General Flashcards
1
Q
most likely organisms to grown in CHRONIC (> 4wks) prosthetic joint infections?
A
- coagulase negative Staph
- Proprionibacterium acnes
2
Q
most likely organism to grown in ACUTE (
A
- Staph aureus
- beta hemolytic Strep
3
Q
joint aspiration results in a periprosthetic knee joint infection?
A
- WBC > 1,000
- >64% neutrophils
4
Q
T or F: a pt w/ BMI > 40 has a significantly increased risk of reinfection after a stage 2 revision has been completed?
A
True
5
Q
Avg blood loss for closed femur fx?
A
1250mL
6
Q
avg blood loss for closed tibia fx?
A
750mL
7
Q
In the presence of exsanguinating external hemorrhage, control of hemorrhage should take precedence over the ABCDE primary survey
A
.
8
Q
management of a tarsal navicular stress fx
A
NWB w/ cast immobilization as initial tx
9
Q
most common complication following locked plate and screw fixation of proximal humerus fx?
A
screw penetration of the articular surface (subsequently falls into varus deformity)
10
Q
management of irreparable rotator cuff tear (fatty infiltration) and glenohumeral arthritis?
A
conservative management (NSAIDs, corticosteroid injection, PT, and activity modification) -shoulder hemiarthroplasty and reverse total shoulder arthroplasty may be considered for pts who have failed a trial of non-op management
11
Q
Tx of LC-1 type pelvic injury
A
WBAT
12
Q
Nonossifying fibroma
A
- most commonly found in metaphysis of long bones, 80% in LE
- common locations include the knee (distal femur and proximal tibia) and distal tibia
- fibroblastic spindle cells in whirled or storiform pattern; fibroblastic connective tissue background; numerous lipophages and giant cells; hemosiderin pigmentation
13
Q
role of vertebroplasty in tx of vertebral compression fracture
A
No role; conservative management; progress to kyphoplasty if persistent pain
14
Q
management of post-axial polydactyly of the feet
A
no further work up necessary
15
Q
most abundant non-collagenous protein in bone?
A
osteocalcin
16
Q
osteocalcin
A
- most abundant non-collagenous protein in bone
- secreted by osteoBLASTS
- plays role in bone mineralization and calcium homeostasis
- biochemical marker for bone formation
- part of the ORGANIC matrix of bone
17
Q
bone matrix
A
- 40% organic
- 60% inorganic
18
Q
what is the organic matrix of bone made up of?
A
- collagen (90%, mostly type 1, TENSILE strength)
- proteoglycans (inhibit mineralization, COMPRESSIVE strength)
- matrix proteins (osteocalcin, osteonectin, osteopontin)
- cytokines and growth factors (IL-1, IL-6, IGF, TGF-b, BMP)
19
Q
what makes up the inorganic components of bone?
A
- calcium hydroxyapatitie
- osteocalcium phosphate (brushite)
20
Q
major source of nutrition to the growth plate
A
Perichondral artery of La Croix
21
Q
cortical capillaries drain where?
A
emissary venous plexus
22
Q
high pressure system that branches from major systemic arteries and supplies the inner 2/3 or mature bone?
A
Nutrient arteries
23
Q
Blood supply to long bones
A
- nutrient artery system (high pressure)
- epiphyseal-metaphyseal system
- periosteal system (low pressure)
24
Q
during early fracture healing, blood flow is which way?
A
centripetal (outside to inside; because high pressure nutrient artery system is often disrupted)
25
which artery system provides blood to the outer 1/3 of diaphyseal long bones?
periosteal arterioles
26
main difference between lamellar and woven bone
woven bone is disorganized and NOT oriented by stress patterns. lamellar bone is organized by stress patterns
27
tx for muscle injuries, including partial lacerations
-affected extremity should be immobilized no more than 3-5 days, followed by a progressive strengthening and stretching program
28
what is the proper placement of ACL reconstruction femoral tunnel?
- 10:30 in a R knee, 1:30 in a L knee
- these positions attempt to reconstruct both the anteromedial bundle, which provides AP stability, and the posterolateral bundle, which provides rotational stability
- improper femoral graft placement is one of the most common reasons for ACL revision surgery
29
positive ER dial test at 30 degrees indicates what?
Posterolateral corner injury
30
"burner" or "stinger"
- transient unilateral neurapraxia
- most commonly involves the biceps, deltoid, and rotator cuff muscles
- return to play requires normal strength and sensation in both upper extremities as well as a normal cervical spine exam (including ROM, compression, Spurling's Adson's, and resistive head pressures)
31
differential diagnosis of lower leg pain from exercise
- chronic exertional compartment syndrome
- medial tibia stress syndrome
- fibular and tibial stress fractures
- fascial defects
- nerve entrapment syndrome
- vascular claudication (atherosclerotic or popliteal artery entrapment syndrome)
- lumbar disc herniation
32
popliteal artery entrapment syndrome
- presents w/ intermittent claudication and decreased pulses
- compression of popliteal artery by the medial head of gastrocnemius
- passive dorsiflexion and plantarflexion provokes symptoms
- arteriogram demonstrates compression
- sx often relieved w/ exercising for a few minutes
33
functions of the ACL
Primary restraint to anterior translation of the tibia relative to the femur.
Secondary restraint to tibial rotation and varus/valgus rotation.
34
typical findings in ACL deficient knees
anterior shift and internal rotation of the tibia at low flexion angles.
medial translation of the tibia between 15-90 deg of flexion.
35
MCL deficiency
increased valgus rotation and slightly increased internal rotation
36
PLC deficiency
increased external rotation of tibia
37
is weight training and plyometrics safe for adolescents?
yes, it can generate gains in strenght secondary to improved neuromuscular activation and coordination, rather than hypertrophy
38
when is open hamstring tendon repair recommended in athletes?
- when all of the hamstring tendons have avulsed off their origin or 2 tendons have avulsed and retracted more than 2 cm
- remember to test the peroneal branch of the sciatic nerve function, as injury to this branch will cause weakness of the short head of the biceps femoris and may slow potential post-op rehab
39
tx of single tendon hamstring rupture/avulsion?
- non op tx
- rest, ice, weight bearing as tolerated, NSAIDs, gentle stretching, therapeutic exercise, and gradual return to athletic activity over approx. 4-6 wks
40
name the 3 hamstring muscles
- biceps femoris
- semimembranosis
- semitendinosis
41
radiographic findings of a lateral (typical) discoid meniscus
-widening of the lateral joint space, squaring of the lateral condyle, cupping of lateral tibial plateau and hypoplasia of the lateral tibial spine
42
discoid meniscus
- occur in 3-5% of population
- usually lateral, and may be bilateral in 25-50%
- sagittal MRI showing meniscal continuity in three 5mm sagittal images ("bow-tie sign") is diagnostic
- if pain, mechanical sx, meniscal tear or detachment, arthroscopic debridement and saucerization is indicated
- no difference in saucerization w/ or w/o stabilization
43
MR findings w/ chondromalacia patellae
-high cartilage signal on T2 or proton density weighted MR images
44
findings consistent w/ bucket handle tear (usually medial) of meniscus
- double anterior horn sign
- double PCL sign (second smaller PCL lying anteroinferior to the native PCL)
- flipped meniscus sign and disproportional posterior horn sign
45
cystic lesion within the meniscus demonstrating high signal intensity on T2 weighted imaging
meniscal cyst
46
what is the most common long-term complication after meniscal transplantation?
meniscal graft tear
| -graft failure that results from graft tears is thought to be related to the acellularity of graft tissue
47
what is the return-to-play progression protocol for sports concussion?
