basic science Flashcards
(243 cards)
1
Q
receiver operator curve
A
true positive (1-Sp) on y-axis; false negative (1-Sp) on x-axis
2
Q
confirmation bias
A
when surgeons recall studies that prove their treatment and forget contradictory evidence
3
Q
pelvic incidence and lordosis
A
PI - LL should be LESS THAN 11
4
Q
Lesch Nyhan syndrome
A
severe MR; SELF MUTILATING/AGGRESSIVE; severe progressive scoli; wheel chair bound; hib sublux/dislocation is very common
5
Q
gene for Lesh Nyhan
A
- x-link rec; males; hypoxanthing guanine phosphoribosyl transferase (HPRT) - needed for purine metabolism
6
Q
deficiency in morquio syndrome
A
n-acetylgalactosamine 6- sulfate sulfatase
7
Q
deficiency in hurler
A
alpha L iduronidase;
8
Q
deficiency in gaucher
A
beta gluccocerebrosidase
9
Q
degnen disc disease has what effect on chondrocytes
A
apoptosis
10
Q
order of inflammatory cytokines
A
IL 1 B; TNF alpha; then Nitric oxide and MMP’s
11
Q
what is min brace hrs/day for 90%success in AIS
A
12 hours - success defined as avoiding surgical threshold of 50 deg
12
Q
what is inducible resistance in MRSA
A
a plasmid changes resistance via 50S ribosome ; seen in eryhtromycin resistant strains - causes resistance to Clinda - use a D-Zone test to rule this out
13
Q
type 1 error is a
A
false positive - reject the null when you should accept the null
14
Q
osteocalcin made by
A
osteoblasts; attracts osteoclastss and is abundant in matrix; regulates mineralization and bone denisity
15
Q
fibrillin gene defect does what in marfans
A
alters binding of TGF b and leads to high levels in tissue - causes the aortic root dilitation
16
Q
gymnasts wrist occurs at which part of physis
A
zone of prov calcification - generally repetitive loading stress occurs here as it interferes with metaphyseal perfusion - may see physeal widening from active hypertrophic zone
17
Q
how do thiazolidinedione meds work
A
activate PPARy to differentiate mesenchymal cells towards fat cells - down regulate osteoblastic transcription factors leading to increased fracture risk
18
Q
what is the pathophys of MHE
A
defect in heparin sulfate which leads to poor chondrocyte organization and dev of exostoses
19
Q
drug elution time for vanc/tobra in cement
A
4 months
20
Q
what is condition with ACVR1 gene defect
A
fibrodysplasia ossificans (stone man)
21
Q
tx of infantile hipdysplasia without dislocation
A
pavlik if US shows low alpha angle
22
Q
what does BMP 2 do
A
in inflammatory phase of bone healing it recruits mesenchymal stem cells
23
Q
best approach for talar neck fractures
A
2 incision med/lateral with med mal osteotomy if needed
24
Q
time dependent vs concentration dependent abx
A
vanc is time dependent -needs good trough dosing b/w doses; gent is concentration dependent
25
what is lubricin in joints
NOT part of cartilage matrix but MADE by c-cytes - glycoprotein to reduce friction
26
Anakinra blocks which cytokine
IL-1
27
what is fretting corosion
micromotion between two metals that are NOT loose
28
crevice corrosion is
affects oxygen tension due to micromotion disrupting the passivation layer
29
fisher test is for
categorical variable for SMALL numbers of data
30
Chi-Sq test is for
categorical variable for LARGE numbers of data
31
which two tests are for comparing categorical data
Fisher for small; chi-sq for large
32
Unpaired t test is for
continuous data
33
extrinsic vs intrinsic tendon healing
extrinsic is FASTER but MORE adhesions
34
how does primary bone healing occur at midpoint
osteoclasts and blasts invovled in remodeling of lamellar bone - OC use cutting cones; OB lay down new bone behind
35
what med helps spinal fusion in osteoporotic
teraperatide
36
best mdium for kingella growth
blood agar
37
kingella is gram
negative
38
time of sx before presentation kingella
9 days
39
what is granada agar used for
to isolate group B strep
40
what happens to disc during degeneration
increase Colllagen 1, and NON-enzyme x-links (this process increased adv glycation end products); Collagen 2 DECREASES;
41
increased cross linking in UHMWPE does what
decreases wear and decreased TOUGHness
