Pathophysiology of Osteoarthritis Flashcards
What is the definition of Osteoarthritis?
A heterogenous group of conditions that lead to joint symptoms and signs which are associated with defective integrity of articular cartilage, in addition to related changes in the underlying bones at the joint margins
In Osteoarthritis what can be observed?
- Cartilage is lost
- Imbalance of degradation and repair
- All joints are NOT affected equally
What is the most common form of arthritis?
OA
What is a major cause of long term disability?
QA
What are the systemic factors that are affected by OA?
Makes cartilage more vulnerable to repeated injury, it is less capable of repair
What are factors influencing susceptibility to OA?
- Age
- Sex
- Genetics
- Obesity
- Occupation
- Sports
Prevalence and Severity of disease increases with what?
Age
What are the possible mechanisms of increased OA with aging?
- Reduced repair
- Ligament laxity
- Muscle weakness
- Neurologic slowing
- Reduced non-calcified
Which sex has a higher risk of OA age below 45?
Males
Which sex has a higher risk of OA age above 55?
Female
Which sex has a higher risk of OA in the hands and knees?
Women
If your parents had OA, what is your risk for OA?
HIGHER and EARLIER
Is obesity a modifiable risk factor?
YES
With increased weight what increases?
Increased knee OA and increased risk
How is occupation a risk factor of OA?
Repetitive trauma, overuse, and overloading
What types of sports lead to OA?
Sport injuries, high intensity, direct impact, and repetitive impact
Does recreational running lead to OA?
Not really, unless they are already predisposed to OA where running could add additional stress
What is Primary OA?
Idiopathic
What is Secondary OA?
Identifiable cause Present
What is Generalized OA?
At least 3 local sites involved
What are the local sites?
- Hands
- Feet
- Knees
- Hips
- Spine
- Shoulder
What is Localized OA?
1 site
What is DISH?
Diffuse Idiopathic Skeletal Hyperostosis: large, numerous osteophytes, affect the spine
What is Normal Articular Cartilage?
Thin, vascular, neural covering of bone in joints
What is Normal Articular Cartilage composed of?
- Water
- Type II Collagen
- Proteoglycans
What does collagen do?
Provide structure, strength, and shape
What are proteoglycans?
Protein cores with linked disaccharides
What do glycosaminoglycans do?
Draw in water, restricted by collagen
What does cartilage do?
Provide resilience, elasticity, and lubrication to joint
What do chrondrocytes do?
Control synthesis and degradation
What is obtained from synovial fluid?
Nutrients
Eventually, underlying bone is revealed leading to reactive bone changes, causing what pathologic changes?
- Irregular thickening, sclerosis and remodeling of bone
- Cysts in bone underlying cartilage
- Marginal osteophyte formation
What is seen in EARLY OA?
Decrease extracellular matrix, Increase water
What is changes are seen in OA?
DECREASE chondrocytes and proteoglycan
What happens to the degraded proteoglycans?
They are released into synovial fluid causing inflammatory response
New bone growth at joint margins is classified as what?
Osteophytes
What causes would classify Secondary OA?
- Trauma
- Abnormal joint stresses or mechanics
- Genetic abnormalities of the cartilage
- Metabolic or endocrine abnormalities
- Crystal deposition
- Inflammatory conditions of joints
- Avascular necrosis
- Neuropathic
What are the clinical symptoms of OA?
- Joint pain
- Stiffness with inactivity
What is joint pain described as in OA?
Use related, later also at rest or night pain
What is stiffness with inactivity described as in OA?
Gelling, short duration
What joints are at the Highest Risk of OA?
- Distal and Proximal Interphalangeal Joints
- 1st Carpometacarpal Joint
What are the clinical signs of OA?
- Enlargement and Deformity
- Coarse crepitus
- No clinical signs of inflammation
- Restricted painful movements decreased range of motion
- Instability
What are the forms of enlargement and deformity?
- Heberden Nodes DIP Nodules
- Bouchard Nodes PIP Nodules
What is a main X-Ray finding in OA?
Joint space narrowing due to cartilage loss