the knee Flashcards
1
Q
purpose of knee
A
allow bending to clear foot during gait, to lower the body and COM and to transfer forces
2
Q
what stabilizes the knee
A
muscles, ligaments, and mensci provides stability
3
Q
what are the 3 facets
A
medial, odd, and lateral facets
4
Q
top of patella
A
base
5
Q
bottom of patella
A
apex
6
Q
true or false: medial facet is larger and has a larger meniscus
A
true
7
Q
Femoral/tibial condyles
_____ ________is not concave in all areas - slightly convex in some areas
A
tibial plateau
8
Q
____ _____ is steeper and higher on lateral side to protect form lateral dislocation
A
femoral condyle
9
Q
true or false: femoral condyle is smaller than tibial condyles (poor congruence)
A
false: femoral condyle is larger than tibial condyles
10
Q
what helps with screw home mechanism
A
the curve of medial condyle
11
Q
what is Q angle
A
its the angle between femoral and tibial shaft - male is 12 degree and female is 16 degree
12
Q
is it normal to have a mild gene valgum and why?
A
extension of the femoral condyle and hip angle of inclination
13
Q
increase of q angle will cause
A
increase of gene valgum
14
Q
the importance of synovium
A
it projects inward to exclude the ACL/PCL form the synovial cavity, so they are intra-articular but extrasynovial ligaments
15
Q
what communicates with the joint cavity
A
supra patellar bursa
16
Q
what is a vestigial remnant of mesenchymal tissue - not uncommon, but not considered normal
A
plicae
17
Q
true or false: plicae can also be normal folds in the capsular tissue that just become pathologically thickened
A
true
18
Q
plicae can remodel over time, but may not, and when it remains, it can become ____ and cause friction related pain from rubbing on articular cartilage
A
thickened
19
Q
true or false: if you have plicae it is common have it surgically removed
A
true
20
Q
name the main three bursa
A
infra patellar bursae
prepatallar bursae
suprapatallar bursae
21
Q
purpose of infrapatellar fat pad - what could happen after surgery
A
protection; can get impinge
22
Q
true or false: you can get as many as 13 bursae
A
false: 14
23
Q
what is Hoffa Syndrome
A
the scarring after a BPTB graft and there’s impingement on the infrapatellar fat pad. impingement of the joint that causes pain
24
Q
purpose of ligaments and tendon
A
stabilize and guide arthorkinematics
25
tendons actively ____ osteokinamtic motino
induce
26
ligaments, capsule and retinaculum passively ___ arthrokinematics
guide
27
MCL has
superficial and deep fibers
28
purpose of superficial fibers
provide major restraint to values forces at the knee
29
true or false: MCL is more taut in full flexion
false: full extension
30
Deep fibers of MCL is more often injured due to?
they experience more than 20% stretch so they are usually injured more frequently
31
collaterals can stretch ____ normally
20 percent
32
description of Lateral collateral ligament
extra capsular, feels ropy, or like a pencil, major restraint to arms force at the knee
33
ACL is taut in
EXTENSION
34
PCL is taut in
flexion
35
AM and PL buddies are parallel, so both are fairly taut. in flexion, AM bundle is ____ and PL bundle is ____
taut, loose
36
true or false: it is difficult to mimic both bundles in grafts, so the repair is never quite the same as the original
true
37
why does curates don't heal on their own
they are bathed in synovial fluids and it washes away any clotting that occurs
38
intracapsular but extrasynovial - posterior invagination of the synovium excludes the ______ ______ from the synovial cavity
cruciate ligaments
39
purpose of menisci
reduce stress, disperse force and provide proprioception
40
menisci compress and bulge; tear causes _____ of hoop stresses
loss
41
MOI of menisci
forceful, axial rotation of the femoral condyles over partially flexed and weight bearing knee
42
lateral tibial articular surface is ____ to _____. medial is ___
flat to convex
concave
43
meniscal attachments to the tibia is known as ____
horns of menisci
44
purpose of coronary ligaments
provide further mescal attachment to tibia (can mimic meniscal tear when irritated)
45
quads and hamstrings send slips to the menisci to
move them during motion to match position of femur
46
coronary ligament are loose to allow for ____ ______
meniscal movement
47
transverse ligament connects the two menisci and prevents ____ _____ of the anterior horns
anterior translation
48
transverse ligament connects the 2 _____
menisci
49
true or false: medial menisci is greater than lateral menisci
true
50
medial meniscus attached to capsule and therefore to MCL; lateral meniscus attached to capsule only therefore LCL is
extra capsular
51
valgus force to lateral side sprains
MCL and tears meniscus via coronary/capsule/MCL connections to ligament
52
medial meniscus covers smaller percentage of tibial plaque - more direct contact femur/tibia resulting increase of ____-
OA
53
true or false: medial is more resilient and lateral is more likely to get injured
false: lateral is more resilient and medial is more likely to get injrued
54
other third of the menisci gets more blood but you move inward you lose vascularization meaning?
