Lecture 1: Osteoarthritis Flashcards
T/F
The diarthrodial joint is considered an organ
True.
Describe the diarthrodial joint
synovial joints allow for motion and are complex
synoviocytes line the membrane
think of it as an organ
What does poor lubrication of the joint lead to?
increased friction, which results in increased wear and tear on the joint
What causes joints to wear out over time?
trauma
disease
biochemical changes in articular cartilage
poor lubrication
What are the 2 functions of the synovium?
lubrication
phagocytosis
What do synoviocytes add to the joint fluid?
glycosaminoglycans
hylauronon
What is the synovial fluid?
dialysate of blood- ultrafiltrate
What are the 2 functions of the synovial fluid?
lubrication and and nutrition of the articular cartilage
Describe normal healthy joint fluid:
sticky, has viscosity to it
diseased is watery
What is the chief glycosaminoglycan? what does it contribute to the joint fluid?
hyaluronic acid (HA)
gives it its viscocity
Osteoarthritis can occur if HA is in low _____ and _____
quality and/or quantity
T/F
Articular cartilage is highly vascualr but has no innervation
FALSE
it is avascualr, and has no innervation
Chondrocytes receive ____% of their nutrition from synovial fluid and ____% from subchondral bone.
90-93% from fluid
3-10% subchondral bone
What type of collagen is present in articular cartilage?
TYPE II
Describe the realtionship between HA and proteoglycans
HA is the protein backbone and attached to it are proteoglycans
Think of HA as the terminal and proteoglycans as the planes docked to it
Define weeping lubrication:
occurs when cartilage is compressed, ie during movement
Define boosted lubrication:
when fluid is sucked back into the cartilage
Define boundary lubrication:
binds to superficial cartilage to help with movement
______ depletion compromises lubrication
proteoglycan
Define osteoarthritis:
non infectious degeneration of articular cartilage
What are physical changes associated with OA?
bone formation at synovial membrane
periarticualr fibrosis (joitn thickening
What is OA associated with an infection referred to as?
Septic OA
What are the clinical sign associated with OA
exercise intolerance
shortened stride
lameness/head bob or bunny hopping
behavior changes
visual/palpable joint effusion
Humans tend to get ______ OA while animals typically get ______ OA
primary
secondary
What causes secondary OA?
developmental and bone diseases
ligament dz- abnormal stability
articular function- inflammation causes damage
infection
trauma
surgery can too
What is the viscous cycle of OA?
poor lubrication
cartilage fibrillation-> fissures
inflammation/release of ILs/Cytokines/collangenasee/elastases
Depletion of matrix proteoglycans
damage to collagen network
RESULTS in cartilage degeneration-> poor lubrication etc etc
What is the net result of OA?
articualr fibrilation cartilage loss subchondral sclerosis osteophyte formation periarticular fibrosis synovitis pain/loss of fx
T/F
OA effects the entire joint but may be pronounced more so in one area
TRUE
What are the radio graphic signs of OA
increased soft tissue opacity in the joint space
periarticualr bone formation
subchondral bone sclerosis
T|/F
Radio graphs typically overestimate the severity of OA and therefore do not correlate clinically with function
FALSE
They tend to underestimate severity
If the ______ is addressed, we can help slow OA
Primary problem
Once you have diagnosed OA, what do you tell the owner?
We can try some tx to help make sparky more comfortable
T/F
There is no cure for OA
TRUE
T/F
Once OA starts it will continue to progress; the best we can do is address the primary problem, and try ti mitigate further damage
TRUE
What are the 4 forms of medical management of OA
Weight management
Excercise moderation
Chondroprotectives
NSAIDS
What is the goal of weight management? what is it based on?
Lean and fit
based on Lab experiments
What are the 3 parts to exercise management?
controlled
low impact
rehab
What are some examples of chondroprotectives?
Glucosamine Chondroitin sulfate Manganese ascorbate ASU MSM Omega 3 FA
What are polysulfated glyosaminoglycans?
Adequan
from bovine tracheal cartilage
IM injection 2x weekly for up to 4 weeks
Not clinically shown
Why might Hyaluronon injections be beneficial to slowing cartilage degredation
Leaves joint completely in 24 hours, unknown mech of action
had no effect on OA progression or loading in canine stifles
How does injection of platelets into joint help combat OA?
increases cytokines and growth factors
NSAIDS act to:
inhibit cyclooxygenase pathway
effect many systems
be careful of side effects
T/F
for best results tx OA with 2 NSAIDS
FALSE
never more than 1
____ days for washout between NSAID
____ days for washout for asprin
4-7
7-10
At what point to you opt for surgery with OA and what is the main goal of it?
when medical management has failed
unlikely to have addressed primary cause
Surgery is to address primary
T/F
cartilage healing is generally fast
FALSE
poor blood supply
What is micropicking?
allows blood flow from subchondral bone
encourage fibrocartilage formation
blood clot/fibrocartilage fill in so bone isnt as exposed
What is osteochondral transplant surgery?
large lesion
bone plug insrted into defect supports subchondral bone
What is the single most important factor to remember when treating OA in small animals?
OA IS SECONDARY IN NATURE
T/F
OA in humans, as with animals is typically secondary in nature
FALSE
primary in humans
T/F
Radiographic signs of OA are fairly consistent with clinical function
False
NO correlation
T/F
medical management is important for tx of OA
TRUE