1. no activity (complete physical and cognitive rest)
2. light aerobic activity (walking, swimming, stationary cycling at 70% max HR; no resistive exercises)
3. sports-specific exercises (specific sports-related drills but no head impact)
4. noncontact training drills (more complex drills, may start light resistance training)
5. full contact practice (after medical clearance, participate in normal training)
6. return to play (normal game play)
Athletes must be symptom-free through each step, which is usually monitored for at least 24hrs
48
most common cause of early failure following ACL reconstruction?
malpositioned tunnel
49
what is the ideal tunnel placement for ACL reconstruction?
femoral side: approx 2 o'clock (for a L knee) or 10 o'clock (for R knee) position on the lateral wall, which facilitates a more horizontal, anatomic graft
tibial side: trajectory in the coronal plane should be about 60-75 deg from the horizontal and the tunnel entrance should be approx. 10-11mm from the anterior border of the PCL
50
ways to treat articular cartilage defects
- debridement
- fixation of unstable osteochondral fragments
- marrow stimulation techniques (microfracture, abrasion chondroplasty)
- cartilage replacement techniques (osteochondral autograft and allograft)
- cellular techniques (autologous chondrocyte implantation)
51
mechanism of carb loading?
maximizes stored MUSCLE glycogen for endurance after 90 min of exercises
52
typical carb depletion/loading regimen?
a hard workout followed by 3 days of a low carb diet, another hard workout, and another 3 days of a high carb diet
53
which class of meds has been shown to improve skeletal muscle regeneration and decrease fibrosis following muscle injury in an animal model?
angiotensin II receptor blockade (e.g. losartan)
54
after successful ACL reconstruction, which of the following factors has shown to contribute the greatest influence on a player's decision to return to sport?
lifestyle and psychological factors
- return to preinjury level of sport is frequently expected within 1 yr after ACL reconstruction
- factors associated w/ not returning to preinjury level sport: previous ACL reconstruction to either knee, poorer hop-test symmetry and subjective knee function
- fear of reinjury is considered one of the most common reasons cited for a post-op reduction in or cessation of sports participation
55
when should an athlete return to play if they have infectious mononucleosis?
3 wks AFTER symptom resolution
- LIGHT activity after 3 wks from symptom onset when afebrile, has a good energy level, and does not have any significant associated abnormalities
- CONTACT sports after at least 3 wks when athlete has no remaining symptoms, is afebrile, and has a normal energy level
56
absolute contraindications to meniscal transplantation?
- inflammatory arthritis
- diffuse arthritis
- outerbridge grade IV changes
- untreated tibiofemoral subluxation
- synovial disease
- previous joint infection
- skeletal immaturity
- marked obesity
57
indications for meniscal transplantation
- after non-op measures have failed (unloading braces, weight loss, activity modification, analgesia)
- young pts (
58
discoid meniscus
- imaging shows squaring of affected condyle (lateral > medial), w/ cupping of tibial plateau
- abnormal development of a hypertrophic and discoid shaped meniscus
- 3-5% of population
- considered the most common cause of a symptomatic clicking or clunking in a childs knee
- lateral meniscus most commonly involved, and will occur b/l in 25% of affected people
- the WATANABE classification describes 3 types: type 1 = incomplete, type 2 = complete, type 3 = Wrisberg (lack of posterior meniscotibial attachment to tibia)
- majority of discoid tears occur in the posterior or middle aspect of the discoid meniscus
- partial meniscectomy yielded better radiologic results than subtotal/total meniscectomy for torn discoid menisci in pediatric population
59
diagnosis of discoid meniscus
3 or more 5mm sagittal images on MRI (bow-tie sign)
60
which meniscus is bigger?
Medial (medial has more)
61
Watanabe classification
discoid meniscus
1. incomplete
2. complete
3. Wrisberg (missing posterior coronary ligament)
4. Ring shaped
62
internal snapping hip (coxa saltans)
- caused by psoas tendon sliding over femoral head, iliopectineal ridge, lesser trochanter exostoses, or iliopsoas bursa
- hip pain and popping w/ activity
- PE findings of moving from hip flexion-abduction-external rotation to neutral triggers a popping sensation
63
snapping hip syndrome
- 3 forms: 1, external snapping hip, which is caused by the IT band sliding over the greater trochanter; 2, internal snapping hip; 3, intraarticular snapping hip, which is caused by loose bodies or labral tears
- tx: if painful, activity modification, PT, steroid injections; surgical tx (ITB z-plasty or psoas tenotomy) is indicated if non-op management is unsuccessful
64
PE findings w/ pincer-type femoroacetabular impingement
- pain w/ internal and external rotation of hip w/ hip and knee in extended position
- internal rotation only to neutral w/ hip flexed to 90 deg, but full external rotation
65
PE findings of cam-type femoroacetabular impingement
-decreased internal rotation and a positive impingement test (forced flexion, adduction, and internal rotation)
66
signs of athletic pubalgia
pain w/ half sit-up and tenderness at the pubic ramus
67
what is associated with a mal-positioned vertical femoral tunnel in ACL reconstruction?
-persistently positive pivot shift and lower Lysholm satisfaction scores
68
bundles of the ACL
- 2 bundles: anteromedial and posterolateral
- AM is longer and tight in FLEXION (you flex in the AM)
- PL is shorter and LOOSE in flexion
- AM bundle is attached anterior to the PL bundle on the TIBIA
- on the femur, the AM bundle begins at the proximal-anterior aspect of the femoral insertion site, while the PL bundle begins at the posterior-inferior part
- in extension, the AM bundle is LOOSE and the PL bundle is TIGHT
69
best reason to use an autograft (rather than an allograft) for ACL reconstruction in a young athlete?
lower graft rupture rate
70
what is the primary function of the posterior oblique ligament in the knee?
resist internal tibial rotation w/ the knee in full extension
71
function of superficial MCL
resists valgus and external rotation forces
72
role of osteoprotegerin (OPG)?
binds to and sequesters RANK-L
| -causes decreased production of osteoclasts by inhibiting the differentiation of osteoclast precursors
73
molecules shown to inhibit osteoclasts
- OPG (binds RANK-L)
- calcitonin (binds osteoclasts)
- estrogen (decreases production of RANK-L)
- TGF-b (increases OPG)
- IL-10 (suppresses osteoclasts)
74
calcitonin mechanism
decreases osteoclast activity by directly binding to receptor on osteoclast
-decreases osteoclast number and activity, as well as decreases serum calcium
75
molecules known to activate osteoclasts
- RANK-L (binds to RANK)
- PTH (binds to osteoblasts to stimulate production of RANK-L and M-CSF, activates adenylyl cyclase)
- IL-1 (stimulates osteoclast differentiation)
- 1,25-dihydroxy vitamin D (stimulates RANK-L)
- PGE-2 (activates adenylyl cyclase)
- IL-6 (myeloma)
- MIP-1A (myeloma)
76
influence of PTH and 1,25-dyihydroxyvitamin D on osteoblasts?
-cause secretion of RANK-L
77
do bisphosphonates act on osteoblasts or osteoclasts?
-osteoclasts
78
PTH receptor activation primarily acts through which pathway?
-adenylyl cyclase/G-alpha stimulatory protein/cAMP/ protein kinase A in OSTEOCYTES
79
the binding of RANK-L to RANK on causes what?
- RANK-L binds to RANK on osteoclast precursor cells, causing differentiation into mature osteoclasts (multinucleated giant cells)
- mature osteoclasts then bind to bone surfaces via integrins and resorb bone in Howship's lacunae
80
role of sclerostin?
-glycoprotein secreted primarily by osteocytes that act as negative regulator of bone mass through inhibition of bone formation by osteoblasts
81
what do osteoclasts secrete?
fibroblast growth factor-23 (FGF-23), BMPs and sclerostin to regulate osteoblast activity
82
who do bisphosphonates work?
both classes function to induce OSTEOCLAST apoptosis
83
Denosumab
monoclonal antibody to RANK-L, which binds to and prevents it from stimulating RANK
84
PTH mechanism
stimulates osteoblast to secrete RANK-L, when then goes on to stimulate the osteoclast precursor to become active
85
Calcitonin
- hormone secreted by the parafollicular cells of the thyroid gland to slow bone resorption, reduce calcium resorption in the tubules of the kidney, and reduce serum calcium
- opposes the effects of PTH
- secretion is upregulated by hypercalcemia, gastrin, and pentagastrin
86
peak bone mass attainment in both men and women is most dependent on which sex-steroid?
