Fracture healing is a complex regenerative process involving several stages: inflammation and hematoma formation, callus formation through cartilage and bone tissue, consolidation into solid bone, and remodeling. There are two main types of healing - primary/direct healing where bone forms directly across the fracture without callus, and secondary/indirect healing which involves initial callus formation. Many factors can influence healing, including systemic factors like nutrition, age, and diseases, as well as local factors like blood supply, fracture stability, and treatment approach. Complications can arise if healing is delayed or impaired. Understanding fracture biology and influencing factors is important for orthopedic surgeons to ensure proper bone regeneration and recovery from injury.

1. Foundation Gracias Clinics
Topic:
FRACTURE HEALING
Presented by
DR ODOH ARINZE .J.

2. OUTLINE
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Learning Objectives
Introduction
Brief History
Structure of the Bone
Bone Healing
Types of Bone Healing
Sequences of Fracture Healing
Factors affecting Healing
Complications
Conclusion
Take Home message
References

3. Learning Objectives
By the end of this Discussion:
• Reinforce the knowledge of bone healing
• Understand the processes in indirect healing
• Understand the processes in direct healing
• Acknowledge the importance of the various
cellular signaling molecules involved in fracture
healing

4. Introduction
Fracture is defined as
Break in continuity of bone either partial
or whole resulting in loss of its
mechanical stability with partial/complete
destruction of blood supply
Healing is Defined as:
The process of returning to health ie the
restoration of structure and function of an
injured or diseased tissue

5. Introduction
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Fracture Healing is one of the most
important if not the primary concern of
every Orthopaedic Surgeon
The Study of repair of Musculoskeletal
system must begin with an
understanding of the nature of biologic
response to osseous injury and repair

6. Intro Contd
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Following fracture –there is a complex
and dynamic affair with succession of
changes commonly involved in
restoration of the part by mesenchymal
tissue i.e, bone.
So in fracture Healing, no scar is
formed instead a bone has formed a
new at the original fracture site. So in
otherwords the appropriate
nomenclature would be bone
regeneration.

7. Brief History
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Bones have fractured since the beginning of
humanity & treated as long as recorded in
history.
First described by Ham and Harris in 1956
using rabbit model
In 17th Century, Albrecht Haller, observed
invading capillary buds in fracture callus and
taught that blood vessels are responsible for
callus formation.
John Hunter, described the morphologic
sequence of fracture healing.

8. History Contd
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In 1873 , Kolliker observed the role of
multinucleated giant cells, osteoclast to be
responsible for bone resorption.
In 1917, Bier reported the stimulation factor
for new bone formation was present in
organized clot of the fracture hematoma.
In 1939, Gluksman suggested pressure and
shearing stresses are possible for
fracturehealing.
In 1961, Tonna and Cronkie demonstrated the
role of local mesenchymal cells in a fracture
repair.

9. Structure of Bones
 Bones are unique structure with several
specific functions
- Major Reservoir of calcium
- Support to the frame of the body
- Origin and insertions of muscles
- Protects vital soft tissues
- Locomotion
- Production of RBCs
- Storage & production of fats

10. Structure Contd
 Cells Found in Bones
Osteoprogenitor cells
• They arePluripotent mesenchymal stem
cells found in bone which differentiate into
osteoblasts
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Found throughout the bone and also known
as preosteoblasts or Osteogenic cells
• As they become trapped in the organic
matrix they become osteocytes

11. Structure Contd
Osteoclast
•derived from fusion of many monocytes
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They are large phagocytic multinucleated
cells
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They break down bone after senescence of
or trauma to osteocyte, normal bone
remodelling
•cytoplasm is eosinophilic and has a ruffled
border
•present on the surface of bone being
reabsorbed and occasionally free in bone

12. Structure contd
Osteoblast
•derived from osteoprogenitor cells
•create bone tissue de novo and entrap
themselves
in small spaces called lacunae.
•long processes from the cell lie in channels
called canaliculi through which these cells
communicate with other cells .
•osteoblast within a lacunae surrounded by
bone matrix and further differentiation is called
as an osteocyte and is responsible for strength
and integrity of the bone

13. Structure contd
BONE LINNING CELLS
• Are flattened epithelium in adult skeleton
found on resting surfaces.
• Plays active role in differentiation of
progenitor cells
• Controls osteoclasts, mineral hemostasis
and may secrete collagenase.
• Lines – endosteal surface of marrow cavity
- periosteal surface
- vascular channels within osteons.