42
how is primary bone healing accomplished
haversion remodeling
43
what enzyme is responsible for tumor invasion
MMPs - breakdown basement layer and interstitial stroma
44
what modality is BEST for detecting physeal bar
T1 MRI - bc wil show unossified bars too
45
Injury to what zone of physis causes growth arrest
resting zone - closes to epiphysis
46
what is order of zones of physis
epiphysis - resting > proliferation > hypertrophic (maturation, degen, provisional calicifcation) > metaphysis
47
where do most physeal fractures occur
in hypertrophic zone bw Provisional Ca and metaphysis
48
how to manage peds growh arrest from distal radius
simple bar - excise and fat; if small arrest in teenager epiphysiodesis of ulna is enough if asymptomatic) ; if large - corrective osteotomy
49
what is fatigue wear
progressive mechanical use and result of repetiive cyclic loads
50
post trauma ankle OA has similar impact on QoL as
ESRD and CHF_
51
pagets gene mutation
5q35-qter - ubiquitin binding protein sequestosome 1
52
what effect does motion have on tenon healing
collagen ORGANIZTION more than production
53
what condition shows tgf-beta excess
marfans
54
what is oncogenic osteomalacia
seen with osteoblastoma, fibrous dysplasia; and fibromas - FGF23 excess leads to poor phosphate resorption in kidneys and inhibits 1-alpha hydroxylase (low Phos and low 1,25 vit D)
55
what is pathogenisis of atlantoaxial sublux in rhA
Transverse lig becomes incompetent and Anterior ADI is wide
56
polylactic vs polyglycolic acids
used to make resorbable implants - PG has higher stiffness and resorbs FASTER 6-12 months vs 24 months for PL
57
what embroynic structure forms the disk
sclerotome
58
best stain for cartilage
safranin O and alcian blue
59
what is mode of failure for interference screw
graft tear, pull out or slippage
60
what is equation for number needed to treat
1/Absolute risk reduction
61
best mri for acute trauma
STIR - better than T2 bc STIR will supress fat and marrow edema
62
what is result of excess muscle-ski motion at ex-fix pin
increased inflammation and thus more pin site infections
63
how to double ex-fix pin stiffness without changing pin
bury the shank in proximal cortex
64
what is effect of HA coated ex-fix pin
improves pin/bone interface but INCREASED extraction torque
65
osteoclasts staining via
cathepksin K stain or TRAP
66
increased pin spread does what to a ex-fix
increased stability
67
in compression plating which screws get max stress
those FURTHEST from fracture - this is opposite of bridge plating
68
how to improve torsional strain in plate
4 screws on either side; no more improvement after 4
69
best rigidity construct for bridge plate
lowest working distance, and one more screw close to fracture, then one far away - like ex-fix
70
what is definition of frailty
decreased physio reserve and inability to respond to stressors
71
if you see peroneal tendon with third tendon
excise- p. quartus
72
growth factor timeline in masquelet
peak at 4 weeks; baseline at 6 months
73
where does artery of adamkiewc originate
T8-L1
74
what perecent of patients have lasting sx from plexus injury after lateral spine surgery
< 5% at 1 y; but start with up to 34% with LE weakness
75
what is ant retractor up against during post approach
psoas
76
what is distal limit of ant hip approach
femoral NERVE
77
risk of MRSA colonization
higher in blacks; lower in adv age and females
78
main risk of haringe approach to hip
Sup gluteal NERVE (not artery)
79
how do osteoblasts affect immute system and Hematopoitic cells
jagged1 - notch pathway
80
HYPERcoagulopathies
MTHFFR gene has highest risk; Factor V leiden; Proten C and S deficiency, Protein C resistance, elevated factor VIII (opposite of hemophilia)
81
conditions that increas risk of DVT
pregancny, cancer, OCP, hormone tx
82
what counterintuitive hypercoag state occurs after starting warfarin
rapid rise in INR after unopposed warfarin in post-arthroplasty - has to do with rapid consumption of protein C
83
other names for thromboplastin
TF, Platelet TF, CD 142