-estrogen
87
risk factors for osteoporosis?
- increasing age
- female sex
- early menopause
- fair-skinned
- family hx of hip fx
- low body weight
- smoking
- glucocorticoid use
- excessive alcohol
- low protein intake
- anticonvulsant or antidepressant use
88
what disease process occurs due to over-secretion of a hormone that preferentially affects the proliferative zone of the growth plate?
gigantism (over secretion of growth hormone)
89
how does longitudinal bone growth occur?
at the growth plate by endochondral ossification in which cartilage is first formed and then remodeled into bone tissue
90
layers of the growth plate?
- the resting zone
- the proliferative zone
- the hypertrophic zone
91
disproportionate dwarfism, spinal involvement, and a barrel chest from a COL2A1 mutation
Spondyloepiphyseal dysplasia (SED)
92
"hitch-hikers" thumb, cauliflower ear, cleft palate, and short-limbed dwarfism
Diastrophic dysplasia
| -due to a sulfate transport mutation
93
defect in core-binding factor alpha 1 (CBFA-1) causing dwarfism and absent clavicles
cleidocranial dysplasia
94
disproportionate dwarfism w/ multiple epiphyses involved, shortened metacarpals, valgus knees, but no spinal involvement
- Multiple epiphyseal dysplasia (MED)
| - due to a COMP mutation
95
during what age do most people achieve their peak bone mass?
16-25 yrs
96
what portion of the biceps tendon distal insertion is typically injured in partial biceps tears?
The Radial side of the footprint of the insertion
97
main flexor of the arm?
Brachialis
98
main supinator of the arm
biceps brachii
99
what nerve is injured most commonly during the superficial dissection when repairing a distal biceps rupture through a single incision anterior approach?
Lateral antebrachial cutaneous nerve
100
bone resection in TKA?
6 deg valgus distal femoral cut, neutral tibial cut
101
TKA: what should you do if tight in both flexion and extension?
symmetrical gap
| -cut more proximal tibia
102
TKA: what to do if extension gap is good, but you're loose in flexion?
asymmetric gap, too much posterior femur was cut
- upsize femoral component
- fill posterior gap w/ cement or metal augment
103
TKA: what do you do if extension gap is tight and flexion gap is good?
asymmetric gap, either not enough of posterior capsule was released or not enough distal femur was cut
- release posterior capsule
- cut more distal femur in 1-2mm increments
104
TKA: what do you do if extension gap is good, but flexion gap is tight?
asymmetric gap, tibial bone cut has no posterior slope and either not enough posterior bone was cut or if a PCL retained implant is used, PCL is too tight and scarred down
- size of femoral component should be downsized
- PCL should be recessed
- posterior slope of tibia should be reassessed and recut if slope is anterior
105
TKA: what do you do if extension gap is loose and flexion gap is good?
asymmetric gap, either too much of distal femur was cut or A-P size of implant is too big
- distal femoral augmentation should be performed
- smaller size (A-P) femoral component should be used
- thicker tibial poly insert
106
what is the normal anatomic axis of the lower limb?
6 degrees of valgus from the mechanical axis of the lower limb, and 9 degrees of valgus from the true vertical axis of the body
107
what is the anatomical axis of the tibia?
3 degrees of varus from the true vertical axis of the body
108
how is the proximal tibial cut made?
perpendicular to the MECHANICAL axis of the tibia (anatomic axis is 3 deg of varus)
109
how should the femoral component be placed in TKA?
- 3 deg of ER relative to the posterior condylar axis(to compensate for neutral tibial cut, which is normally in 3 deg varus), place lateral instead of medial if you have to choose for patellar tracking purposes
- or neutral to epicondylar axis
- or perpendicular to AP axis
110
where should the patellar component be placed in TKA?
Medial and superior for best tracking (think of a patella w/ MS)
111
when can you NOT use the posterior condylar axis to determine axial rotation of femoral component?
- when you have a hypoplastic lateral femoral condyle or significant posterior condylar wear
- Instead you can place parallel to epicondylar axis or perpendicular to AP axis
112
two techniques to align the tibial component rotationally?
- place center of tibial tray over the junction of medial third of the tibial tubercle w/ lateral 2/3 of tibial tubercle
- place trial components and range the knee, allowing tibial to align w/ flexion axis of the femur
113
Q angle
-angle between the line extended from anatomical axis of femur, and the line between the center of the patella and tibial tubercle
114
3 primary factors affecting patellofemoral tracking in TKAs?
- femoral component rotation
- maintenance of joint height
- reproduction of pre-op patellar thickness
115
Remember that the normal tibia internally rotates (femur ER) during flexion w/ greater posterior translation of the lateral femoral contact point on the tibia relative to the medial femoral contact point. The net effect of this internal rotation during flexion is to center the tibial tubercle in flexion or diminish the Q angle
.
116
is there a difference between anterior approach to hip vs lateral or posterior?
- anterior: greater blood loss and operative times during the learning curve period (60-100); higher risk of femoral component failure d/t difficult exposure of femur
- posterior: lower risk of needing early revision compared to anterior or lateral; higher risk of acetabular component loosening compared to lateral or anterior; greater risk of instability
117
DNA
double stranded deoxyribose
118
exon
-portion of a gene that codes for mRNA
119
mRNA
-translates and transfers DNA info into protein synthesis machinery
120
tRNA
-transfers amino acid to mRNA
121
Transcription
DNA-->mRNA
122
translation
mRNA-->protein
123
Achondroplasia gene defect
FGF receptor 3
124
Signal transduction
-process of converting extra-cellular signals to cell response
125
RANKL
a key molecule in osteoclastogenesis
| -inflammatory stimuli may stimulate OSTEOBLASTS to express RANKL
126
Recombinant technology
-manipulation of DNA or RNA segments to produce specific desired DNA, RNA, or amino acids
127
Infliximab
- monoclonal antibody for TNF-a
| - prevents TNF-a from binding its receptors
128
Etanercept
- competitive inhibitor of TNF-a signaling
| - its a fusion protein that combines the ligand binding domain of the TNF-a receptor
129
key molecules that can control excessive osteoclastogenesis
- OPG
- anti-TNFs
- anti-RANKLs
130
Mechanical equilibrium
when the sums of all forces and moments are zero
131
free body diagrams
show the locations and directions of all forces and moments acting on a body
132
Kinematics
-describes the motion of objects without regard to how that motion is brought about
133
Kinetics
-involves analysis of the effects of forces and/or moments that are responsible for motion
134
Each joint has specific load interactions because of the particular characteristics of the joint and the muscle actions that cross the joint
.
135
Stress
-force per unit area
136
Strain energy
- the amount of energy stored in a loaded material
| - in a stress-strain curve, it represents the area under the curve
137
Modulus of elasticity
- the ratio of stress to strain
- measures the ability of a material to maintain its shape under the application of external load
- the HIGHER the modulus of elasticity, the STIFFER the material
138
Polar moment of inertia
- the quantity that is determined by the cross-sectional area and distribution of tissue around a neutral axis in torsional loading
- the LARGER the polar moment of inertia, the STIFFER and STRONGER the material
139
viscoelastic material
-has properties that are rate dependent or have time dependent responses to applied forces
140
isotropic material
- has the same mechanical properties in all directions
| - in general, ceramics and metals are isotropic
141
anisotropic material
- has properties that differ depending on the direction of load
- bone, muscle, ligament, and tendon all are anisotropic
142
alloys
-metals composed of mixtures or solutions of metallic and nonmetallic elements that are varied to influence their biomechanical properties, including strength, stiffness, corrosion resistance, and ductility
143
properties of a polymer
-dictated by its chemical structure (the monomer), the molecular weight (the number of monomers), the physical structure (the way monomers are attached to each other), isomerism (the different orientation of atoms in some polymers), and crystallinity (the packing of polymer chains into ordered atomic arrays)
144
ceramics
-solid, inorganic compounds consisting of metallic and non-metallic elements held together by ionic or covalent bonds
145
Formation of the bony skeleton
-occurs via either intramembranous bone formation or endochondral bone formation
146
intramembranous bone formation
-occurs through osteoblast activity
147
endochondral ossification
-occurs at growth plates and within fracture callus
148
In the primary center of ossification
- blood-borne precursors of osteoblasts and osteoclasts are delivered by the capillaries
- this process signals the transition from the embryonic to the fetal period and occurs first at the humerus
149
the total length of the growth plate depends on what?
