Osteoarthritis

Question 1

When does bone grow

Answer 1

Traction

Not compression

Putting the physis under tension

Question 2

Outline different types of deformity

Answer 2

Hips and ankles still aligned but the nees are not

Varus deformity (bowing- far apart knees and cos together ankles)

Valgus deformity Knock kneed (wider part ankles, close together knees)

Question 3

Who gets varus

Answer 3

Football players (knees far apart and ankles close together)

Question 4

Who gets valgus

Answer 4

Supermodels (ankles far apart and knees very close together)

Question 5

Why does alignement matter

Answer 5

Usually weight goes straight down the leg (normally a bit more through the medial)

In varus people, they get more weight going through the medial compartment

In the valgus people, they get weight going through the lateral side

Question 6

What is the consequence of the malalignment to the joint

Answer 6

Increases risk of osteoarthritis

Becuase there is a loss of joint space on the side bearing more load, and this leads to bone-on-bone articulations

Question 7

What would you do with misalignment people

Answer 7

Osteotomy before the joint cartilage damage occurs

You crank open a part of the knee to a fine degree of accuracy to make the leg straight (i.e. 3.6 degrees on the diagram)

Diagram

Question 8

What is the wollf’s law

Answer 8

The trabecular and the spongey bone adapt to the load

So the bone is oriented in columns parallel to the stress

Question 9

What happens in developmental dysplasia of the hip

Answer 9

That the femur is sitting too high and pushing the acetabuum up, theere is no proper groove in the pelvis for the femur to articulate

Question 10

What happens in DDH

Answer 10

The femur moves up on the acetabulum and the pushes on the labrum (cartilage on the superior aspect of the acetabulum) is worn down a lot leading to OA

Question 11

What is a cam impingements

Answer 11

Bump in the femoral neck

During abduction, there is going to be rubbing between the femoral neck and the acetabulum

Can lead to early OA

More common in MALES (andy murray!)

Question 12

What is a pincer impingement

Answer 12

Extra bone on the acetabulum superiorly

Still pumping in abduction

Question 13

What happens during crashing of the femoral head against acetabulum in cam and pincer impingement

Answer 13

Because this is essentially bone loading when there is contact , then the bone will grow at this point! So the bump will get bigger

Question 14

How can cam or princer cause OA

Answer 14

The bump in the femur (cam) or the acetabular (pincer) then there will be bumping into the labrum and then this will cause OA

Question 15

Role of capsule

Answer 15

To contain the synovial fluid

Question 16

What is the capsule continuous with

Answer 16

The periosteum

Question 17

What is the articular cartilage

Answer 17

This is the part stopping bone rubbing together

Question 18

What is the menisci for

Answer 18

It helps you to distribute the load actross the whole tibial plateau (less point loading, which occurs because there is a rounded femoral surface on a flat tibial surface normally)

Look at the diagram

Question 19

Outline the growth plate

Answer 19

In utero, cartilage laid down that is going to be the shape of the bone

Over time cartilage ossifies to take over bone

Ossification begins 10-11 weeks in utero in the diaphysis

In the physis there are proliferating cartilage cells which move up toward to epiphysis and become bone