less blood flow
55
passive stability:
oblique popliteal ligament reinforces the posterior capsule
56
active stability:
popliteus
57
cause of evolute
shapes of bone, cartilage and menisci, as well as pull of ligaments at different degree of motion
58
tibia on femur
OKC
59
femur on tibia
CKC
60
screw home mechanism OKC:
Tibial ER on fixed femur during full extension - flexing will unlock it (IR of tibia)
61
screw home mechanism CKC:
Femoral IR on fixed tibia during standing (full ext) - squatting (bending) will unlock it (ER of femur)
62
what are three factors that causes screw home mechanism
- shape of medial femoral condyle
- tension in ACL
- Lateral pull of quads
63
screw home is called conduct and does not occur during isolation. when does it occur?
during extension and releases during flexion
64
What does screw home mechanism help with?
improves congruency and stability in extension (standing)
65
what muscle best facilitate the unlocking of knee flexion and rotation
popliteus
66
which meniscus moves farther and why?
lateral moves farther because its not attached to LCL - therefore its more mobile
67
what happens to the menisci during femoral roll in flexion?
moves posteriorly
68
what happens to the menisci during femoral roll in extension?
moves anteriorly
69
what muscle are taut in flexion?
PCL
70
what muscles are taut in extension?
- ACL
-MCL
- oblique popliteal ligament
71
most ligaments get more loose in ______?
flexion
- ACL, MCL, Posteromedial capsule, oblique popliteal ligament, LCL
72
what happens if you have a loss of ACL?
loss of majority of knee stability
73
what muscle provide a posterior glide of the tibia in which it helps with protecting the ACL
hamstrings
74
_____ provides 85% of passive resistance to anterior glide
ACL
75
MOI to ACL
foot paneled, large valves force, axial rotation either direction, hyperextension (can also be flexed)
76
why does cruciate ligament not heal on its own?
bathed in synovial fluid
77
why does ACL not regain full strength and function after torn?
takes time for graft to revascularize and goes through necrosis until vascularization is complete
78
true or false: women is 5x higher at risk for ACL tear compared to males
true
79
reasons why ACL are higher risk of ACL tear?
- smaller ACL, wider pelvis, increase in Q angle
- hormones - estrogen
- neuromuscular control- lack of ability to control dynamic valgus
-stiffer landing form jump
- less muscle mass or strength
- greater quad/ham ratio on lading
80
PCL is taut in?
flexion
81
what muscle is the secondary restraint if PCL is ruptured
popliteus
82
true or false: PCL is thinner than ACL and injured more frequently
false: PCL is thicker and injured less frequently
83
MOI of PCL
dashboard injury
84
patella is ____ on femur in flexion but _____ in extension
- inferior
- anterior
85
patellofemoral (patella) - in flexion the pull the quads and tendons causes?
higher JFR
86
greatest patellofmeroal contact comes at what degrees?
