cartilage

Question 1

What is hyaline cartilage?

Answer 1

1. most common cartilage
2. found on most non-articular surfaces such as the ends of ribs, nasal septum, lyarx, tracheal ring
3. collage fibers are cross linked and loosely woven together

Question 2

Where do you find elastic cartilage and how is it treated?

Answer 2

1. not typically treated by PT

2. found in the exteranl ear, auditory canals, epiglottis, laryngeal cartilage, and walls of eustachian tubes

Question 3

which is more dense elastic or hyaline cartilage

Answer 3

elastic

Question 4

How is Fibrocartilage organized?

Answer 4

consists of alternating layers of hyaline cartilage and dense collagen fibers orientd in a directions of stress

Question 5

Where do you typically find fibrocartilage?

Answer 5

intervertebral discs, articular cartilage, pubic symphysis, capsules, ligaments, enthesis

Question 6

What is the functional cell of cartilage?

Answer 6

Chondrocytes

Question 7

What is the root function of chonrocytes?

Answer 7

1. produce and control ECM

2. immature chondrocytes know as chondroblasts produce GAG and type II collagen

Question 8

What are the metabolic properties of cartilage?

Answer 8

1. by nature cartilage is devoid of nerve supply, blood vessels and lymphatic vessels
2. anaerobic metabolism is used by cartilage in its low oxygen environment

Question 9

How does cartilage have both solid and flexible properties?

Answer 9

the ground substance of glycoprotiens imbibies water giving it viscoelastic properties

Question 10

What is cartilage made of?

Answer 10

1. half the dry weight is type II collagen

2. proteoglycans make up about 4-7% of the ECM

Question 11

What are proteoglycans?

Answer 11

complex macromolecules comprised of a protein core joined to a long non-branching polysaccride such as GAG

Question 12

How does cartilage resist high tensile loads?

Answer 12

since it is made of 65-80% water it is essentially noncompressable and is able to take high tensile loads

Question 13

What are the layers of articular cartilage?

Answer 13

1. superfiscial
2. middle
3. deep
4. calcified

Question 14

What is the superficial layer of articular cartilage?

Answer 14

1. collagen in oriented parallel to joint surface
2. rich in collagen
3. low in proteoglycans
4. high in tensile loads

Question 15

What is the middle layer of articular cartilage?

Answer 15

1. less organized collagen

2. greater proteoglycan content than the superficial layer

Question 16

What is the deep layer of articular cartilage?

Answer 16

1. highest concentration of proteoglycans
2. collagen organized to resist shear
3. compression improves in capacity for resisting shear

Question 17

What is the calcified zone of articular cartilage?

Answer 17

1. large content of apatite salt
2. minimal blood supply
3. transports nutrients to other layers

Question 18

How is the metabolic rate of collagen regulated?

Answer 18

1. hydrostatic pressures
2. growth factor
3. interleukins
4. matrix make up
5. electric fields

Question 19

How is fluid imbibed into cartilage?

Answer 19

1donnan osmotic pressure- differences in intra and extra cellar ionic charge creates a magnetic effect

2. electroastic repulsion forces- proteglycans have a negative charge creating metabolic movement
3. entropic tendency of proteoglycans to gain volume

Question 20

How are proteteoglycans produced?

Answer 20

1. compression of cartilage triggers production
2. the rough endoplasmic reticulum produces a protein core
3. as the protein core leaves the RIR it is sulfated by the Golgi apparatus
4. the sulfated protien core passes through the membrane and attaches to hylauronic acid

Question 21

How does compression benefit from cartilage?

Answer 21

1. triggers production of GAG

2. increase rate solutes move towards and away from cells deep within cartilage

Question 22

How does joint gliding benefit cartilage?

Answer 22

gliding causes the synovial fluid to become less viscous which facilitates imbibition of the cartilage

Question 23

How do you decrease synovial fluid viscosity?

Answer 23

1. joint gliding

2. the fast the movement the less viscose the synovial fluid

Question 24

What characteristic of cartilage allows it to manage the high reps?

Answer 24

It has biphasic properties

1. sold under compressions
2. fluid for nutrient exchange

Question 25

How is nutrition and wast removal regulated by cartilage?

Answer 25

the chondrosynovial membrane 1. a thing permeable membrane covering the surface of cartilage 2. prevents rapid fluid exudation under loading

Question 26

What is the optimal stimulus for repair of collagen?

Answer 26

compression decompression with gliding 1. compression/decompression stimulates chondroblast and increased nutrient exchange 2. gliding decreases synovial fluid viscosity

Question 27

What is the only non-blast cell to produce collagen

Answer 27

chondrocyte

Question 28

What joint in the body does not receive cartilage OSR with gravitational loading?

Answer 28

Lumbar spine due to the orientation of the facets 1. rotation- creates contralateral facet opposition 2. flex and provide gliding

Question 29

How do you provide facet cartilage OSR?

Answer 29

1. compression/decompression via rotation | 2. gliding- flexion and extension

Question 30

What are some intrajoint mechanical structures that help attenuate force?

Answer 30

1.fat pads that move in and out of the joint such as infrapetellar, pulvinar acetabulum and facet

Question 31

How does hyaline cartilage change when it heals?

Answer 31

it is usually replaced by fibrocartilage which has poor mechanical properties

Question 32

How does immobilization impact muscle?

