Bone growth and fracture healing Flashcards
What is a fracture?
A break in structural continuity of bone - may be a crack, break, split, crumpling, buckle
What is the shorthand sign for a fracture?
#
What can lead to bones failing?
High energy transfer in normal bones
Low energy transfer in abnormal bones
Repetitive stress in normal bones
What abnormalities can reduce the threshold for energy transfer in bones?
Osteoperosis
Osteomalacia
Metastatic tumour
etc
What are the 4 stages of fracture repair?
Inflammation
Soft callus
Hard callus
Bone remodelling
When does inflammation begin?
Immediately after fracture
What happens in inflammation?
Haematoma and fibrin clot
Platelets, neutrophils, macrophages, etc
Osteoprogenitor cell activity
Angiogenesis
What are osteoprogenitor cells and what do they do?
They are transformed endothelial cells from the medullary canal or periosteum
They are osteogenic inductors of muscle and soft tissue cells
What is required for angiogenesis?
Oxygen gradient - low
Macrophages
When does the soft callus stage begin?
When pain and swelling subside
When does the soft callus stage last until?
Bony fragments are united by cartilage or fibrous tissue
What is the purpose of the soft callus stage?
Gives fracture some stability
Angulation can still occur
Continued increase in vascularity
What is the hard callus stage?
Conversion of cartilage to woven bone
What is the bone remodelling stage?
Conversion of woven bone to lamellar bone with reconstruction of medullary canal
How is instability of a fracture expressed?
Magnitude of strain