Questions Flashcards
what zone does gigantism and achondroplasia affect? how about for fractures?
- zone of proliferation
- remember it goes reserve (gauchers)
- hypertrophy (fractures
bone is weakest with ___ forces and strongest against ___ forces
shear (NOT tension); compression
X-linked rickets:
- what is the Ca level?
- what is the phosphate level?
- what is the gene?
- it is the most common form of ___
- what is PTH?
- Normal
- Low
- PHEX
- hereditary rickets
- Normal; it would be high with nutritional rickets
how does induction coupling work? what is this seen with for treatment of nonunions?
-stimulates osteoblasts, increases expression of BMP-2, BMP-7, and tgf-beta
-bone stimulators
IT DOES NOT CHANGE OSTEOCLAST FUNCTION
What is the cell lineage for osteoblasts? osteoclasts?
- mensenchymal stem cells
- hematopoetic stem cells from macrophage lineage
what is the gene for x-linked rickets?
what is the gene for Osteogensis imperfecta?
- PHEX
- COLIA1, COLIA2
what are the functions of protein C/S?
they inhibit the coagulation cascade thus deficiencies in them would cause increased amounts of clotting; also remember that warfarin first inihibits them quicker than the coag factors thus you have a brief hypercoagable state when started it
what molecule is released during surgical dissection that increases coagulation?
thromboplastin which activates factor VII which activates factor X and then activates factor II (prothrombin to thrombin)
what is the mechanism of enoxaparin?
aka lmwh that activates antithrombin III and forms a complex that binds to Xa and prevents Xa from converting II to IIa (prothrombin to thrombin)
tell the activity of TA and Gastroc during toe off, swing and heel strike
- TA: dormant, concentric to clear the toes from the ground, eccentric to lower the foot
- GC: concentric during toe off, dormant during swing, and eccentric during flat foot as the bodyweight transfers
what diseases are included when testing blood for transfusions?
HIV 1 and 2, west nile, hep B and C, syphilis
what is the inheritance for becker’s and duchenne muscular dystrophy?
x-linked recessive
Anisotropic vs isotropic?
Mechanical properties change depending on the orientation of the stress vs those that don’t; examples of anisotropic are menisci, cartilage, cortical/cancellous bone and isotropic would be implants
- nitrogen containing bisphosphonate
2. non-nitrogen containing bisphosphonate
- inhibit GTPase formation which prevents GTP prenylation
2. cause apoptosis with ATP analogs
what is the function of denosumab?
human monoclonal antibody that binds to RANKL
use of topical vancomycin decreases ___ but increases ___
- SSIs
- gram negative infections as the positive goes down
BMP 2 is approved for ____ with fixation via ___ while BMP 7 is approved for ____
- open tibial shaft fixed with IMN within 14 days of initial injury
- long bone nonunions
what are the 3 principal layers of the growth plate? what does gigantism affect?
- reserve, proliferative, hypertrophic
- proliferative
what happens to the cartilage of a limb that is NWB and what happens to the contralateral limb during that time?
-thinning to NWB and no changes to contralateral side
what is the initial abnormality and phase with paget’s disease?
it starts with increased bone remodeling and turnover that is abnormal with increased osteoclast absorption; there is then a mixed phase followed by sclerotic phase where the osteoblast dominates
fibrin is an end product of the ___ ____ and is factor ____ formed from ____
- coagulation cascade
- IIa
- thrombin
Sclerostin and DKK-1 downregulate what pathway? what does this result in?
- wnt/beta-catenin via the LRP 5/6 receptor
- osteoblast formation
what is the most common pathogen with cat bites? dog bites?
- pasteurella multifoca
- pasteurella canis
what are the 3 stages of tendon healing?
what is the weakest?
- inflammatory, proliferative, and maturation
- inflammatory
Deep zone of cartilage has ____ fibers and ____ proteoglycans; superficial zone has ___ fibers and ___ proteoglycans
- perpendicular
- high
- parallel
- low (more water)
Osteocytes communicate in the lacunar network through ____; what is the in the haversian canals? what connects the canals?
- canaliculi
- blood vessels
- volkmann’s canals
what is the small part of the C-arm? what is the large part? which has more radiation exposure?
- source is the small side and the intensifier is the large side
- the source
what is the function of decorin?
-proteoglycan that helps regulate fibril size in collagen
what allows staph epidermidis to adhere to surfaces?
forms a biofilm/glycocalyx that lets it attach to the implants which helps it to resist phagocytosis
what type of collagen is primarily made during the inflammatory early healing phase? what about later?