Answer 32

immobilization in a shorted position causes 40% loss of sacrcomers and in a lengthened position causes a 20% gain

Question 33

How does recovery time after immobilization and damage during immobilization compare?

Answer 33

1. the damage occurs on an exponential rate | 2. recovery occurs on a linear rate

Question 34

What is the pattern of collagen loss with immobilization

Answer 34

1. 9 weeks 14% loss with a 2 % loss 2. 12 weeks 28% loss with a 27% net loss 3. in other words you have an exponential loss

Question 35

Describe the healing process following a cartilage injury through to the subcondral bone

Answer 35

1. cells travel through subcondral vessels to initiate the healing process 2. fibrin clot forms a framework from mesenchymal cells from the marrow to produce a fibrocartilagenous base 3. growth factor such as platelet derived GF and transforming GF beta can attract undifferentiated cells to the fibrin clot

Question 36

What extrinsic variable effects cartilage permeability the most?

Answer 36

1. rate of loading due to the viscoelastic properties 2. fast loading has less fluid movement 3. prolonged or slowly applied loads move fluids best

Question 37

Describe the repair process of a superficial laceration of the cartilage?

Answer 37

There isn't one because there is no vascularization

Question 38

How does immobilization effect cartilage enzyme function?

Answer 38

1. lactic dehydrongenase and malic dehydrogense decrease so you have less production 2. lysosomal hydrolase increase activity degrading GAG

Question 39

How does immobilization effect cellular alignment?

Answer 39

distorts alignment and you lose mechanical tensile properties

Question 40

How does immobilization effect collagen bundle width?

Answer 40

1. decreases it via loss of total number of bundles 2. 14% at 9 weeks 3. 38% at 12 weeks

Question 41

How does immobilization effect muscles?

Answer 41

1. weakening of boney insersion 2. decreased muscle belly circumfrence 3. decreased extensibility 4. muscle fiber atrophy (slow>fast) 5. either a loss or gain of sarcomes depending on the position

Question 42

What does type III collagen usually show up first at an injury site (2 reasons)?

Answer 42

1. it has the ability to rapidly form cross links to establish an early fragile stability at the repair site 2. cell that normally produce type I collagen produce type III at the time of injury

Question 43

What did Salter's study in 1980 demonstrate about cartilage?

Answer 43

CPM helps with heeling.

Question 44

Why is cartilage healing difficult?

Answer 44

cartilage is avasuclar , anueral, alympathic and has a low metabolic rate

Question 45

How come rehabing healed articular cartilage is difficult?

Answer 45

Repaired articular cartilage is usually type III collagen 1. it lacks cross bonding of normal cartilage 2. leads to weakness and tendency for repair site to swell more than surrounding tissue 3. more susceptible to damage because gaps form in the tissue and it has a reduced quality of matrix

Question 46

What general dosing is used for cartilage exercises?

Answer 46

1. very high reps 2. low resistance starting NWB 3. restore joint mobility 4. restore muscle tone and balance 5. endurance 6. strength 7. motor control

Question 47

How does over stressing articular cartilage effect its properties?

Answer 47

1. articular cartilage become stiffer 2. decreased ability to attenuate force across a greater area 3. focal points of impact can lead to sclerotic changes 4. leads to diminished nutrient flow from subcondral bone

Question 48

What nutritional supplements benefit cartilage?

Answer 48

1. 1.5 g Glucosamine | 2. 2g day Omega 3

Question 49

A change in varus knee position of 4-6 degree can change the internal knee pressures by how much?

Answer 49

1.medial compartment loading 70-90%

Question 50

How does NSAID work?

Answer 50

inhibits cyclo-oxygenase enzyme in the synthesis of prostiglandins from arachondonic acid

Question 51

How do NSAIDs negatively effect joint healing?

Answer 51

1. inhibit the production of proteoglycans 2. impaired protein synthesis 3. the inflammatory process produces cytokines interlukin that clear the broken down

Question 52

How does a menisectomy impact effect knee joint cartilage?

Answer 52

1. it disrupts normal normal anabolic and catabolic processes 2. also signs of degenerative cartilage loss

Question 53

How does age impact cartilage regeneration?

Answer 53

1. decreased capacity of chondrocytes to link protein 2. decreased rate of histological events 3. decreased energy stores so dosing considerations must be made 4. calcification of subchondral bone decreasing nutrient exchange increasing the importance of imbibition

Question 54

What is the optimal stimulus for chondrocytes to produce cartilage?

Answer 54

1. compression 2. decompression 3. shearing

Question 55

Hoe are progenitor cells used in tissue repair?

Answer 55

1.osteochondral progenitor cells can be grown in vitro from autologeus bone marrow and transplanted surgically to trigger conventail repair of cartilate

Question 56

What is a periosteal graft?

Answer 56

periosteal or periochondral tissue is harvested from a remote site and implanted in other joints

Question 57

Why should pain be avoided with exercise?

Answer 57

1. its a signal of excessive tissue deformity 2. chronic inflammation produces more scar tissue 3. pain alters normal circulation via sympathetic response 4. muscle recruitment patterns are altered

Question 58

How will exceeded the tolerance of cartilage present clinically?

Answer 58

1. cartilage is not innervated so it will not have a pain response 2. secondary edema within 24 hours 3. loss of ROM