-the number of cell divisions of the progenitor cell
150
the region of the hypertrophic zone where mineralization occurs
-known as the zone of provisional calcification
151
SCFE involves what zone?
-the hypertrophic zone
152
The genetic mutation in achondroplasia
-defect in FGFR-3
153
Growth plate injuries and the Hueter-Volkmann law
- occur when the mechanical demands of bone exceed the strength of the epiphysis-growth plate metaphysis complex
- the Hueter-Volkmann law states that increasing compression across the growth plate leads to decreased growth
154
Diastrophic dysplasia
-defect in proteoglycan sulfation
155
Bacterial infection affects what portion of the growth plate?
the metaphyseal portion
156
Scurvy
-caused by a vitamin C deficiency w/ resultant decrease in chondroitin sulfate and collagen synthesis
157
Endochondral bone formation
- occurs in long and short bones
| - occurs through a cartilage model
158
intramembranous bone formation
- occurs in flat bones
| - results from condensations of mesenchymal tissue
159
The inner 2/3 of cortical bone is vascularized by what?
-nutrient arteries that pass through the diaphyseal cortex and enter the intramedullary canal and are at risk during intramedullary reaming
160
The outer 1/3 of cortical bone derives blood supply from what?
- the periosteal membrane vessels
| - these vessels are at risk w/ periosteal stripping during surgical procedures
161
The extracellular matrix of bone is composed of what?
- 60-70% mineral components and 20-25% organic components
| - the organic matrix is 90% type 1 collagen and 5% noncollagenous proteins
162
Type 1 collagen
- fibril forming and has a triple helical structure (three alpha chains)
- the fibrils are intrinsically stable because of noncovalent interconnections and covalent cross-links between lysine residues
163
Mature osteoblast marker proteins
-include alkaline phosphatase, osteocalcin, osteonectin, and osteopontin
164
what are the potential fates of a mature osteoblast?
-differentiation into an osteocyte or bone lining cell, or apoptosis
165
The marker proteins for osteoclasts
-TRAP, calcitonin receptor, and cathepsin-K
166
Osteoclast differentation and activity are regulated by what?
-in large part by the bioactive factors RANKL (positive regulator) and OPG (negative regulator)
167
Osteoblast and osteoclast functions are coupled via various systemic and local factors. Regulatory proteins (RANKL and OPG) secreted by osteoblasts provide direct coupling in bone remodeling
.
168
Fractures commonly heal w/ what mechanism?
- a combination of endochondral and intramembranous bone formation
- motion at the fracture site results in healing primarily through endochondral ossification, whereas stability at the fracture site enables direct intramembranous ossification
169
Fracture healing stages
-sequence of biologic stages including: injury, inflammation, hematoma formation, hypertrophic cartilage formation, new bone formation, and remodeling to mature bone
170
Articular joint synovium is composed of what two layers?
-the intimal lining, which contains tissue macrophage-like cells and fibroblast-like cells that produce hyaluronin, and the connective tissue sublining
171
Giant cell tumor
- epiphysis of long bones
- female predominance
- usually occur around knee and sacrum
- neoplasticism mononuclear storm all cell, characteristic multinucleated giant cells
172
Osteofibrous Dysplasia
- cortically based lytic lesion
- expansile
- loose stroma of fibroblas-like spindle cells
173
Adamantinoma
- looks-like OCD
| - epithelial clusters in mesenchymal background
174
Nonossifying Fibroma (NOF)
- eccentric
- cortically based lytic lesion
- multiloculated
- sclerotic border
- often found incidentally
- similar to FD
- spindle shaped fibroblasts w/ woven bone, WITH rimming osteoblasts
175
Fibrous Dysplasia
- sporadic disorder
- mutation of Gs-alpha gene (activates adenylate cyclase, increased cAMP)
- GROUD GLASS APPEARANCE
- metaphyseal or diaphyseal
- proximal femur, well-defined
- proliferative fibroblasts
- irregular trabecaulae (alphabet soup)
- NO rimming osteoblasts
176
Diaphyseal Tumor Location
-AEIOUY
-Adamantanoma
-Eosinophilic granuloma
-Infection
.....
177
Unicameral Bone Cyst (UBC)
- thin fibrous lining
- fibrous tissue
- giant cells
- hemosiderin
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Aneurysmal Bone Cyst (ABC)
- Eccentric
- Metaphyseal
- Expansile
- fluid-fluid levels on MRI
- cystic wall: spindle-shaped fibroblasts
- giant cells
- blood-filled lakes
- must rule out telangiactatic osteosarcoma
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Melorrheostosis
-Flowing candle wax disease
180
Carcinoma
-nests of cells forming glands
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Tumors that metastasize to lymph nodes
-ESARC
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segond fracture (pathognomonic for ACL rupture) is due to avulsion of what structure?
Anterolateral ligament of knee (lateral capsular ligament)
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isthmic spondylolisthesis consistently correlates w/ what pelvic parameter?
Pelvic incidence
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neurovascular structures at risk during fasciotomies of the lower leg?
The structures at risk are the anterior tibial artery and deep peroneal nerve in the anterior compartment, superficial peroneal nerve in the lateral compartment, sural nerve in the superficial posterior compartment, and posterior tibial nerve and posterior tibial and peroneal arteries and veins in the deep posterior compartment.
185
end stage ankle arthritis is most commonly attributable to what?
Trauma
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best position of glenoid component in rTSA to prevent notching?
place baseplate as inferiorly as possible on glenoid w/ an inferior tilt
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evaluation of pts w/ bunion (hallux valgus)
Important clinical findings for presurgical planning include pes planus, the amount of great toepronation, first ray instability, metatarsal head tenderness, and lesser-toe alignment. The radiographic features that are important include the hallux valgus angle, first/second metatarsal intermetatarsal angle, degenerative changes in the first MTP joint, congruency of the hallux MP joint, and sesamoid position. This patient has a moderate first/second intermetatarsal angle, pronation of the great toe, and moderatesesamoidsubluxation without significant degenerative changes of the first MTP joint. These features are indications for a proximal metatarsal osteotomy with a distal soft-tissue release. A distal Chevron osteotomy is used to address milder deformities without substantial sesamoid subluxation or metatarsus primus varus. In isolation, an Akin osteotomy is used for hallux valgus interphalangeus. Arthrodesis of the first MTP joint may be appropriate for treatment of specific severe deformities or for major degenerative changes. Keller resection arthroplasty for hallux valgus treatment is generally reserved for low-demand elderly patients.
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restrictions after tibial tubercle osteotomy to improve exposure during a TKA?
None
189
Which gene mutation or polymorphism has been shown to most increase the risk for venous thromboembolic disease after elective total joint arthroplasty?
MTHFR/C677T/TT
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surgical approach to talar neck fractures?
Typically through both medial and lateral incisions to prevent varus malreduction from medial comminution thru just a lateral incision
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Does the fibula need to be fixed in complex pilon fractures?