- type III
- type I
BMP 2 is approved for ____ tibial shaft fractures while BMP 7 is approved for ___ tibial shaft fractures
- acute, open
- closed nonunion
what does viscoelastic mean?
stress-strain curve is time/rate dependent; example being ligaments
go through the 4 types of allergic hypersensitivities
search on orthobullets
Modulus of elasticity: what is this a measure? the higher the modulus the ___ a material is, list common implants relative to cortical bone
- stress/strain curve of a material reflects the stiffness
- stiffer
- cortical bone - titanium - stainless steel - cobalt chrome - ceramic
Gout is ___ birefringement with ____ shaped crystals with pseudogout being ____ birefringement with ____ shaped crystals
- negative
- needle
- positive (remember P and P)
- rhomboid
locking screws have ___ axial strength vs cortical fixation and ___ torsional
- increased
- decreased
With age, water content and proteoglycan synthesis ____
decrease (remember as you age meat it dries out)
what is the most common bacteria for necrotizing fasciitis?
Group A strep
RB-1 and p53 are examples of ___ ___ ___
tumor suppressor genes
in someone that breaks out in a rash from hyaluronic acid injections into their knee would have what allery?
- chicken/egg products (rooster comb)
JIA: what is the difference between the arthritic joint symptoms with this compared to lyme disease? are serologic tests helpful? what is the opthalmologic complication that is seen?
- poly-articular vs monoarticular
- not as helpful
- uveitis
Muscle fibers: I? IIa? IIb? which are recruited first? which are larger?
- slow and oxidative
- fast and oxidative-glycolytic
- fast and glycolytic
- I
- IIa/b
Fretting corrosion is from ___ while galvanic corrosion is from ___
- micromotion commonly seen with modular implants
- dissimilar metals
what layer of articular cartilage are progenitor cells found in?
superficial (more water, less proteoglycans, parallel to joint surface for orientation of fibers)
Osteoporosis treatment: what is the % for osteoporosis to be diagnosed for FRAX over 10 year period for hip fracture and major osteoporotic fracture? who should receive antiresorptive therapy?
- 3% and 20%
1. prior hip fracture or vertebral fracture
2. T score < -2.5
3. T score -1.0 to -2.5 and FRAX over 3% or 20% for the above parameters
what osteoporosis medication has been shown to cause osteosarcoma in small amount of animal studies but not humans?
what are the contraindications to this use?
- recombinant PTH (forteo)
- hx of osteosarcoma, paget’s disease, hypercalcemia, pregnancy, metastatic disease
Chief cells secrete ___ while parafollicular cells secrete ___
- PTH
- calcitonin
what are the 2 types of vitamin D deficient rickets and what causes them?
type 1: deficiency in the hydroxylase enzyme that is found inthe kidney and converts to 1, 25 (OH)2
type 2: mutation that causes the receptor to be inactive for 1,25 (OH)2
what factor is fibrin? what breaks it down? what prevents this from being activated?
- IA
- plasmin
- TXA
what is the MecA gene and what bacteria most commonly has it?
- alters the penicillin binding protein and gives resistance for beta-lactam antibiotics
- MRSA
PCNs and cephalosporins inhibit ____ which prevents ____, fluoroquinolones inhibit ___ ___
- transpeptidase enzyme
- cross-linking of polysaccharides that inhibits cell wall synthesis
- DNA gyrase
what is the oral class of abx that covers pseudomonas? p acnes?
- fluoroquinolones as well as generation 4 cephalosporins
- clindamycin
Sclerostin: produced by ____, downregulates what pathway? increasing levels would have a ___ in overall bone mass, ___ the production of osteoblasts
- osteoblasts
- wnt pathway
- decrease
- decrease
what are CAMs? what CAM helps mets attach to the endothelial? which helps them detach and get into the blood stream?
- cell adhesion molecules
- integrin
- E-cadherin (E for escape)
what is the most common organism with soft tissue infection of the foot with puncture wound? what if they then get osteomyelitis?
- S. aureus
- Pseudomonas
what is the inheritance pattern for hemophilia A and B?
- x-linked recessive
what is left intact with sunderland type II peripheral nerve injury (axonemetesis)? name 2 things that are disrupted
- endonerium, perinerium and epineurium
- schwann cell and myelin sheath
Scurvy: ____ epiphysis and bleeding from ___, from ___ mutation that affects procollagen
- ringed
- gums
- hydroxy lysine
___ is the proteoglycan that is responsible for water binding in type II cartilage
- aggrecan
Cartilage zones: superficial? middle? deep?