60 to 90 degrees
87
in full extension, out of the groove, apex of the patella has the most contact what should you avoid?
avoid exercise if pain is at the apex or inferior pole
88
at 90 degree of the patella, the contact is more at the base of the patella, and you're having pain near quad tendon, which position should you avoid exercising?
avoid exercises that are in deeper flexion
89
patellofemoral motions: three axes of motion
- tilt
- flex/ext
- spin
90
medial lateral tilt of the patellofemoral happens in what axis
vertical axis
91
nodding and shift (flexion/extension) of the patellofemoral happens in what plane
sagittal plane
92
spinning of patellofeoral happens in what axis
z axis
93
the actual motion oof patellofemoral motions is included by
shape of notch, femoral position (rotation) , and tension in reticular fibers
94
function of the patella
space sesamoid bone that increases MA - MA greatest at 20-60 degree of flexion
95
3 factors determine MA
- shape and position of patella
- shape of distal femur
- migrating medial/lateral axis
96
patellectomy
patella increase strength of quads so more force required todo same task without patella
97
compressive force (with an equal and opposite patellofemoral JRF)
determined by quad force and joint angle
98
why is compressive force higher as the squat gets deeper?
patella is interposed with extensor mechanism, so patellar tendons dan quads pull in opposite direction causes a compressive force that increases with flexion in CKC
99
different compressive forces on PFJ with different activities (walk vs SLR vs starts vs deep knee bend)
- walking: 1.3x
- SLR: 2.6x
- Stairs: 3.3x
- Deep knee bend: 7.8
100
why is SLR Cf higher than walking?
due to high quad force in full extension OK plus smaller particular contact, so force is focused on smaller area
101
PFPS
patellofemoral pain syndrome - most common knee pathology treated in PT
102
best positions to do exercise to reduce PFJ stress :
0-45 degree CKC, 90-45 degrees OKC
103
patellar tracking is affect by
muscle pull, ITB, retinaculum
104
quad pulls ____, _____ ,and ___
- laterally
- posteriorly (stabilizes but also compresses PFJ)
- medially
105
vastus lateralis oblique has a _____ PCSA, which can lead to _____ tracking
large
lateral
106
normal range for q angle
13-15
107
ITB can pull patella ______
laterally
108
purposes of posterior pull
stabilization, especially in full extension, when patella is out of the groove
109
local factors in pathologic lateral patellar traciking
- bowstringing and q angle
- ITB
- lateral patellar fibers
110
mitigating force
- CMO
- lateral femoral condyle
- medial reticular fibers; medial patellofemoral ligament
111
global factors in pathologic lateral patellar tracking
- anything that places knee in valgus or medial axial rotation extreme or shallows the groove will case lateral tracking
112
what could cause more bow straining
increased valgus, coxa vara, pronated feet, hip abudctor weakness, ER weakness, IR tightness
113
surgery for patellar tracing
treatment will focus on minimizing scarring restrictions, correcting faulty mechanics, restoring functional strength/ROM
114
muscle extensors
VL, RF, VML, VMO
115
___ produce 80% of torque, ___ is other 20%
Vasti, rectus femoris
116
what attach to menisci
lateralis and medialis attach to the menisci
117
what has the largest x section
lateralis
118
what projects farther distally
medialis: two fibers - longus and obliquus
119
what pulls anterior capsule
articularis genu
120
deep fibers of the vast are attached to capsule and keeps the capsule from getting _______ in _______
impinged in extension
121
different pulls of the quadriceps muscles helps with
stabilization and medial stability to counteract lateral subluxation/dislocation
122
extensor function
isometric
eccentric
concentric
123
normal quad and hamstring ration
50-80 % and lower in females
124
extensor function - isometric purpose
stabilization
125
extensor function - eccentric
controls rate of descent of COM, shock absorption, extent of flexion, dampens impact of loading - deceleration; force dissipation; shock absorption
126
extensor function - concentric
accelerates tibia or femur toward extension, raise COM - acceleration propulsion
127
external torque against extensors - torque in OKC
increase from 90 to 0 deg (most in full ext, least in flexion)
128
external torque against extensors - torque in CKC
decrease from 90 to 0 (most in deep squat, least in standing upright)
129
trade offs-
CKC more functional and more joint congruence, but also more JRF
OKC less functional, less congruent, but less likely to increase JRF
130
max internal torque is greatest at
around 45 deg (max leverage due to longest moment arm)
131
why is max torque between 3-80 degrees when max leverage is 20-60 degrees
leverage depends only on moment arm , torques also condor force and distribution of mass
132
3 areas to consider internal torque
- MA (leverage)
- CSA
- length tension - number of cross bridges
133
function - what arc of motion is where most functional activities re performed
squats
sports
sit to stand
134
true or false: internal torque is smallest at full extension
true: greatest at 20-60
135
in flexion, quads have superior line of pull and hamstrings pull posterity so both are redoing _____.