No, increased postsurgical complication rates have been reported
192
Which artery provides the dominant blood supply to the humeral head?
Posterior humeral circumflex artery
193
should you plate the fibula when treating distal tibial metaphaseal fx's (with IMN) in association w/ fibula fx's?
Yes
194
what types of implants should be used in pts w/ OI who sustain fractures
Load SHARING
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The recommended DVT treatment duration is dependent on clot location, causative factors, and patient history. If there is a reversible risk factor (ie, surgery) and no prior history of blood clots, a 3-month duration of anticoagulation is typically recommended. Lifetime anticoagulation is recommended when a patient has a second blood clot, malignancy, or an unprovoked proximal blood clot or pulmonary embolism. The role of serial ultrasounds and serial measurements of D-dimer to determine the duration of anticoagulation has not been established. Blood clots in peripheral distal veins are treated with 6 to 12 weeks of anticoagulation therapy
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196
what condition is most commonly associated w/ anterolateral tibial bowing?
NF-1
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Which radiographic abnormality most accurately serves as a predictor of ankle syndesmosis disruption?
tibiofibular clear space exceeding 6 mm on both the AP and mortise views was the most reliable predictor of early syndesmotic widening.
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Larsen syndrome
bilateral dislocated knees, which is a hallmark of Larsen syndrome. Larsen syndrome is a mutation in the gene that encodes for filamin B, a protein that is important to cellular cytoskeleton structure, especially among chondrocytes. Patients with Larsen syndrome can have significant instability of the cervical spine, which, if left untreated, can lead to myelopathy or paralysis. Proceeding with any surgery to address the lower extremity without first imaging the cervical spine can lead to iatrogenic spinal cord injury from endotracheal tube placement.
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Relative to the null hypothesis, a type II error...
Incorrectly accepts a false null hypothesis
200
mutations for NF?
GNAS1
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PIP stability is dependent upon which percentage of intact middle phalanx articular surface?
60%
-Fractures of the volar base of the middle phalanx are very common injuries. After a congruent reduction, stability of the PIP joint is the most important treatment consideration. If the joint is stable, simple immobilization for comfort followed by early protected motion is adequate treatment. Clinical and cadaveric studies have demonstrated that injuries involving 20% of the volar articular surface of the middle phalanx are uniformly stable, whereas compromise of 60% of the articular surface leads to uniform instability. The threshold at which dorsal subluxation becomes problematic appears to be fractures involving 40% or more of the articular surface. Injuries of this pattern need to be examined carefully for evidence of instability and treated accordingly.
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Lachman test grading
Grade 0: negative
Grade 1+: 0-5mm anterior translation
Grade 2+: 5-10mm anterior translation w/ no endpoint
Grade 3+: >10mm anterior translation w/ no endpoint
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PIN injury findings after annular ligament reconstruction/repair
The posterior interosseous nerve (PIN) is very close to the annular ligament at the radial head. The PIN can be injured during surgical procedures in this area, particularly during annular ligament repair or reconstruction. The PIN is the deep motor branch of the radial nerve and does not have a sensory distribution. It supplies the extrinsic wrist extensors with the exception of the extensor carpi radialis longus. A PIN palsy usually causes the inability to extend the thumb and other digits at the MCP joints. The intrinsic extensors can still function in an isolated PIN palsy because they are supplied by the ulnar nerve. A radial nerve palsy also would involve weakness of wrist extension and loss of sensation in the dorsal forearm, but an isolated PIN palsy is more common after annular ligament reconstruction or repair because the PIN branch lies closer to the surgical field.
204
What is the most common type of neonatal brachial plexus palsy?
upper trunk injury
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Surveillance for growth arrest resulting from pediatric lateral condyle fracture should continue for how long after injury?
3 years
- Lateral condyle fractures in skeletally immature patients are uncommon. There fxs are notoriously difficult to reduce, even w/ an open approach.
- The blood supply to the lateral condyle fragment enters posterolaterally. Disruption of the blood supply may lead to osteonecrosis of the capitellum, so great care should be taken during open approaches to the elbow in skeletally immature patients, especially during lateral condyle open reduction and internal fixation.
Treatment of lateral condyle fractures in skeletally immature patients may be fraught with danger. The most common complication is persistent stiffness.
Growth arrest is a surprisingly rare complication, considering the fracture usually involves the capitellar physis, and reduction of the physis is often radiographically imperfect even with open reduction. However, this may be an underrecognized complication because arrest of the capitellar physis may not be evident until 1 to 3 years postinjury—beyond the time at which some surgeons or patients believe follow-up is necessary. Growth arrest has been reported with smooth wire fixation and lag screw fixation. The average time to radiographic union of a lateral condyle fracture is 6 weeks.
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Morton's neuroma
Morton’s neuromas are a common cause of forefoot pain. They are caused by an entrapment neuropathy of the digital nerve in the web space. Histologically, perineaural and endoneural fibrosis are both present. Surgically, the IMT ligament is most commonly released and the neuroma is resected. This can be done through a dorsal or plantar approach. The plantar approach is typically reserved for revision cases but can be used in primary cases as well. Studies show that isolated release of the IMT ligament is not appropriate because of the high rate of continued postoperative pain, thought to be the result of irreversible changes that have already occurred in the nerve.
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Poland syndrome and Sprengel deformity cause?
Poland syndrome and Sprengel deformity are hypothesized to occur as the result of interruption of the embryonic subclavian blood supply. Poland syndrome occurs proximal to the internal thoracic artery and distal to the vertebrals artery; Sprengel deformity is thought to occur via interruption of the subclavian, internal thoracic, or suprascapular artery.
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Hair tourniquet syndrome
occurs most often in children younger than 2 years of age. Human hair, which is often not seen in the band, circumferentially strangulates a digit or extremity. If not recognized and treated promptly, auto-amputation distal to the hair tourniquet may occur.
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Fibular hemimelia
Nearly all of these patients have an absent Anterior Cruciate Ligament. Additional associations include, absent rays of the foot, tarsal coalition, hypoplastic or aplastic fibula, leg-length discrepancy, femoral and tibial hypoplasia and lower extremity angular deformity.
210
MYH3 mutations
Freeman-Sheldon syndrome, Sheldon-Hall Syndrome and Distal arthrogryposis have been associated with mutations of MYH3, the gene which codes for myosin heavy chain 3.
211
NF1 associations
Fifty percent of patients with Neurofibromatosis type 1(NF1) (Figures 8 and 9) will have musculoskeletal manifestation of the disease; most commonly scoliosis and pseudarthrosis of the tibia. Twenty percent of patients with NF1 present with scoliosis. Dystrophic scoliosis is typical of NF1. Dystrophic features of include: scalloped vertebra, penciled ribs, severe rotation, sharp and short (4-6 vertebrae) kyphoscoliosis. Although NF1 has autosomal dominant inheritance, 50% of new cases are due to sporadic mutation. The NF1 gene on chromosome 17 codes for neurofibromin, a tumor suppressor.
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Beckwith-Wiedemann syndrome
associated with chromosome 11 mutations near the IGF gene
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most common site for rotator cuff tears?
Fundamental to understanding the pathogenesis of rotator cuff tears is an appreciation of the likely initiating site of the disease process. Although authors initially postulated that rotator cuff tears originated in the anterior margin of the supraspinatus tendon near the biceps tendon, recent research has challenged this notion. Kim and associates analyzed 360 full-thickness or partial-thickness rotator cuff tears using ultrasonograms. They separated stratified tears based on their anteroposterior size and whether they were partial- or full-thickness tears. The mean width and length of tear size was 16.3 mm and 17 mm, respectively. Histograms showed that the most common tear location for all tears regardless of size was approximately 15 mm posterior to the biceps tendon. This corresponds to the center of the rotator crescent initially described by Burkhart and associates. This location is described as being more susceptible to degeneration secondary to its diminished vascular supply and mechanical properties. The rotator cable is an arch-shaped thick bundle of fibers that is thought to shield the crescent from stress.
