cartilage injuries and knee arthritis

Question 1

Where is hyaline cartliage found ?

Answer 1

On the surface of bone in synovial joints

Question 2

What is the function of hyaline cartilage

Answer 2

to decrease friction and distribute load

Question 3

What is hyaline cartilage composed of and where does it get its nutrition from ?

Answer 3

• Comprised of water, collagen, protyeoglycans & chondrocytes.
• Gets its nutrition from synoival fluid and subchondral bone

Question 4

What is the function of chondrocytes

Answer 4

They produce collagen, PGs & enzymes to regulate the ECM

Question 5

What do proteogylcans contribute to hyaline cartilage ?

Answer 5

Proteoglycans highly hydrophillic à act like balloons to give compressive strength

Question 6

What does the presence of collagen provide to hyaline cartilage ?

Answer 6

Collagen fibres give tensile strength

Question 7

What is this structure ?

Answer 7

Proteoglycan

Question 8

When hyaline cartilage heals what does it heal as ?

Answer 8

Healing is with fibrocartilage which has greater friction and is less wear resistant

Question 9

What is Osteochondritis Dissecans?

Answer 9

An area of the surface of the knee loses its blood supply and cartilage +/- bone can fragment off

Question 10

What can be done to treat osteochondritis dissecans ?

Answer 10

• If detaching on MRI can pin in place
• If detached can fix or remove
• Can heal or resolve spontaneously
• If severe patient may benefit from cartilage regeneration techniques

Question 11

Who is osteochondritis dissecans more common in ?

Answer 11

Adolescence

Question 12

If the patient had severe osteochondritis dissecans and you were considering cartilage rengeration what would stop you from going ahead with it ?

Answer 12

Not if radiographic changes OA, inflammatory arthritis, joint instability

Question 13

What are the 4 main different options for cartilage rengeration?

Answer 13

1. Drilling / microfracture
2. Osteochondral autograft or allograft
3. Mosaicplasty
4. MACI – membrane induced autologous chondrocyte implantation

Question 14

What is OA?

Answer 14

An Imbalance of cartilage breakdown and repair

Question 15

List some of the factors which predispose patients to developing OA?

Answer 15

• Injury - e.g. fracture, joint instability, articular cartilage injury
• Malalignment - e.g. genu varum
• Degernate meniscal tear
• Infection
• Also familial / genetic influences

Question 16

What are some of the non-operative treatments for OA ?

Answer 16

• Weight loss, stick, exercise, analgesics, activity modification
• Steroid injection only for acute flare-ups

Question 17

What are the operative treatment options for early OA?

Answer 17

• No easy solution
• Very limited options

Osteotomy can be useful in varus knee with isolated early medial compartment OA

Question 18

When are knee replacements done ?

Answer 18

Only for older patients with end stage arthritis

Question 19

If put in well how long would you expect a Total knee replacement (TKR) to last?

Answer 19

15-20 years