- parallel, highest water to proteoglycan ratio
- oblique orientation with less water and more proteo
- perpendicular and most proteoglycans
what molecule contributes to viscosity of joint fluid most? joint is non-___, synovial fluid is made by ___ cells
- hyaluronic acid/mucin
- newtonian as it becomes less viscous with stirring
- type B
Cartilage and Arthritis: OA proteoglycans ___ and water content ___, aging has ___ water content which increases the ____ and ____ AGEs
- decreases
- increases (wet and weak)
- decreased
- modulus of elasticity
- increased
etanercept ___, anakinra ___, tocilizumab ___, rituximab ___
- TNF-alpha
- IL-1
- IL-6
- B cell antibodies
what is the most sensitive and specific test for RA?
- anti CCP
HIT and transfusion reactions are what type of HS? how about sick sinus? type I is ___ mediated and immediate such as a ___ allergy commonly seen in pediatric patients with ___, type IV is ___
- II
- III
- IgE
- latex
- myelomeningocoele
- delayed hypersensitivity
what is the gene in MRSA that gives it the PCN binding protein that gives it resistance?
- MecA
MRSA nasal positive has how much higher post op infections with total joints? how do you treat?
- 2-9x
- intranasal mupuricin x 5 days BID, vancomycin preop and chlorhexadine showers
DMARDs can be ____ while biologics are stopped ___ week preop and restarted ___ post op (this is AAHKS in 2017)
- continued
- 1
- 2
what are the superantigens for MRSA and GAS? these both can lead to ___ ___
- TSS toxin-1 and M protein
- cytokine storm
what organism with MSK infection in children < 5 years old after upper respiratory infection? most common septic arthritis in young sexually active patients? what does the gram stain show?
- kingella
- N. gonorrhea
- gram negative diplococci
DVT/PE: what is the final product of the clotting cascade? what does this then activate? what is the test of choice? what is the recommendation for contact sports being treated for VTE on anticoagulation?
- IIa (thrombin from prothrombin)
- fibrin from fibrinogen
- CT PE protocol/spiral CT
- not allowed to play
fat emboli syndrome: what is the triad? usually after asymptomatic period after ___, ___ ___ on CXR and ___ ___ on CT chest
- petechial rash, neurologic syndromes, pulmonary collapse from ARDS
- long bone fractures
- snow storm
- ground glass
Hypovolemic shock: go through the grades I-IV and the percentage of blood loss and findings at each
- I: 0-15%, normal VS
- II: 15-30%, tachycardia but normal BP
- III: 30-40%, tachycardia, decreased BP, decreased urine output
- IV: > 40%, tachycardia, decreased BP, decreased urine output, tx with PRBCs
duchenne muscular dystrophy have higher rates of ___ ___ during surgery and this is treated with ___, what is the earliest sign?
- malignant hyperthermia
- dantrolene
- rising end tidal CO2
what percentage of type I collagen are tendons?
- 95%
what is the mechanism of corticosteroids?
- inhibition of phospholipase A2 which prevents the conversion of phospholipids to inflammatory mediators
what is the treatment for asymptomatic paget’s disease? what is first line for symptomatic? what would be second line?
- suppurative therapy
- bisphosphonates
- calcitonin
what do ginkgo, garlic, and ginseng affect? st john’s wart would affect metabolism of what?
- platelets
- warfarin
Renal osteodystrophy: PTH? Ca? PO4?
- increased
- decreased
- increased
what % of BMD must be lost before you can see it on plain radiographs?
- 40%
Factor V Lieden: factor ___ is usually inhibited by ___ __ but with this it is not, it is a cofactor for ___ and thus excess fibrin is made and a ___ state occurs
- V
- protein C
- Xa
- hypercoagable
Anticoagulation review: fondaparinux? rivaroxaban? heparin? ASA? TXA?
- indirect Xa
- direct Xa
- promotes activation of antithrombin III which inhibits IIa (thrombin), Xa, and III
- inhibits the activation of thromboxane A2 in platelets
- prevents the activation of plasmin from plasminogen which breaks down fibrin clots
Antibiotics with ribosomes: buy AT 30, CELL at 50
- aminoglycosides (gent and tobra), tetracyclines
- chloramphenicol, erythromycin, linezolid, cLindamycin
what is the acronym for DNA/RNA/protein tests?
SNOW (southern, northern, nothing, western) : DROP (DNA, RNA, nothing, protein)
what happens to the following with a PE: arterial co2, arterial o2, A-a gradient, what is seen on EKG?
- down
- down
- increase
- RBBB
what is the function of rituximab? name all of the TNF alpha inhibitors?
- CD20 antibody
- etanercept, infliximab, adalimumab, golimumab (I-AGE without my medication)