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What does an unpaired student t-test require?
normally distributed data
215
Tibial tubercle osteotomy for patellofemoral instability
TTO is a common treatment for patellofemoral instability. The angle of correction must be customized to each patient’s anatomy. For this patient, the orthopaedic surgeon plans an osteotomy that will both anteriorize and medialize the tubercle. This will consistently result in a change of patellofemoral kinematics and contact pressures. Medialization decreases lateral and increases medial patellofemoral contact pressures, and anteriorization shifts contact pressures from distal to proximal. Significant anteriorization may not be desired in a patient with proximal patellar chondrosis unless a concomitant chondral procedure is performed as well. The patellar height (Caton-Deschamps ratio) is normal, precluding the need for distalization but not medialization. The TT-TG distance, at more than 20 mm, is a strong indication for osteotomy. The Q angle, although a less precise indicator of malalignment, is also elevated and would be considered an indication for osteotomy.
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Distal femoral valgus osteotomy in young pts
Distal femoral varus osteotomy (DFVO) is intended forpatients younger than age 50,more active patients with isolated lateral compartment arthritis and valgus malalignment. Although the knee functional score improves at 1-year follow-up, the function scores significantly deteriorate at 10-year follow-up. At 15-year follow-up, the knee function further declines, resulting in an overall failure rate of 48.5%. DFVO provides longer lasting benefit in patients with better presurgical knee function.
Total knee arthroplasty following DFVO provides improved function and successful outcomes. Standard posterior stabilized components provide satisfactory stability after appropriate ligament balancing without the need for stemmed or highly constrained implants for most patients.
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Compared to the general population, patients who undergo total knee arthroplasty (TKA) after surgical fixation of a tibial plateau fracture have a...?
Higher risk for complications, similar patient reported outcomes, and similar satisfaction
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movement of the femur and tibia during flexion
Femur rolls back during flexion. The medial compartment remains stable, like a ball and socket joint, with the femoral condyle rolling back around the center of the medial side. In doing so, the femur externally rotates in flexion while the tibia internally rotates in flexion.
219
During the inflammation phase of bone healing after fracture, what is the role of bone morphogenetic proteins (BMPs)?
Induce host progenitor cell migration and differentiation at the fracture site
220
Stages of bone healing after fracture?
Bone healing after fracture involves 3 phases: inflammation, reparative, and remodeling.Inflammatory cell migration and proliferation into the fracture site, vasodilation and capillary ingrowth from the periosteum, and induction of host progenitor cell migration and differentiation at the injury site all occur during the inflammation phase of healing. During this time, BMPs are important in signaling host mesenchymal stem cells (progenitor cells) to the fracture site and stimulating differentiation into bone phenotype. Mechanical scaffold to assist in new bone formation is a process that occurs in the reparative phase when hyaline cartilage provides a scaffold for bridging fracture callus, which subsequently becomes calcified to bone by osteoblasts.
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Segond fracture
The Segond fracture, first described in cadaveric dissections by Paul Segond in 1879, is a lateral capsular avulsion fracture occurring just distal to the lateral tibial plateau. It is associated with tears of the anterior cruciate ligament in more than 75% of cases. Radiographically, this “lateral capsular sign” is easily identified on a standard anteroposterior view of the affected knee, but it also may be seen on a CT scan or MRI.
In 2013, a distinct, lateral capsular ligament known as the anterolateral ligament (ALL) was described. The ligament originates on the lateral femoral epicondyle and inserts on the anterolateral tibia. Claes and associates showed that the ALL inserts in the region on the proximal tibia from which Segond fractures consistently avulse, suggesting that a Segond fracture is actually a bony avulsion of the ALL.
222
In the United States, the Federal Highway Administration (FHWA) has designated 700 milliseconds as a safe threshold for braking reaction time. Based on this standard, surgeons should advise patients to return to driving how long after knee arthroscopy?
At least 1 wk later
-Hau and associates studied braking reaction time among patients after knee arthroscopy and compared these patients to healthy matched controls. Before undergoing surgery, patients in the surgical group demonstrated reaction times that were above the FHWA threshold (possibly because of the injury necessitating the surgery). At 1 week, the average reaction time increased to 920 milliseconds and dropped to 685 milliseconds by 4 weeks; this was still longer than the control group's reaction time, however.
223
According to the 2011 Oxford Centre for Evidence-Based Medicine (OCEBM) levels of evidence revision, a randomized trial with dramatic effect is categorized as which level of evidence?
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Step 2 (level 2)
-The 2011 revision to the OCEBM levels of evidence lists randomized trials and observational studies with dramatic effect as step 2 (level 2). This change was made to reserve step 1 (level 1) studies as systematic review studies that are “better at assessing strength of evidence than single studies and should be used if available.” Nonrandomized controlled cohort and case-series studies represent step 3 (level 3) and step 4 (level 4) levels of evidence, respectively.
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Heel pad atrophy
Heel pad atrophy, which causes deep, central heel pain whenever there is pressure on the heel, often occurs during the fifth or sixth decade of life and is more common in patients with diabetes. Corticosteroid injections into the heel, especially if done through a plantar approach, are considered a risk factor for atrophy of the heel pad. Heel pad atrophy is treated with external heel padding. A period of nonweight-bearing activity would be indicated for treatment of a calcaneal stress fracture. Although a calcaneal stress fracture could cause similar symptoms, it would be visible on the STIR images as an area of high-signal intensity in the calcaneus. The duration of this patient’s symptoms is unusual for plantar fasciitis, as is the central heel pain. Thickening of the plantar fascia is not seen on the PD image. Therefore, partial plantar fasciectomy is not indicated. Compression of the first branch of the lateral plantar nerve (Baxter’s nerve) causes tenderness on the medial aspect of the heel. Achilles tendon stretching and modalities are generally not helpful in heel pad atrophy.
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Indirect decompression in degenerative spondylolisthesis
In degenerative spondylolisthesis, indirect decompression of the spinal canal has been shown to be an effective treatment option. Malham and associates conducted a prospective study of 122 patients and reported an unplanned return to the operating room in 11 patients (9%). When reviewing these cases retrospectively, the authors felt that failure of indirect decompression should have been anticipated based on radiographic findings in 10 of these 11 patients who had high-grade, unstable spondylolisthesis or substantial bony lateral recess stenosis. Sato and associates reported an increase in the spinal canal area of 20%, whereas Castellvi and associates reported only a 9% increase. Park and associates reported that positioning the cage within the anterior one-third of disk space is better for achieving the restoration of the segmental angle without compromising the indirect neural decompression, if the cage was high enough.
226
ways to increase the flexion gap during TKA when the extension gap is OK?
Increasing the flexion gap without changing the extension gap can be performed by downsizing the femoral component or adding posterior slope to the tibia resection
227
what result does flexing the femoral component have during TKA?
Tightens the flexion gap only
228
When performing a posterior approach to the hip, which structure protects the anterior retractor from causing damage to the femoral neurovascular structures?
Psoas
-The psoas is the anatomic structure that runs anterior to the acetabulum. The femoral neurovascular structures are at risk if the retractor is placed anterior and inferior to the psoas tendon.
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A patient with medial compartment arthritis and a correctable varus deformity with no clinical or examination findings of knee instability most likely has an intact ACL. The pattern of medial compartment osteoarthritis most commonly associated with an intact ACL is that of anteromedial osteoarthritis. An incompetent ACL is commonly associated with a fixed varus deformity and radiographic signs of posteromedial wear. An incompetent ACL is a relative contraindication to a mobile-bearing UKA. When evaluating patients for a mobile-bearing UKA, a stress radiograph will allow the orthopaedic surgeon to determine the correction of the varus deformity and assess the lateral compartment. Inability to fully correct the deformity or narrowing of the lateral compartment with valgus stress should influence the surgeon against UKA. Joint registries across the world have shown decreased survivorship associated with TKA and UKA in men compared to other age groups, but survivorship is lower for UKA than TKA. No studies to date have shown differences in survivorship between fixed- or mobile-bearing UKAs. The complication that is unique to mobile-bearing UKA is bearing spinout, and this occurs in fewer than 1% of mobile-bearing UKA procedures. In vivo and in vitro polyethylene wear in mobile-bearing UKA is low. Arthritis progression may be faster for mobile-bearing UKAs than fixed-bearing UKAs.
