Normal fracture healing

Question 1

What are the stages of bone healing?

Answer 1

• 3 stages
• Reactive, reparative, remodelling
• Reactive and reparative have 2 parts

Question 2

Describe the reactive phase of bone healing?

Answer 2

• Occurs within 48 hours of injury
• 2 parts: haematoma and inflammation
• Haematoma: bleeding into fracture site and necrosis of bone ends
• Inflammatory: haematoma invaded by osteoclasts and macrophages which remove dead and damaged tissue

Question 3

What are the 2 parts of the reparative stage of bone healing?

Answer 3

Proliferation and consolidation

Question 4

Describe the proliferation phase (reparative stage) of bone healing?

Answer 4

• Occurs after 2 weeks
• Osteoblasts produce osteoid tissue which creates a firm mass/callus around the fracture

Question 5

Describe the consolidation phase (reparative stage) of bone healing?

Answer 5

• Occurs after 4-6 weeks
• Endochondral ossification occurs, leading to woven bone formation
• Bone regains some mechanical strength

Question 6

Describe the remodelling stage of bone healing?

Answer 6

• Turning woven bon into lamellar bone
• Can take months to years
• Doesn’t always happen fully, which increases future risks of OA