Physiology of cartilage

Question 1

what re the 3 main types of cartilage?

Answer 1

Articular/hyaline
Fibrocartilage
Elastic

Question 2

What are the 2 divisions of articular cartilage and where are they found?

Answer 2

Skeletal - articular, costal, growth plate

Extra-skeletal - trachea, larynx, nose

Question 3

Where is elastic cartilage found?

Answer 3

epiglottis

Ear

Question 4

where is fibrocartilage found?

Answer 4

Meniscus

Intervertebral disc

Question 5

What is the function of articular cartilage?

Answer 5

Provide a smooth lubricated surface for articulation

Facilitate load transmission and low friction movement

Question 6

What are the 2 main components of cartilage? what proportions do they exist in?

Answer 6

Cells (5%)

ECM (95%)

Question 7

What is part of the cellular component of cartilage? what is their function?

Answer 7

chondrocytes - synthesise and maintain the ECM

Question 8

What are the components of the extracellular component of cartilage?

Answer 8

Water (70%)
Organic (30%) - mainly type 2 collagen, proteoglycans, hyaluronic acid chains with links contains chondroitin and keratin sulphate

Question 9

What are the layers of articular cartilage on bone?

Answer 9

Articular cartilage
Subchondral bone
Cancellous bone

Question 10

What is necessary for cartilage to heal?

Answer 10

Penetration of subchondral bone for access to blood supply

Question 11

What does cartilage homeostasis depend on?

Answer 11

Balance between synthesis and degradation of cartilage

Question 12

What molecules are needed for degradation of cartilage ?

Answer 12

MMPs:
collagenase
aggrecanase
gelatinases
stromelysins

Question 13

What molecules are needed for synthesis of cartilage ?

Answer 13

collagen
proteoglycans
proteins

Question 14

name methods used for diagnosis of cartilage injuries

Answer 14

X-ray
MRI
Arthroscopy

Question 15

Describe the non-surgical management of cartilage injuries

Answer 15

Physiotherapy
Paracetamol
NSAIDs
Alternative medication: glucosamine and chondroitin sulphate (no evidence but patients claim they work)
Viscosupplementation (no evidence to show it works)
Steroid injection

Question 16

wHy are steroid injections only a short term solution

Answer 16

they ultimately kill chondrocytes

Question 17

What’d does viscosuplementation involve?

Answer 17

Injecting synthetic synovial fluid into the joint

Question 18

List the surgical management of cartilage injuries

Answer 18

Arthroscopy: to perform micro fracturing
Cartilage transplant
Joint replacement

Question 19

Describe the use of arthroscopy as a treatment

Answer 19

TO perform micro-fracturing

Used in small cartilage defects in younger patients to break the subchondral bone to allow cartilage healing.

Question 20

Describe the use of cartilage transplantation as a treatment

Answer 20

Cartilage taken from non-weight bearing portion, performed in people under the age of 30 with small defects

Question 21

Describe the use of joint replacement surgery as a treatment. What objective does it achieve?

Answer 21

cartilage removed and replaced with synthetic material

Relieves pain and increases range of motion