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when performing Chevron osteotomy for distal humerus fractures, where is the optimal position on the ulna for the osteotomy site?
2cm distal to the triceps insertion in the bare area of the ulna
-The mean width of the olecranon bare area (lacking articular cartilage) is 0.53 cm (reference range, 0.13 cm-0.97 cm), and the mean distance from the triceps insertion to the corresponding area of the bare spot on the dorsal cortex is 2.1 cm (reference range, 1.4 cm-2.5 cm). Chevron osteotomy offers more inherent stability than a transverse or oblique osteotomy.
231
Which risk factor is most commonly associated with cuff nonhealing after repair?
Age older than 65
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P. acnes infection in shoulder surgery
Propionibacterium acnes is increasingly recognized as a pathogen in shoulder surgery of all types and a cause of postsurgical shoulder pain. Its presentation often is characterized by pain and only minimally elevated laboratory study results and low-grade clinical findings. Cultures should be held for 2 weeks to identify this organism.
233
external rotation lag sign (shoulder)
weakness of the shoulder external rotators and is consistent with a tear of either the supraspinatus or infraspinatus.
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O'brien shoulder test
Shoulder in 90 deg elevation, 15 deg adduction w/ downward pressure applied w/ arm in full internal rotation and external rotation.
-If pain with internal rotation, but relieved w/ external rotation, this is consistent w/ a SLAP TEAR
235
Indication for anatomic TSA?
End-stage GH arthritis w/ intact rotator cuff
236
Which factor contributes most to Orthopaedic outpatient satisfaction?
Surgeon empathy (strongest driver of patient satisfaction in the hand surgery office setting)
237
Which nerve dysfunction is responsible for lateral scapular winging?
Spinal accessory nerve (CN XI)
238
Which nerve dysfunction is responsible for medial scapular winging?
Long thoracic nerve (innervates serratus anterior)
239
Which deformity pattern is most commonly associated w/ talar neck fractures?
Extension and varus
- usually medial and dorsal comminution of talus (causing collapse into extension and varus through areas of comminution)
- malunion after ORIF as high as 32% w/ varus malunion most frequent
- correction of deformity involves lengthening of the medial column or shortening of lateral column of foot in conjunction w/ derogation of forefoot
240
When are concentrations of BMP-2 highest and when do they return to baseline when using induced-membrane technique (Masquelet)?
Peak concentrations occur at 4 wks and return to baseline around 6 months
241
Which muscles are in the superficial volar compartment of the forearm?
Pronator teres, FCRL, palmaris longus, FDS, FCU
242
Compartment measurements concerning for compartment syndrome?
Higher than 30mmHg or within 20-30mmHg of diastolic BP
243
Name the 4 muscle compartments of the forearm
Deep volar
Superficial volar
Mobile wad
Dorsal
244
What size plates are used for most diaphyseal radius and ulna fractures?
3.5mm plates and screws
245
What outcome measure score is typically used for lumbar spine problems?
Oswestry Disability Index Score (ODI)
246
What outcomes measurement score is typically used for cervical spine problems?
Neck disability index score (NDI)
247
2 most common locations for tarsal coalitions
Calcaneonavicular and talo-calcaneal
- sx include stiff and painful feet, rigid flatfoot
- 50% are bilateral
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Arthroscopic osteocapsular arthroplasty
removal of impinging osteophytes in elbow and release of hypertrophied capsule
-shown to be effective at relieving pain and improving motion in pts w/ OA
249
A fracture must exit the intermetatarsal articulation between the fourth and fifth metatarsals to be considered a Jones fracture
.
250
Jones fractures
- A fracture must exit the intermetatarsal articulation between the fourth and fifth metatarsals to be considered a Jones fracture
- associated with a 15-20% nonunion rate w/ nonsurgical care
- fixation with a solid screw is mechanically stronger than fixation with a cannulated screw
- nonunions or failure of hardware can be attributable to inadequate fixation or an unrecognized varus heel alignment leading to lateral column overload
251
when is posterior spinal fusion and instrumentation indicated for adolescent idiopathic scoliosis
when curves are larger than 50 degrees
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what is the preferred treatment for skeletally immature adolscenet girl with a 26 deg curve?
Full time thoracolumbosacral brace wear at least 13 hours per day
253
The Joint Commission recommends washing hands with soap and water for a minimum of how many seconds when they are visibly soiled and contaminated?
15 seconds
254
what 2 autogenous bone grafts are osteogenic, osteoinductive, and osteoconductive?
- Iliac crest bone grafts
| - Bone obtained from IM canal via the reamer irrigator aspirator system
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osteoconductive
has "structure"
256
bone marrow aspirate
osteogenic and osteoinductive
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demineralized bone matrix
osteoinductive (has BMPs) and osteoconductive (has structure)
258
Ceramics
osteoconductive only
259
BMPs
osteoinductive
260
allograft bone
osteoconductive
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For chronic injuries of the superficial peroneal nerve that are resistant to nonsurgical treatment, the treatment of choice is neurotomy with transposition into bone.
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262
A mallet toe
- flexion deformity at the level of the distal interphalangeal joint of the second toe. These can be flexible or rigid. Flexible deformities can be treated with flexor tenotomies. Rigid deformities typically require a DIP joint fusion.
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flexible hammer toe treatment
FDL transfer to the extensor hood
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multidirectional shoulder instability (MDI)
- Symptoms are typically of insidious onset with nonspecific sports-related pain during the second or third decade of life
- etiology of MDI involves a patulous inferior capsular complex, but, in isolation, this lesion may not produce symptoms
- Patients with MDI have abnormal patterns of rotator cuff muscle activity that is not restored with nonsurgical treatment. Symptomatic patients with MDI also demonstrate increased rates of abnormal scapular kinematics. The prevalence of MDI is higher among overhead athletes
- Physical therapy for strengthening of the rotator cuff and scapular stabilizers remains the recommended initial treatment
- Rehabilitation should continue for at least 6 months (and possibly much longer)
- If nonsurgical measures fail to provide adequate relief, arthroscopic capsular plication is a viable treatment option, with high rates of return to play among properly selected patients
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Augmentation of a Broström repair with the mobilized lateral portion of the extensor retinaculum (Gould modification) is expected to produce
- no significant biomechanical difference in initial ankle stability
- Essentially, the Gould modification shows no difference in any outcomes (pros or cons)
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2-incision distal biceps repair associated complicatons
heterotopic ossification with a radial-ulnar synostosis is a concern. This complication can be minimized through irrigation of bone debris and care to avoid dissection between the radius and ulna
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single-incision distal biceps repair associated complications
lateral antebrachial cutaneous nerve is retracted during the procedure. Numbness on the lateral side of the forearm is common, although often temporary
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arthroscopic debridement for lateral epicondylitis associated complications
injury to the radial UCL can occur, leading to posterolateral rotatory instability of the elbow
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modified Jobe technique for UCL reconstruction associated complications
typically involves an ulnar nerve transposition during the procedure. Numbness and tingling in the fourth and fifth digits are concerns when this procedure is performed
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2 most common associated complications with single incision distal biceps tendon repair
- lateral antebrachial cutaneous nerve palsy (from retraction)
- PIN palsy (from the button)
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Note that it is "preferable" to allow a patient to regain full motion before ACL reconstruction. Thus, in peds population, the test answer is perform ACL reconstruction when motion and gait are normal, NOT as soon as possible
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272
what is the most common zone of the growth plate injured?
the HYPERTROPHIC zone (weakest point)
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Discoid meniscus surgical intervention
based on symptomatic patients. Complete discoid menisci are typically stable but are expected to have >4.5 times incidence of surgical intervention. Saucerization of symptomatic discoid meniscus is associated with better results with younger patients with increases of poor outcomes in adult-aged patients. Meniscal transplant may be an option, although long-term results are unknown.
