Fractures through the Ages Flashcards
Density of bone is greater pre or post birth?
Prebirth
At what age does bone start to become ordered and structured?
- In a 1-year-old infant
What is the strength of bone dependant on? (2)
The strength of bone is dependent on the amount of tissue, but also the structure
What cells detect how bene is being loaded?
Osteocytes
Oestrogen effect of osteoclasts/blasts?
Oestrogen brings about osteoclast apoptosis and upregulates osteoblasts
Effect of bisphosphonates?
These kill osteoclasts – basically have the same purpose as oestrogen
Bisphosphonates with prolonged use cause … and why?
micro-fractures
- This happens because we don’t self-repair small fractures that happen due to everyday activities because of the drugs
What is denosumab? How does it work?
enosumab is a monoclonal antibody which mimics osteoprotegerin – this binds preferentially to RANKL molecules on osteoblasts, prevents them reaching osteoclasts and prevents osteoclast upregulation
What can mimic osteoprotegerin
denosumab
What does denosumab mimic
Osteoprotegerin
What does osteopretegrin do
this binds preferentially to RANKL molecules on osteoblasts, prevents them reaching osteoclasts and prevents osteoclast upregulation
Hip fracture mortality:
At 30 days?
At 1 year?
12% then 20%
When is peak bone mass?
- Peak bone mass is somewhere in the late teenage years
What is essential for good bone health and to reach peak bone mass?
- Good diet and exercise is essential for reach peak bone mass
- Vitamin D and calcium regulation are also essential for good bone health
What is stage 1 of bone healing and how long does it last?
Up to 1 week:
Haematoma and inflammation stage
What is stage 2 of bone healing and how long does it last?
1-4 weeks:
Soft callus stage:
What is stage 3 of bone healing and how long does it last?
– 1-4 months:
Hard callus stage
how long does stage 4 of bone healing last?
Up to several years
What happens in stage 1 of bone healing?
Haematoma and inflammation stage:
- Macrophages, leukocytes, IL1-6, BMPs etc.
- Granulation tissue forms
- Progenitor cells invade
What happens in stage 2 of bone healing?
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
What happens in stage 3 of bone healing?
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
What happens in stage 4 of bone healing?
Remodeling
Woven to lamellar bone
Shape relative to stresses (Wolff’s law)
Medullary canal reforms
4 fracture patterns and when do they happen?
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
What is greenstick fracture? When is it common and why?
– 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
A fracture in a child rather than a greenstick is a red flag for what?
Child abuse
What is a red flag for child abuse
A fracture in a child rather than a greenstick
When does a oblique fracture happen?
Blunt trauma to the bone (crush injury)
When does a comminuted fracture happen?
Blunt trauma where the force that caused the trauma continues even after the initial impact (causes butterfly fragments)
When does a transverse fracture happen?
Direct force through bone which is then immediately removed
When does a spiral fracture happen?
Happens with arm wrestling etc.
