Fracture healing

Question 1

Describe the three main steps by which a fracture is likely to heal normally & for each step describe the normal cellular response

Answer 1

Will heal by secondary healing

Main cytokines- TGF-B, FGF, BMP

Inflammatory phase:

• bleeding from torn vessels
• clotting cascade activated & inflammatory cells (platelets, macrophages) move to site of fracture,
• haematoma forms in fracture gap
• occurs immediate from injury.

Reparative phase:

• Mesenchymal stem cells become fibroblasts, osteoblasts and chondroblasts at the fractures site
• callus formed by intramembranous ossification at cortical bone ends (hard callus) & by chondrogensis at periphery (soft callus)-
• starts w/in first few days & lasts few weeks

Remodelling phase:

• Wowen bone replace by lamella bone
• excess callus reabsorbed
• Begins few weeks after injury & lasts years

Question 2

Risk factors that can delay fracture healing?

Answer 2

Diabetes

Smoking

Question 3

What are systemic complications associated w/ bone fractures or damage to soft tissues

Answer 3

Shock syndrome

avascular necrosis

fat emboli- cam cause pulmonary insufficiency

exacerbation of underlying diseases e.g. diabetes