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stable OCD lesion treatment
An initial period of nonsurgical treatment is recommended for an intact lesion in a skeletally immature patient. Surgical treatment varies but is not indicated until failure of nonsurgical treatment. Observation is not likely to lead to symptom relief.
-they should undergo activity modification and decreased weight bearing
275
what is the treatment of unresolved Osgood-Schlatter disease in a symptomatic skeletally mature individual?
-Ossicle resection and tibial tubercleplasty
276
which ligaments provide the most restraint to posterior translation of the AC joint and must be preserved during a Mumford (distal clavicle excision) procedure?
The posterior and superior AC ligaments
277
ACL bundles and when they are tight or loose
ACL: posterolateral and anteromedial bundles
- anterior bundles tight in flexion
- posterior bundles tight in extension
278
what is the main function of the anteromedial bundle of the ACL?
-resists anterior translation during knee flexion
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what is the main function of the posterolateral bundle of the ACL?
-resists rotatory loads during knee extension
280
when should a coracoid transfer or distal tibial allograft reconstruction be used for bony bankhart lesions that have failed non-op tx?
anterior bony deficiencies occupying more than 25-30% of glenoid joint surface
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Olsen and associates demonstrated a 5-fold increase in overuse injuries of the shoulder and elbow in pitchers who threw more than 8 months of the year. This represented a stronger risk factor than pitch count in predicting injury. Although curveballs and other breaking pitches have long been thought to cause injury in younger pitchers, this study found no correlation between the age at which a breaking ball is first thrown and risk for an injury that will necessitate surgery. A UCL reconstruction would not be indicated in this setting prior to a more complete evaluation and trial of nonsurgical treatment. A disturbingly high percentage of coaches and athletes perceive UCL reconstruction to be an effective procedure in enhancing performance in an uninjured elbow.
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Valgus extension overload
characterized by reproducible pain that is elicited by repeatedly forcing the elbow into terminal extension while applying a valgus stress to the elbow. A common examination finding is pain at the posteromedial tip of the olecranon process. If rest from throwing, followed by gradual return to throwing through an interval throwing program, fails to provide relief, surgery that usually involves osteophyte excision at the posteromedial tip of the olecranon may be performed. The most common reason for repeat surgery is medial instability, which was reported in as many as 41% in 1 series. Avoiding overresection of the olecranon is necessary to minimize this risk. The adjacent lesion on the medial ulnotrochlear joint can be addressed simultaneously.
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Femoroacetabular impingement (FAI)
FAI is a common cause of hip pain in the young athlete. FAI can manifest in three types: cam type, pincer type, or mixed cam/pincer type. Patients typically present with anterior groin pain, which is worse with flexion and rotation of the hip.
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Posterior shoulder instability
- rare form of instability that often presents with pain rather than feelings of instability
- It often occurs in young athletes during activities that put the shoulder in an “at-risk position” (flexion, adduction, and internal rotation). Repetitive microtrauma can lead to posterior shoulder instability such as seen in football linemen. Swinging a bat or golf club places the lead arm in a flexed, adducted, and internally rotated position, which can lead to posterior translation of the humeral head that is forcibly reduced in follow-through
- Of the 4 rotator cuff muscles, the subscapularis is most important at preventing posterior subluxation.
- The most common complication seen after arthroscopic posterior labral repair is stiffness, followed by recurrent instability and degenerative joint disease.
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Varus producing high tibial osteotomy
The technical options include a medial opening-wedge or a lateral closing-wedge osteotomy. Both techniques have advantages and disadvantages; however, a medial opening-wedge osteotomy is contraindicated in a smoker because of concern for nonunion. As a result, current smoking history is the only factor listed that would influence the technique used. The history of prior arthroscopy has no relevance in the decision about which type of osteotomy is appropriate. Normal BMI is between 18.5 and 24.9, so this patient’s BMI is considered normal and would not affect the surgical technique (if this patient were obese, a lateral closing-wedge osteotomy would be considered, but this is controversial). His age of 40 years is an indication for HTO but does not influence technique
286
What is the most common reason for hip arthroscopy revision that addresses femoroacetabular impingement?
Persistent femoroacetabular impingement
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PCL bundles
Anterolateral (tight in flexion) and posteromedial (tight in extension)
288
which compartments see degenerative changes in PCL deficient knees
Because of alterations in knee kinematics and increased varus alignment in PCL insufficiency, contact stresses and cartilage loads increase in the patellofemoral and medial compartments
289
most common complication with single incision distal biceps repair?
Numbness on lateral side of forearm from LABC nerve retraction
290
cartilage defect thresholds for microfractures vs osteochondral allografts (OATS) vs autologous chondrocyte implantation (ACI)
OAT is associated with better results than microfracture for medium-sized lesions between 2 cm and 4 cm, while autologous chondrocyte implantation yields better improvement for patients with defects larger than 4 cm.
291
histology of articular cartilage
The superficial layer or lamina splendens contains a small amount of proteoglycan with collagen fibrils arranged parallel to the articular surface. In contrast, the deep zone contains the largest-diameter collagen fibrils, oriented perpendicular to the joint surface, and the highest concentration of proteoglycans.
292
femoral neck stress fractures
overuse injuries commonly found in athletes who have experienced an increase in their training regimen. Tension-sided femoral neck stress fractures often are treated with closed reduction and percutaneous pinning, whereas compression-sided stress fractures often are treated with protected weight-bearing activity and crutches with gradual resumption of activity.
293
MPFL reconstruction, what happened if graft is too tight in greater degrees of knee flexion?
If the graft becomes tighter with knee flexion, the femoral attachment is too proximal. This error is referred to as “high and tight,” meaning that a high or proximal femoral attachment produces a graft that is too tight with knee flexion. If graft tension increases with increasing knee flexion, the result is loss of knee flexion or graft failure, increased contact forces resulting in patella femoral chondrosis, and possibly medial subluxation.
294
non-op management rehab for PCL injury
- Treatment should consist of relative protection for 10 to 14 days followed by early range of motion and gentle closed-chain quadriceps strengthening.
- Isolated grade 1 and grade 2 posterior cruciate ligament injuries can be successfully managed nonsurgically. Progression to global knee strengthening can begin 4 to 6 weeks after the injury, with return to functional activity when full range of motion and strength is established.
- Hamstring strengthening should be avoided until the ligament has healed (4 to 6 weeks) because the posterior force on the tibia will stress the injured posterior cruciate ligament. Immobilization may be used for a short time to allow swelling and pain to subside, but early range of motion is preferred to avoid unnecessary stiffness following the stable injury.
295
primary treatment for locked bucket-handle medial meniscus tear?
Primary treatment should be excision
296
What factor highly correlates with poor outcomes after surgery for femoroacetabular impingement?
Tonnis grade 2 (measure of OA)
-A systematic review of case studies looking at the results of surgical treatment for femoroacetabular impingement shows good results for most patients, with the exception of those with preoperative radiographs showing osteoarthritis or Outerbridge grade III or grade IV cartilage damage noted intraoperatively. Both Byrd and Jones and Philippon and associates have shown good surgical results for this condition among professional athletes. Likewise, Fabricant and associates demonstrated good surgical results among adolescent patients with an average age of 17.6 years.
297
What is the most common complication associated with distal clavicle resection for AC joint osteoarthritis
Persistent pain
-resection of 10 mm or more of the distal clavicle may lead to instability of the AC joint, especially if the AC capsule is sectioned.
