Fractures through the Ages

Question 1

Density of bone is greater pre or post birth?

Answer 1

Prebirth

Question 2

At what age does bone start to become ordered and structured?

Answer 2

• In a 1-year-old infant

Question 3

What is the strength of bone dependant on? (2)

Answer 3

The strength of bone is dependent on the amount of tissue, but also the structure

Question 4

What cells detect how bene is being loaded?

Answer 4

Osteocytes

Question 5

Oestrogen effect of osteoclasts/blasts?

Answer 5

Oestrogen brings about osteoclast apoptosis and upregulates osteoblasts

Question 6

Effect of bisphosphonates?

Answer 6

These kill osteoclasts – basically have the same purpose as oestrogen

Question 7

Bisphosphonates with prolonged use cause … and why?

Answer 7

micro-fractures

- This happens because we don’t self-repair small fractures that happen due to everyday activities because of the drugs

Question 8

What is denosumab? How does it work?

Answer 8

enosumab is a monoclonal antibody which mimics osteoprotegerin – this binds preferentially to RANKL molecules on osteoblasts, prevents them reaching osteoclasts and prevents osteoclast upregulation

Question 9

What can mimic osteoprotegerin

Answer 9

denosumab

Question 10

What does denosumab mimic

Answer 10

Osteoprotegerin

Question 11

What does osteopretegrin do

Answer 11

this binds preferentially to RANKL molecules on osteoblasts, prevents them reaching osteoclasts and prevents osteoclast upregulation

Question 12

Hip fracture mortality:

At 30 days?

At 1 year?

Answer 12

12% then 20%

Question 13

When is peak bone mass?

Answer 13

• Peak bone mass is somewhere in the late teenage years

Question 14

What is essential for good bone health and to reach peak bone mass?

Answer 14

• Good diet and exercise is essential for reach peak bone mass
• Vitamin D and calcium regulation are also essential for good bone health

Question 15

What is stage 1 of bone healing and how long does it last?

Answer 15

Up to 1 week:

 Haematoma and inflammation stage

Question 16

What is stage 2 of bone healing and how long does it last?

Answer 16

1-4 weeks:

 Soft callus stage:

Question 17

What is stage 3 of bone healing and how long does it last?

Answer 17

– 1-4 months:

 Hard callus stage

Question 18

how long does stage 4 of bone healing last?

Answer 18

Up to several years

Question 19

What happens in stage 1 of bone healing?

Answer 19

 Haematoma and inflammation stage:

• Macrophages, leukocytes, IL1-6, BMPs etc.
• Granulation tissue forms
• Progenitor cells invade

Question 20

What happens in stage 2 of bone healing?

Answer 20

 Soft callus stage:

• Chondroblasts and fibroblasts differentiate and form collagen II and fibrous tissue
• Proteoglycans produced – prevent mineralization
• Chondrocytes release calcium into ECM and degrading enzymes to break down proteoglycans – allows mineralization

Question 21

What happens in stage 3 of bone healing?

Answer 21

 Hard callus stage:

• Soft callus invaded by blood vessels
• Chondroblasts break down calcified callus
• Replaced by osteoid (type I collagen) from osteoblasts
• Osteoid calcifies – woven bone

Question 22

What happens in stage 4 of bone healing?

Answer 22

 Remodeling
 Woven to lamellar bone
 Shape relative to stresses (Wolff’s law)
 Medullary canal reforms

Question 23

4 fracture patterns and when do they happen?

Answer 23

Spiral – Happens with arm wrestling etc.
Oblique – Blunt trauma to the bone (crush injury)
Comminuted – Blunt trauma where the force that caused the trauma continues even after the initial impact (causes butterfly fragments)
Transverse – Direct force through bone which is then immediately removed

Question 24

What is greenstick fracture? When is it common and why?

Answer 24

– Bone has been bent and caused an incomplete fracture These are much more common in paediatrics as children have a thick periosteum
- If a child has a completely snapped bone rather than a greenstick fracture, then suspect child abuse – ask them how the child did it

Question 25

A fracture in a child rather than a greenstick is a red flag for what?

Answer 25

Child abuse

Question 26

What is a red flag for child abuse

Answer 26

A fracture in a child rather than a greenstick

Question 27

When does a oblique fracture happen?

Answer 27

Blunt trauma to the bone (crush injury)

Question 28

When does a comminuted fracture happen?

Answer 28

Blunt trauma where the force that caused the trauma continues even after the initial impact (causes butterfly fragments)

Question 29

When does a transverse fracture happen?

Answer 29

Direct force through bone which is then immediately removed

Question 30

When does a spiral fracture happen?

Answer 30

Happens with arm wrestling etc.