.e. during squatting)
true
62
VMO or VL responds faster to tension?
VMO (reverse in patellofemoral pain syndrome)
63
why are the anterior compartment ligaments not true ligaments?
b/c they are attached by tendon expansions
64
t or f: a pt with quad rupture cannot extend the knee.
false. pt with quad rupture can still extend the knee b/c of retinacular attachments
65
MR tear + valgus sprain + patellar dislocation = ?
lateral patellar instability
66
t or f: medial and lateral retinaculae have less intense forces on them during flexion/extension activities than the central tendinous band
true.
67
what does the ITB blend with?
lateral retinaculum
68
what are the parts of the ITB?
smaller patellar band
| larger tibial band
69
what happens when ITB is tight?
rubs on lateral femoral condyle
| pulls on patella
70
what are synovial plica?
remnant of 3 embryonic cavities, usually small and asymptomatic
71
what are the common complications of synovial plica?
recurrent snapping and pain
72
what are the functions of the menisci?
deepen socket --> stability and congruency
flexible socket --> accomodate egg shpaed femoral condyles
accomodate slide --> decreased shear stress
decrease compression on articular surfaces (force directed to periphery)
reduce wear and tear
73
how much compressive load does each meniscus transmit to the periphery?
lateral: 70%
medial: 50%
74
what shape is the medial meniscus?
C shaped
75
what shape is the lateral meniscus?
O shaped
76
which meniscus is more often injured?
medial meniscus
77
which meniscus is more mobile?
lateral meniscus
78
why is the medial meniscus less mobile?
b/c of attachment to medial collateral lig.
79
which way to the menisci (and synovial fluid) slide when the knee flexes?
posterior
80
where is stress increased during deep squats?
posterior horns
81
which way do the menisci (and synovial fluid) slide when the knee extends?
anterior
82
when is there more pressure on the menisci?
at full extension (but less focal)
83
t or f: menisci rotate w/tibia
false. the menisci rotate w/the femur
84
which way does each meniscus move during internal rotation?
medial: anterior
lateral: posterior
85
what is the retreating meniscus test
lateral meniscus should move posteriorly during internal rotation
86
which meniscus takes more pressure during internal rotation?
medial
87
which meniscus takes more pressure during external rotation?
lateral
88
what are the effects of varus stress on the menisci?
pinches medial meniscus
| tractions lateral meniscus thru coronary ligs.
89
what are the effects of valgus stress on the menisci?
pinches lateral meniscus
| tractions medial meniscus thru medial collateral lig and coronary ligs
90
which type of stress is more common (valgus v. varus)? why?
valgus b/c lateral leg is more accessible (e.g. via tackle, etc.)
91
t or f: there is potential for injury to the menisci w/any movement
true
92
which are the most common mechanisms of injury to the menisci?
deep flexion
hyper-extension
external rotation
valgus stress
93
what is the old unhappy triad?
medial meniscus, ACL, MCL
94
what is the new unhappy triad?
medial meniscus, ACL, LCL
95
why are menisci poor healers?
not well vascularized
96
how much of the menisci are vascularized?
outer 1/3
97
how do the menisci get nutrients?
from synovial fluid
98
what type of innervation do the mensci have and where?
pain and proprioception @ junction w/deep capsule
99
what are the effects of aging on the menisci?
decreased vascularization
increased wear and tear
increased fragility
100
name the collateral ligs
medial (tibial) CL
lateral (fibular) CL
poplitiofibular lig (post. to LCL)
101
which collateral lig is larger?
medial
102
what are the attachments for the LCL?
lateral femoral condyle, fibular head
103
what type of stress does the LCL mostly resist?
varus
104
what are the attachments for the MCL?
medial femoral epicondyle, medial tibial condyle and shaft
105
what type of stress does the MCL mosty resist?
valgus
106
t or f: medial rotation --> increased stress of collateral ligs.
false. medial rotation --> decreased stress on collateral ligs
107
why is the decreased stress on the collateral ligs during medial rotation significant?
allows conjoint medial rotation
108
what action of the foot would be affected if the collaterals limited medial rotation?
pronation (decreased)
109
does lateral rotation increase or decrease tension on the collateral ligs?
increase
110
what structures make up the posteromedial capsular complex?
posterior part of medial collateral lig.
semimembranosis tendon & tendon expansion
oblique popliteal lig.
111
what is the function of the posteromedial capsular complex?
```
resist hyperextension
resist valgus stress
resist anterior translation
resist extremes of lateral tibial rotation
protect ACL
```
112
what structures make up the posterolateral capsular complex?
```
LCL
poplitiofibular lig
arcuate lig
biceps femoris tendon and tendon expansion
popliteus
```
113
what motions does the posterolateral capsular complex resist?
anterior translation
hyperextension
varus stress
extremes of medial and lateral rotation
114
why does the LCL become lax when the knee flexes?
so it doesnt limit medial tibial rotation and foot pronation
115
what lig is tense during knee flexion?
PFL
116
t or f: PFL is more resistant to anterior translation stability than LCL
true
117
what is the order of ligamentous failure when the leg is extended?
LCL, PFL, popliteus & arcuate lig.
118
what is the most common cause of hemarthrosis?
ACL tear