84
which shoulder arthroplasty patients get LMWH
if higher risk and not mobilized; ASA and antiplatelet alone is NOT enough
85
what E source after 4 min of aerobic
glycogen and FA
86
when is ATP used
first 10 seconds of anaerobic
87
avulsion 5th MT jones frx tx
SURGERY
88
osteophyte formatio pathway
IHH stimulates chondrocyte differentiation - leading to endochondral ossification
89
abatacept MoA
blcoks T-cell activiation via MHC
90
how does L5 root get injured in L5-S1 fusion
lateral exit of Sacral screw heading towards ALA
91
case series is what L of evidence
4; also includes poor quality cohort studies or case control
92
sarcomere units
A band is myosin section; I band is actin filament; H band is area with NO acitin myosin overlap; z band bisects I band
93
what is osteonectin
glycoprotein that is secereted by osteoBLASTS and binds to calcium - therby regulating mineralization
94
annulus fibrosis is derived from
mesoderm
95
osteoblast pathway for immune regulation
via PTH to jagged (osteoblast) notch (h-poeitic cells)
96
what is role of BMP 2
chondrocyte differentiation pathway for mesenchymal cells
97
which BMP is osteoinductive
5,6,7,
98
what is BMP 1
MMP for propreptidase 1,2, 3 collagen
99
refractory osgood schlater treated with
resection of TT OSSICLE ONLY - does not involve patellar tendon
100
deficiency in heparin sulfatase
san fillipo syndrome
101
beta galactosidase deficiency leads to
morquio
102
morquio defect
beta galactosidase deficiency
103
systematic review of RCT and level 2 studies is overall
level 2
104
tibial tubercle ossification and fusion
11 and 14 ossify (F, M); and 14 and 18 fusion
105
cathepskin K inhibtor works to decrease which cells activitiy
osteoclasts
106
what is start of common pathway for coag
X to Xa conversion which leads to conversion of prothrombin to thrombin
107
what does aspirin block
Thromboxane A2
108
the Xa inhibitors
Fondaparinaux(indirect); Apixaban and Rivaroxiban (direct)
109
which zone of cartilage has least proteoglycan
superfiical
110
what fixation method is at risk for pull out
staple
111
what fixation method is at risk for breakage
transfixtion pin
112
what fixation method is at risk for cortical bone pull through
cortical button
113
golgi organs purpose
relay muscle tension and length, proprioception
114
pacinian corpuscles relay
deep pressure and vibration
115
ruffini ends conve
sustained presure sensation
116
merkel cells convey
sustained touch and pressure sensation
117
decorin protein role
regulates collagen fiber size (decorates with diff collagen sizes)
118
osteocalcin requires
vitamin K and is a gamma carboxylation of glutamic acid
119
gene assay tests
PCR -DNA; northernblot and RT PCR - RNA level; and Western blot is for protein
120
freeze dried vs frozen allografts
freeze dried have same compression and tensile strength; but less torsional and bending
121
does frozen graft have osteoinductive potential
yes limited; and has osteoconductive; lasts 1-5 years
122
quad weakness leads to what during swing phase
knee hyperextension; hip flexors rapidly contract to flex femur and then gluts rapidly contract to slow femur - as a result tibia swings forward and hyperextends
123
what is needed to maintain articular cartilage phenotype
PTH-RP
124
role of aggreca
exerts swelling pressure against restraint of collagen
125
what does type 6(VI) collagen do
mechanical signaling to chondrocytes
126
how does clonazepam increase osteoporosis
does NOT interfere with vitamin D BUT can increase sclerositin levels and therby decrease osteoblast
127
max length for nerve conduit
3cm
128
order of nerve function return
sympathetic, pain, temp, touch, proprioception, motor
129
where do obturatator arter and sup gluteal arise
INTERNAL iliac
130
general muscle fiber type
slow oxidative (type I), fast oxidative-glycolytic (type IIA), and fast glycolytic (type IIB)
131
Type I fibers
type 1 smaller and contract more slowly and less forcefully but are fatigue resistant. Type IIA is intermediate, type IIB is fastest most powerful but most fatigue-prone myofibril type.