ACL strain while stabilizing joint
136
with extension, get anterior translation of tibia on femur (strain on graft) - flexion protects
graft
137
co-contraction of ____ can help mitigate glide of tibia
hamstrings
138
what is extensor lag
internal torque decreases to minimum - just as external torque is at maximum
- weakness of quad - causes inability to extend fully
139
muscles of flexors/rotators
hamstrings
sartorius
gracilis
popliteus
gastroc
140
which muscle is the key to unlock screw home mechanism through flexion and rotation
popliteus
141
IR of ___ on femur in OKC - screw home mechanism
tibia
142
ER of ____ on tibia in CKC - screw home mechanism
femur
143
true or false: popliteus is the only rotator in extension with good leverage and stability for unlocking the extended knee ( other rotators have but leverage at 70-90 deg flexion)
true
144
gastric only ____ the knee
flex
145
rotation is most free with ___
flexion
146
rotation with extension is near ____ - only comes from hip
zero
147
during swing phase, is tibia on femur or femur on tibia?
tibia on femur
148
purpose of concentric quad into extension during gait
accelerate and lift during the swing phase of gait
149
purpose of eccentric hamstrings and hip extensors
decelerate during terminal swing of gait
150
contraction of vast stretches distal semitendonisus: purpose of this is to?
- store entry to help with hips extension effort of proximal semitendinsosus and glute max
- slows contraction velocity creating higher force production
151
semitendinosus is _____ = transfers energy from contracting vast to extending hip
transducer
152
concentric quad =
stretch of HSs
153
low contraction of HS =
high force production
154
glute max contraction =
stretch of rectus femoris
155
patients with glute weakness tends to do what during their gait to compensate for their weak hip extensors
lead backward
156
leaning backwards decreases hip flexion moment which results in?
causes less load on glute max and hamstring
157
backward leaning will have an increases in knee flexion moment by brining the GRF further behind the knee axis resulting in
increases load on quads to maintain knee extension - increases load on patellofemoral joint, leading to OA and/or uses
158
backward lean causes increase of the ankle plantar flexion moment by bringing GRF behind ankle axis results in
increases load dorsiflexors
159
why does medial compartment have more incidence of did?
GRF is medial to knee and causes various torque or moment.
- also doesn't have as much freedom as lateral compartment, and it is more exposed due to C-shaped medial meniscus
160
true or false: virus increases medial compression
true
161
causes of valgus deformity
coxa vara, obesity, stretched MCL, genetics, mm weakness(foot)
162
symptoms of valgus collapse
- lateral hip stress
- anterior hip impingement
- ITB stress
- weak glutes
- MCL strain
163
genu recurvatum and treatment
weakness of hamstrings - stretches posterior capsule/ligaments and the problem keeps getting worse
treatment: strengthen HS, bracing, heel lifts
164
osgood schlatter's
ensthesis issue (patellar tendon pulls its bony attachment away from the tibia, new bone growth fills the gap
165
tenonditis
true inflammation, swelling
166
tendinitis/tendinopathy
chronic pain with no signs and symptoms of inflammation
167
bakers cysts
ballooning of post joint capsule - irritation of bursa between gastric and semimembranosus
168
PFPS
anterior knee pain - patellar tracking, abnormal joint mechanics, overuse, mobility issues, neuromuscular control issues, mm weakness
169
chondromalacia patella
softening/breakdown of retropatellar cartilage (usually due to disuse)
170
unhappy train
ACL
MCL
medial meniscus
