Biomechanics and MS Phys Flashcards
What is Wolff’s Law
Tissues adapt to the forces applied to them
What must be considered for a patient to return to function?
How can we get them to use the leg immediately
Balancing enticing to use limb vs protecting underlying condition
What is important about fracture repair
Early weight bearing is necessary for return to function
What are the components of the joint?
Joint capsule
Synovial fluid
Articular cartilage
Subchondral bone
What are the sections and functions of the joint capsule?
Outer fibrous: mechanical support, originates from periosteum - Sensitive to pain or stretching to joint
Inner Synovial: composed of synoviocytes - needed for phagocytosis, hyaluoronic acid production
What is synovial fluid composed of?
Plasma ultrafiltrate and hyaluronic acid
Where does cartilage receive its nutrition
Synovial fluid - has no blood or lymph supply
What are the functions of synovial fluid?
- Supports articular cartilage
- removes metabolic waste
- Lubricates joint - inflammation leads to decreased viscosity - decreased lubrication
What factors are necessary for joint nutrition and waste removal?
Weight bearing and joint motion
What are the function of chondrocytes in articular cartilage
Produce proteoglycans (needed for compressive strength
What is the function of collagen in articular cartilage
Produces tensile strength
What is the function of articular cartilage
Absorb shock
- Has lots of water
Why is cartilage bad at healing
- Lots of water
- No blood or lymph supply
What is subchondral bone and what is its function?
- Absorb and distribute forces
- Decrease load on cartilage
What law of physics is important for returning to function
Force = mass x acceleration
What are factors that destroy cartilage?
High impact loading - abnormal forces on a normal joint
High contact pressures: normal forces on an abnormal joint
What are examples of an abnormal joint?
- Injury to joint or surrounding tissues
- Surgical alterations to joint (e.g TPLO)
What are examples of abnormal pressures to a normal joint?
Overuse and high impact secondary to sport
How can forces be decreased to a joint?
Decrease mass (weight loss vs UW treadmill)
Low impact training (derease acceleration)
- Minimize inflammation during initial acute inflammation
What are side-effects of immobilizing jionts
- Proliferation of adhesion
- Cartilage atrophy
- Decreased proteoglycan and collagen
- Decreased synovial fluid
How should mobilization, be reintroduced to limb after being imobilized?
Slow and gradual
- High intensity exercises damage limb
What effects do continued high impact have on joints?
Decreased PG synthesis
SC bone sclerosis
Damage to cartilage
What are the benefits to long-term low-impact cartilage
- Maintains joint health
- Low-impact activity does not degenerate joint in long-term
What is osteoarthritis
Irreversible articular cartilage degeneration, fibrillation, erosion
