THIS SLIDE DEALS WITH THE HEALING OF THE BONE AND THE STAGES OF THE Healing explained

1. Principles of
Fracture Healing

2. Principles of Fracture Healing
• Diaphysis
• Shaft of a long bone
• Epiphysis
• Ends of the bone
• Metaphysis
• Area between the diaphysis and epiphyses
• Hyaline cartilage
• Found at the ends of the bone
• Periostium
• Membrane covering the bone
• Marrow cavity
• Space in the diaphysis
• Endosteum
• Lining of the medullary cavity

3. Principles of Fracture Healing

4. • Bone Consists
• Organic component (%40)
– Collagen
– Proteoglicans
– Matrix proteins
• İnorganic component (%60)
– Calsiyum hidroksiapatite [Ca10(PO4)6(OH)2]
– Osteocalsiyun Phosfate

5. Types of Fracture Healing
1. Primary Healing
2. Secondary Healing
3. Distraction Osteogenesis

6. • Primary fracture healing
– Involves direct attempt by the cortex to reestablish
itself
– Occurs only with anatomic reduction & rigid fixation
– Gaps in reduction heal by vessel ingrowth-
mesenchymal cells- osteoblasts-osteoclast cutting
cones
– Direct contact areas heal by cutting cones allowing
passage of vessels

7. • Secondary fracture healing
– Response of periosteum/ external soft tissues
– Recapitulation of embryonic intramembranous
ossification and endochondral bone formation
– Intramembraneous= peripheral to fracture
– Endochondral= adjacent to fracture
– Motion enhances periosteal response
– External soft tissue forms bridging calus (endochondral)

8. Stages of Healing
 Hematoma Formation 1-2 Days
 Inflammation 2-7 Days
 Soft Callus Formation 1-3 Weeks
 Hard Callus Formation 3-6 Weeks
 Remodelling Phase >8. Weeks

9. Hematoma Formation
• Hematoma forms in
medullary canal and
surrounding soft tissue
in first 24-48 hours

10. Inflammation
• Hematoma in fracture site brings hematopoietic cells secreting
growth factor
• Growth factors
– Insulin-like growth factor (IGF-1)
– Transforming growth factor (TGF)
– Vascular endothelial growth factor (VEGF)
– Fibroblast growth factor (FGF)
• Fibroblasts, osteoprogenitor cells produce granulation tissue
around fracture ends
• Osteoblasts proliferate
• By 1st-2nd week, abundant cartilage over fracture site ready for
calcification (occurs identical to growth plate)

11. Inflammation
Periost
Devitalized marrow
Endosteum
Hematoma
Dead osteocytes/empty lacunae
WBC
Angiogenesis
Granulation
tissue

12. Soft Callus ( Fibrous Callus) Formation
• Fibrous tissue forms at periphery where blood
supply is abundant
• Fibrocartilage forms at center where blood supply
is limited
• Increased instability results in increased callus size
• Tissues bridge fracture and decrease
interfragmentary strain

13. Soft Callus ( Fibrous Callus) Formation
Granulation tissue
Fibrous tissue
Fibrocartilage

14. Hard Callus Formation
• Intramembranous
ossification
• bone from fibrous tissue
• Endochondral ossification
• bone from cartilage

15. Hard Callus Formation
Fibrous tissue
Intramembranous
ossification
Fibrocartilage
Endochondral
ossification

16. Remodelling Phase
– Begins in middle of repair phase, continues until fx
clinically healed
– Osteoclastic tunneling (cutting cones) in concert
with osteoblast deposition
– Can continue up to 7 years
– Remodeling based on stresses (Wolff’s law)
• Bone formed in response to mechanical load

20. Distraction Osteogenesis
• Gradual traction applied to cortical osteotomy
• Bone forms under the law of tension stress
• Wolff’s Law occurs even with tension
• Typically intramembranous ossification
• Used in limb lengthening
• Treatment of limb deformities
• Transportation of cortical bone

21. Conditions that interfere with fracture healing
• High energy traumas brings soft tissue problems that lead non unioun
• Poor blood supply to the fractured area; could lead to avascular or aseptic
necrosis
• Poor immobilization of fracture site may cause misalignment, nonunion or
deformity
• Infection – more common with open fractures
• Cortisone= negative effect, decreased callus formation

22. THANK YOU