Bone Science
What is the main inorganic compound in bone?
Calcium hydroxyapatite
What is the name for the cartilage that forms after microfracture procedure and what type of collagen does it contain?
Fibrocartilage
Type I collagen
Describe the difference between incidence and prevalence
Incidence = new cases within a certain time frame
Prevalence = all cases at a certain point (new or already diagnosed)
What is the most common type of fragility fracture?
Vertebral compression fracture
What gene is associated with psoriatic arthritis?
HLA B27
Actually only present in 50% of cases
What is the inhibitor of RANKL that downregulates osteoclasts?
Osteoprotegrin
Name the two sources of blood supply/nutrient delivery to articular cartilage?
Synovial fluid
Subchondral bone
What's the difference between a type I and type II error?
Type I = saying there is a difference when there isn't
Type II = saying there is no difference when there actually is a difference
What is the difference between T score and Z score for DEXA scan?
T score = compared to normal 30 year old bone
Z score = compared to those of the same age
What is the most sensitive and specific lab test for rheumatoid arthritis?
Anti-CCP
Name the major osteolytic enzyme used by osteoclasts
How does water content in articular cartilage change in normal aging versus in osteoarthritis?
Aging = water content decreases
Osteoarthritis = water content increases
What is the equation for calculating power?
Power = 1 - beta
beta = probability of a type II error
What is the name of the medication that is an Ig2 monoclonal antibody against RANKL?
Denosumab (Prolia)
Name the two first-line medications for an acute gout flare?
Indomethacin or colchicine
Steroids are reserved for those who cannot take NSAIDs or colchicine
What is secreted by osteoclasts to decrease the pH to make calcium hydroxyapatite more soluble?
Tartrate resistant acid phosphate (TRAP)
In the relation to the joint line, describe the change of orientation of collagen fibers from deep to intermediate to superficial layers of articular cartilage
Deep = perpendicular to the joint
Intermediate = oblique or random
Superficial = parallel to the joint
Positive likelihood ratio = sensitivity/(1 - specificity)
Why are patients with renal osteodystrophy hypocalcemic?
The damaged kidney cannot convert vitamin D3 to calcitriol (active form of vitamin D)
And because of phosphate retention from kidney failure
What exam test is required every 4-6 months for patients with juvenile idiopathic arthritis?
Slit-lamp examination
Progressive iridocyclitis can lead to rapid loss of vision if not treated
What are the progenitor cells for the following:
Osteoblast
Osteocyte
Osteoclast
Osteoblast = undifferentiated mesenchymal cell
Osteocyte = osteoblast
Osteoclast = myeloid hematopoietic cells from monocyte/macrophage lineage
Describe changes in chondroitin 4 sulfate and keratin sulfate in aging and then in osteoarthritis
Aging: decreased chondroitin 4 sulfate and increased keratin sulfate
Osteoarthritis: increased chondroitin 4 sulfate and decreased keratin sulfate
When criteria for a dataset to be analyzed using ANOVA (analysis of variance)?
Parametric vs nonparametric
Continuous vs categorical
Number of groups
Parametric
Continuous
3 or more groups
Farnesyl pyrophosphate synthase
What is the eponymous name of the syndrome with rheumatoid arthritis associated with splenomegaly and leukopenia
Felty's Syndrome