14. Structure Contd
Types of Bones
• Woven (Immature bone): Characterized by
random arrangement of cells and collagen,
associated with periods of rapid bone
formation such as in initial stage of fracture
healing.
• Lamellar bone (Mature bone) : Characterized
by an orderly cellular distribution and
properly oriented
collagen fibers . This constitutes organized

15. Structure Contd
Harvesian
Canal
Volkman’s
Canal

16. Bone Healing
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Healing starts as soon as fracture occurs
Healing proceeds through several stages
until the bone is consolidated
The pattern of healing is different for
different bones in different circumstances
Complex process require recruitment of cells
Subsequent expression of genes at time and
location
A fracture initiates a sequence of
inflammation,
repair, remodelling that can restore the

17. Bone Healing Contd
• Among the few tissue that heals without
formation of scar tissue, Stages in bone
healing resembles embryonic development
• By its end would form tissue almost exactly
the
same as prior to injury
• Therefore is mainly a regenerative process
rather than reparative

18. Types of Fracture Healing
 In Man Fracture healing Occurs in 2
main ways
1. Primary healing/Direct healing
- Gap Healing
- Contact Healing
2. Secondary Healing/Indirect Healing

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Primary/ Direct Healing
This is also known as Intra membraneous
repair/Osteonal remodelling/ Haversian
remodeling.
Bone formation occurs directly without any
callus formation. This occurs in stable,
aligned, closely apposed fractures.
Also seen in cancellous/cortical bone.
Schenk and Willenegger described 2 types of
primary bone healing
– Gap healing
– Contact healing

20. Contact healing
• Lamellar bone forms directly across the
fracture, parallel to long axis of bone by
direct extension of osteons.
• A cluster of osteoclasts cuts across the
fracture ,
osteoblasts following the osteoclasts deposit
new bone and blood vessels follow the
osteoblasts.
• These“cutter heads” or “cutting cones” form
new haversian systems or primary osteons

21. Gap Healing
• Gaps between bone fragments are invaded
by blood vessels which appear within the
first 8days.
• Accompanied by osteoblasts which deposit
osteoid, giving rise to lamellae oriented 90°
to the long axis of the bone
• From 4th week onwards haversian
remodeling begins with cutting cones
traversing the new bone in the fracture gap
depositing lamellar bone and forming axially
oriented osteons

22. Secondary/Indirect Healing
• It is usual the type consisting of formation of
callus either of cartilagenous or fibrous.
• This callus is later converted into lamellar
bone.
• When fracture is not rigidly fixed and
movements occur, in such case callus is
replaced by secondary bone healing.
• Radiologically characterized by callus
formation, temporary widening of fracture and
slow disappearance of radiolucent fracture
line due to fibro cartilage mineralization.

24. Sequence of Events of
Fracture Healing
 Bone healing proceeds in successive stages.
• Each stage depends on different kinds of
differentiated cells to make new capillaries,
local connective tissue and bone and
cartilage matrices ( made by osteoblast
and chondroblast)

25. Primary/Direct Healing
The natural course of fracture healing includes:
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1. Stabilization of the fractured bone fragments
by periosteal and endosteal callus formation
and by fibrocartilage differentiation.
2. Restoration of continuity and bone union by
ossification.
3. Substitution of avascular and necrotic areas
by haversian remodelling.
4. Malalignment may be corrected , to a certain
extent, by remodelling at fracture site.

