Cartilage injuries and arthritis

Question 1

Where is hyaline cartilage found?

Answer 1

Covering the surface of bones at synovial joints

Question 2

What are the functions of hyaline cartilage?

Answer 2

Decrease friction

Distribute load

Question 3

Describe the structure of hyaline cartilage

Answer 3

Water
Collage type II
Proteoglycans
Chondrocytes

Question 4

What do chondocytes do?

Answer 4

Produce collagen (type II), proteoglycans and enzymes which help maintain the extracellular matrix

Question 5

How does hyaline cartilage receive it’s nutrition?

Answer 5

Synovial fluid

Subchondral bone

Question 6

What is the function of proteoglycans?

Answer 6

Highly hydrophilic molecules which “inflate like balloons” to provide compressive strength

Question 7

What is the function of collagen?

Answer 7

Tensile strength

Question 8

What are proteoglycans made of?

Answer 8

Hyaluronic acid

Question 9

Hyaline cartilage defects can be traumatic or atraumatic. Give some examples of both

Answer 9

Traumatic 
 - Ligament injury
 - Dislocation
Atraumatic 
 - Osteochondritis dissecans 
 - Osteoarthritis 
 - Inflammatory arthritis

Question 10

Which type of cartilage injuries heal? What is different about healed cartilage as compared to normal cartilage?

Answer 10

Full thickness

Not hyaline but fibrocartilage which is less wear resistant with greater friction

Question 11

What is osteochondritis dissecans?

Answer 11

Area of the knee loses its blood supply and cartilage +/- bone fragment detachment

Question 12

In what age group is osteochondritis dissecans most common?

Answer 12

Adolescents

Question 13

How is osteochondritis dissecans managed?

Answer 13

May heal/resolve spontaneously
Can pin in place if detaching on MRI
Can fix or remove if detached
Cartilage regeneration in severe cases

Question 14

Is cartilage regeneration more effective on big or small defects?

Answer 14

Small

Question 15

Which joint can cartilage regeneration techniques NOT be performed on? Why?

Answer 15

Patellofemoral joint

There is too much sheer stress at this joint for it to be effective

Question 16

What are the techniques used for cartilage regeneration?

Answer 16

Drilling/microfracture
Mosaicoplasty
MACI
Osteochondral auto/allograft

Question 17

What does MACI stand for?

Answer 17

Membrane induced autologous chondrocyte implantation

Question 18

What are the contra-indications to cartilage regeneration?

Answer 18

Radiographic signs of osteoarthritis
Joint instability
Inflammatory arthritis

Question 19

Why are open procedures not great with respect to cartilage regeneration?

Answer 19

Air is toxic to hyaline cartilage

Question 20

What techniques of cartilage regeneration are used in tayside and why?

Answer 20

Microfracture - cheap and easy

Allograft - larger defects +/- bone damage

Question 21

What is osteoarthritis?

Answer 21

Pathology of the joints resulting from imbalance of cartilage breakdown and regeneration

Question 22

What predisposes to osteoarthritis?

Answer 22

Injury
Malalignment
Degenerate meniscal tear
Infection
Genetic

Question 23

How is osteoarthritis initially managed?

Answer 23

Weight loss
Analgesia
Activity modification, aids, etc

Question 24

When are steroid injections indicated in osteoarthritis?

Answer 24

Acute flare ups

Question 25

What are the risks of steroid injection with respect to osteoarthritis?

Answer 25

Too many injections can accelerate OA | Infection risk

Question 26

When is osteotomy indicated in osteoarthritis?

Answer 26

Early medial compartment OA in a varus leg

Question 27

When is debridement and washout indicated in osteoarthritis?

Answer 27

Never because it doesn't work

Question 28

Which compartment of the knee will be under the most stress in a varus and valgus knee respectively?

Answer 28

Varus - medial | Valgus - lateral

Question 29

How can the directions of the legs in genu varum and valgus be remembered?

Answer 29

VaRum - feet Return | VaLgus - feet Leave

Question 30

When is knee replacement indicated for osteoarthritis? Which type of knee replacement is most effective?

Answer 30

Elderly patients with end stage disease. | Total replacement has better results than partial replacement

Question 31

What are the risks of knee replacement?

Answer 31

Deep infection Stiffness Pain DVT +/- PE