132
definition of specificity
probability that negative person will test negative - TN / FP + TN
133
lab values in type 1 Vit D Rickets
low ca, low phos, low 1,25, high ALP, PTH
134
lab values in type 2 Vit D Rickets
low Ca, low phos, HIGH 1,25, HIGH ALP and PTH
135
x linked hypophosphatasia
low PO4; NORMAL CA; ALP high, NORMAL PTH, LOW VIT D 1,25 - bc kidneys can resorb phosphate
136
where does scfe happen
maturation zone of hypertrophic zone
137
where does scurvy and corner fractures occur
zone of provisional calification
138
what conditions affect the reserve zone of physis
Gauchers and Diastrophic Dysplasia
139
rifampin affects
RNA polymerase
140
CaSo4 vs CaP04
phosphate is stronger; BOTH are wear to shear and torsion
141
non nitrogen containing bisphos have
ATP analog that causes apoptosis of osteoclasts etidronate, and clonodrate
142
power equation
1- type 2 error (beta)
143
what makes a RCT level 2
follow up less than 70%
144
what is Rh factor
IgM against the IgG
145
ranking of tensile strength in implants
cobalt, titanium, stainless steel and cortical bone
146
effect of bisphos in Osteogenesis imperfecta
improves bone density, reduces fracture and reduces bone pain
147
COMP mutation leads to
pseudoachondroplasia and MED
148
COL2A1 mutation
SED - same as MED but with spine involvement
149
what is nitrogen containing bisphos
alendronate - works via farnesyl trasnfersase
150
Xlinked hypophosphatemic rickets vs hypophosphatasia
X-linked hypophos is a LOW phos and normal Ca due to bad kidney receptor - vit D resistent rickets; hypophosphatasia is s due to bad ALP; ca and phos are HIGH
151
what molecules are for compressive strength vs tensile
compressive - Ca-HA and proteoglycans and tensile is type 1 collagen
152
what gene contols axial skeleton development
HOX
153
level of evidence prospective cohort
level 2
154
what does lovenox do
enhances binding of AT3 to thrombin
155
what stimulates osteoblasts to differenitate
PTH and TGF b - for mesenchymal cells
156
definition of sensitivity
probability that positive Is a true positive IN THOSE WITH disease
157
which BMP invovled in FOP
BMP 4
158
what bmp is NOT osteoinductive
BMP 3
159
what nerves are obturator
L234
160
deep peroneal nn supplies which foot muscles
EHL, EDB
161
structure of osteons aka Haversions systems
osteons are defined by cement lines; inside are vascular canals that care artery, vein, neve; volkman are transverse connections; haversian CANALS are along the long axis
162
bone maturity woven vs lamellar
woven is immature; lammelar is more stiff and more organized
163
what makes mature osteoblasts
BMP; beta cantenin, PDGF, IDGF, TGF B;
164
how to bisphos prevent osteosclasts
inhibits ability to make microtubules at ruffled border leading to apoptosis
165
what cancer can you use bisphos to prevent skeletal events
multiple myeloma
166
collagen 1 composiition
1 alpha-2 chain; 2 alpha-1 chains - triple helxi
167
most abundant non collagen protein in bone
osteocalcin
168
ostenectin secreted by
platelets and osteoBlasts
169
bone vascularity high vs low pressure
nutrient artery is 2/3 of bone supply and is HIGH pressure; low pressure is periosteal supplies outer 1/3 via Volkman
170
how does estrogen help bone growth
inhibits adenylyl cyclase and decreases RANKL
171
which IL stimulate bone RESORPTION
IL 1 and 10 stimulate osteoclasts; IL 6 in myeloma
172
vitamin D requirements 1500
if pregnant, fracture healing; or post-menopause
173
vit D requirement 2000
lactating
174
vitamin D requirement 750
adults;
175
vitamin D requirement 1000-1350
yound adults and teens
176
vitamin D for kids
600-800
177
protrusio vs coxa prufunda
profunda is acetabulum is medial to iliosichial line; protrusio is femoral head is medial to ilioishcial line
178
gene transmission of duchenne
X-linked recessive
179
scleraxis does what
transcription factor for tendon/ligament
180
dexa scoring is Z or T
T score
181
indepdence lost at 1 year after hip fracture
50% at 1 year
182
what factor stimulates cartilage regeneration
TGF B
183
what happens to FGFR in achondroplasia
abnormally turned ON
184
what is pathologic cell in pagets and osteopetrosis
osteoclasts - but in pagets its INCREASED resorption; and in osteopetrosis its decreases osteoclasts
185
role of fibronectin
cell adhesion; growth, migration and development
186
fibrillin is associated with
elasin DEPOSITION
187
which metal has highest bacteria adherence
Ti-Alloy > Steel> pure titanium; tantalum Is relatively resistent
188
denosumab blocks and binds to
RANKL (LIGAND)
189
cells of nucleus pulposes as disc degenerates
