Bone healing and fracture management

Question 1

What are the 3 phases of the bone healing process?

Answer 1

1. Inflammatory phase
2. Restoration phase
3. Remodelling phase

Question 2

What happens in the inflammatory phase of bone healing?

Answer 2

• There is lysis of osteocytes and cells of the dead soft tissues → liberation of substances in the fracture site that attract inflammatory cells and macrophages
• A blood clot forms at the site within a couple of injuries
• Phagocytes clean the site of the fracture

Question 3

What happens during the restorative phase of bone healing?

Answer 3

• The soft callus forms
• Although elastic, the callus starts to stabilise the fracture site
• This phase can last 4 days-3 weeks
• As the fracture is stabilised and blood supply restored, the newly formed cartilage is progressively substituted by bone tissue (endochondral ossification)
• This results in the formation of the hard callus (6-12 weeks after injury)
• Relies on a stable fracture site; harder to achieve if movement occurs

Question 4

Describe the remodelling phase of bone healing

Answer 4

• The callus envelops the fracture site - similar to scars on skin
• Remodelling involves osteoclasts
• Can take months-years

Question 5

Describe the difference between first intention and second intention bone healing

Answer 5

• First intention: minimal bone callus formation. Can be seen when we repair a fracture surgically. Ossification is faster than by second intention.
• Second intention: most common natural type of healing. Happens with late healing/poor blood supply/loss of fragments/infection/absent forces of compression