Osteoarthritis Flashcards
Joints wear out over time due to what 4 factors?
- Trauma
- Disease
- Biochemical changes in articular cartilage
- Poor lubrication
Poor lubrication of a joint results in increased ___.
Friction
Lubrication is affected by what factors?
- Synovial membrane
- Physical and chemical properties of synovial fluid
- Load on the joint
- Type of joint movement
- Geometry of articular surfaces
What are the 2 functions of the synovium?
- Lubrication (adds glycosaminoglycans to synovial fluid & absorbs hyaluronan)
- Phagocytosis
Synovial fluid is a ___ of blood.
Dialysate
What are the 2 functions of synovial fluid?
- Lubrication
2. Nutrition to articular cartilage
What is the major glycosaminoglycan of synovial fluid?
Hyaluronic acid
True or False: Hyaluronic acid has a low molecular weight.
FALSE: High molecular weight
Hyaluronic acid provides ___ to the synovial fluid.
Viscosity
When hyaluronic acid is low in quality or quantity in the synovial fluid, what are you at risk of developing?
Osteoarthritis
True of False: Articular cartilage is avascular, without lymphatics, but is innervated.
FALSE: Articular cartilage is avascular, without lymphatics, but is NOT INNERVATED.
Chondrocytes get the majority (90-93%) of their nutrients from what?
Synovial fluid
How much of articular cartilage is made up of water?
70-80%
What are the 5 components of articular cartilage?
- Water (70-80%)
- Type II collagen fibrils
- Hyaluronic acid
- Chondrocytes
- Proteoglycan molecules
What is the most important type of lubrication for synovial fluid, weeping, boosted, or boundary?
Weeping
Proteoglycan depletion compromises ____.
Lubrication
Osteoarthritis is a _____ degeneration of articular cartilage.
Non-infectious
What are the 3 components of osteoarthritis?
- Non-infectious degeneration
- Periarticular fibrosis
- Osteophytes
What are the 5 signs of osteoarthritis?
- Exercise intolerance
- Shortened stride
- Lameness/bunny hop
- Behavior change/aggression
- Joint effusion
The majority of OA cases in dogs are due to primary or secondary causes?
Secondary
What is the first step of the vicious cycle of OA?
Poor lubrication
What is the second step of the vicious cycle of OA?
Cartilage fibrillation
What is the third step of the vicious cycle of OA?
Inflammatory mediator release
What is the forth step of the vicious cycle of OA?
Depletion of matrix proteoglycans
What is the fifth step of the vicious cycle of OA?
Damage to collagen fibril network (increase in MMPs and aggrecanase)
What is the RESULT and final step of the vicious cycle of OA?
Cartilage degradation
What are the 6 results of the vicious cycle of OA, including cartilage degradation?
- Cartilage loss (degradation)
- Periarticular fibrosis
- Synovitis
- Osteophyte formation
- Articular fibrillation
- Subchondral sclerosis
What are the radiographic signs consistent with OA?
- Increased soft tissue opacity within the joint space (consistent with joint fluid)
- Periarticular new bone formation (osteophytes)
- Subchondral sclerosis
True or False: Radiographic signs do not correlate with clinical function of an osteoarthritic patient.
TRUE
True or False: There is no cure for OA.
TRUE - once it starts, it will progress
What are the 3 keys to management of secondary OA?
- Treatment of the primary cause
- Decreasing the inflammatory response
- Maintaining cartilage health
What are the 4 options for medical management of OA?
- Weight management
- Exercise moderation
- Chondroprotectives
- NSAIDs
What are the 3 components of physical rehabilitation?
- Promote joint health through MOBILITY
- Maintain and improve MUSCLE MASS
- Prevent periarticular contraction
Glucosamine is a precursor to ____.
GAGs
Glycosamine stimulates the synthesis of what?
HA
Chondroitin sulfate inhibits ___.
MMPs
Chondroitin sulfate stimulates the synthesis of ____ and ____.
GAGs and collagen
Which chrondroprotective is responsible for resiliency of cartilage?
Chondroitin sulfate
Which two chondroprotectives are COX-independent anti-inflammatory?
- Glycosamine
2. MSM
Which condroprotective has anabolic effects on cartilage?
Avacado/soybean unsaponifiables (ASU)
Avacado/soybean unsaponifiables suppress the production of what?
MMP
From what is the PSGAG Adequan obtained?
Brovine tracheal cartilage
Adequan is a ____ injection twice weekly for up to 4 weeks.
Intramuscular
What is the function of Adequan?
Slows cartilage degradation
What type of injection is hyaluronan?
Intra-articular
True or False: Hyaluronan stays in the joint for about 2-3 days.
FALSE: Hyaluronan leaves the joint completely within 24 hours.
Hyaluronan has no effect on ___ progression or ____ in canine stifles.
Hyaluronan has no effect on OA progression or LOADING in the canine stifle.
What are the 5 guidelines for NSAID use?
- Never use an NSAID and steroid together
- Check liver and kidney function prior to use
- D not use more than one NSAID at a time
- Use the lowest effective dose
- Run periodical bloodwork on chronic users
What are the 2 reasons why cartilage generally heals poorly?
- Poor blood supply
2. Chrondrocytes do not multiply in the adult
Micropicking can be used to encourage the formation of what?
Fibrocartilage