decrease in size and cell
190
huntingtons repeat
CGG
191
inheritance of hemophilia
xlinked RECESSIVE
192
what factors BLOCK the osteolytic cascade
IL1 receptor antagonis; OPG, IFN gamma, IL 4 and IL 10
193
what factors mediate osteolysis
TNFa; IL6; IL 1; PG2; RANKL
194
what gait mechanic are a/w with KNEE oa progression
ADDUctor moment at tibia
195
what leads to cartilage brittleness with age
increaseing advanced end glyoclation products over time
196
heparin works by binding
Antithrombin 3
197
tensile strength of nerves comes from
collagen 1
198
what does transient osteoporosis of hip look like on MRI
BRIGHT on T2 bc more bone marrow edema; T1 is hypointense
199
tx of transient osteoP of hip
protected WB ; can last 6-8months -no surgery needed self limiting
200
ZPA zone of polarizing activity affect
hand polarization
201
order of nerve structure
ENDO; Perineural, fascile; EPI
202
sural nn runs with which vein
LESSER saphenous vein
203
what is purpose of funnel plot
to show publication bias in meta analysis - would want even funnel shape
204
what is best test to compare frequency or proportions
Chi-Squared test
205
sheathed tendons get their blood supply from
VINCULA - NOT paratenon
206
what restrains the swelling pressure from aggrecan
Collagen (2)
207
what is pathology of factor V leiden
leads to hypercoag due to increase thrombin activation
208
muscle fibers 1 vs 2
1 is slow; lower strength and speed; uses aerobic and oxidative energy; atrophies first; 2 is fast; fatigues quickly and is glycolytic
209
ach and muscle contraction
ACH binding leads to ca release - ca then binds tropoin - changes tropomyosin and leads to exposure of actin for myosin binding
210
what is tx for familial vit D resistent rickets
phosphate replacement and Vit D (calcitriol)
211
what are the vitamin D versions
D3; then 25D3 then 1,25 D3(Calcitriol)
212
tib ant activation during heel strike
eccentric followed by conccentric
213
microfracture stimulates what cells
mesenchymal cells from the marrow tomake fibrocartilage
214
what happens in factor v leidein
prevents inibition by activated factor C'
215
duchenne inheritance
xlinked RECESSIVE
216
how much force in medial knee if neutral
65% in neutral leg
217
what is epigenetics
gene alterations that do NOT involve DNA mutations
218
what is most common sx with PE
dyspnea - NOT tachycardia
219
renal osteodystrophy labs
hypoCa bc phosphate retained binds to Ca and damaged kidney cant make 1,25 Calcitriol; hyper PTH results
220
what other conditions are seen with renal osteodys
osteomalaciA, AVN, tendinitis and rupture; CTS due to amyloid; and brown tumors from hyperPTH
221
what is LOW turnover renal osteodystrophy
normal PTH; deposits of Alumininum in bone; impaired PTH release; disrupts mineralization
222
labs in vit D dependent type 1
low vit D 1,25 and low Ca,lowphos, high PTH and ALP
223
labs in vit D dependent type 2
HIGH vit D 1,25 and low Ca,lowphos, high PTH and ALP
224
labs in x linked vit D resistnet
LOW phos, normal Ca; low vit D 1,25 HIGH PTH and ALP
225
labs in hypophosphatasia
LOW ALP; high Ca, and hi phos; normal Vit D
226
Labs in renal osteodys
low Ca; high phos; high PTH; high ALP; low vit D
227
what happesn to proteoglycans in disk with aging
decreased - they get broken down
228
follow up time frame for lateral condyle growth arrest
3 years
229
LMWH is associated with increased
thrombocytopenia
230
muscle tension determinted by
cross section volume
231
what is effect of SCD
increased cardiac output; stroke volume; EF and MAP; pre load; reduce afterload
232
what cells fix muscle injuries
satellite cells
233
poland syndrome features
syndactyly with unaffected thumb; ipsilateral chest wall issues - absent pec; or assymetric nipples
234
max dose of abx in PMMA
up to 10gm of vanc and up to 12.5gm tobra for 40 gram PMMA
235
diff types of drug recall
class 1 is for serious harm or death; class 2 is temporary or reversible adverse events, class 3 is no adverse issues
236
which part of tendon covering provides neuro signal
ENDOtenon - closed layer to tendon; paratenon is most superficial
237
Strategies to minimize confounding
randomization, restricted enrollment, matching, and post hoc analyses.
238
force and excursion of muscle related to
muscle architecture - number and orientation of fibers
239
terres major innerveated by
lower subscap
240
how much can you lenghten leg before injuring sciatic
10% of femur or 4cm
241
transfemoral amputaiton increases how much E
60% increase
242
what Growth factor is for Chondrogenesis
TGF
243
forteo uses in osteoporosis fracture
can help if bisphos resistent