26. Primary bone Healing without
callus formation

27. 
Secondary/Indirect Healing
– Tissue destruction and stage of hematoma formation:
Hematoma forms from torn vessels.
– Inflammation & cellular proliferation/granulation tissue
Inflammatory cells absorb hematomangiogenesis.
– Callus formation/repair
Stem cells differentiate under influence of growth factors
and form cartilage, woven bone Callus.
– Consolidation
Woven bone converted to lamellar bone.
– Remodeling
Crude weld of solid bone is reshaped according to
physiological
forces over years.
NOTE: These stages overlap and are determined only

30. 
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These factors can be subdivided into
1. Systemic Factors
2. Local factors.
• Systemic factors present at the time of injury with
exception of trauma to the CNS.
• Local factors subdivided according to their
nature such as
- Mechanical , - Chemical
- Physical - Environmental.
Such classification has little clinical importance
Factors Affecting Healing

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Systemic Factors
1. Age
Children
Adults
2. Activity level including
General immobilization
Space flight
3. Nutritional status
VitD
Calcium
4. Hormonal factors
GH
Corticosteroids(microvascular AVN)
others- thyroid, estrogen , androgen, calcitonin,
PTH,PG

32.  System Factors Contd
5. Diseases:- anemia, neuropathies, tabes,
Diabetes
6. Vitamin deficiency: A,D,E,K
7. Drugs : NSAIDs, anticoagulants, sodium,
fluride, tetracycline.
8. Cigarette smoking and alcohol
9. Hyperoxia
10. Systemic growth factors
11. Environmental temperature
12. CNS trauma

33. Local Factors
A. Factors independent of injury, treatment, or
complications
1. Type of bone
2. Abnormal bone
radiation necrosis
infection
tumours and other pathologic conditions.
3. Denervation

34.  Local Factors Contd
B. Factors Dependent on Injury
1. Degree of local damage
i compound #
iii comminution of #
iii velocity of injury
iv low circulation levels of vit.K
2. Extent of disruption of vascular supply to bone, it’s fragments,
soft tissue or severity of injury.
3. Type and location of fracture ( ½ bones ie tibia and fibula or
tibia alone.
4. Loss of bone
5. soft tissue interposition
6. Local growth factors

35. Local Factors Contd
C Factors depending on treatment
1.Extent of surgical trauma( blood supply, heat)
2. Implant induced altered blood flow
3. Degree and kind of rigidity of external/internal
fixation and influence of timing
4. Degree, duration and direction of load induced
deformation of bone and soft tissue
5. Extent of contact b/w fragments
6. Factors stimulating post traumatic osteogenesis like
bone graft, BMPs, electrical stimulation ,surgical
technique, intermittent venous stasis

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Local Factors Contd
D. Factors associated with complications
1. infection
2. venous stasis
3. metal allergy

38. Complications
 Major complications of fracture repair
includes
1 Osteomyelitis
2. Delayed Union
3. Non-Union
4. Mal-union
5. Fracture associated Sarcoma

39. Conclusion
• Bone healing is an important aspect of trauma
management that need to be understood
• Surgeons must recognize the importance of
preserving the biology of a fracture to ensure
good bone healing
• Many areas of this process could be utilized in
managing complications of fracture (e.g.
nonunion)

40. Take Home Message
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Bone has the Regenerative capability just like
the Liver so instead of Reparative its called
Regenerative healing
Bone Healing can either be Primary/direct or
secondary/Indirect
The Healing can be affected by some factors
which can either be local or systematic
There are also complication which can arise
from the different levels of fracture healing
Fracture Healing is the primary concern of
every Orthopaedic surgeon

41. REFRENCES
Smith JJ. Common Surgical Emergencies. http://
www.jjs.me.uk/teaching/surgicalemergencies.html
Omoke NI, Ekumankama FO. Incidence and Pattern
of Extremity Fractures seen in Accident and
Emergency Department of a Nigerian Teaching
Hospital. Niger J Surg 2020; pg26:28-34
Bailey &Love’s short practice of surgery 25th
edition chapter 21, page 3-32
Principle and Practice of Surgery by E.A Badoe , E.
Q Archampong, J.T da Rocha-Afodu , 4th edition
chapter 54, page 1135-1145