Bone Fracture Healing

8/2/2019 Bone Fracture Healing

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BonesFracture Healing

GMU / Department of Pathology

3rd MBBS

Integrated Curriculum

Dr. Ghaith J. Al Eyd

M.B.Ch.B., M.Sc., Ph.D., M.I.A.C.


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Learning Objectives:

Review the anatomical regions and the histology of bone. Review the physiology of bone resorption & formation.

describe the types of fractures.

Describe the process of fracture healing.

Describe the complications of fracture healing.


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Anatomic Regions of Long Bone:
http://www.kumc.edu/instruction/medicine/pathology/ed/ch_26/c26_s1.jpg


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Bone resorption and formation are coupled processes

that are controlled by systemic factors and local cytokines, some of

which are deposited in the matrix.

Cytokines (e.g. BMPs, FGF, PDGF, insulin like growth factor, and

TGF-) are key in the communication between osteoblasts andosteoclasts.

Bone Resorption and Formation:


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Fractures:

Traumatic and nontraumatic fractures are some of the most common pathologic

conditions affecting bone.

Fractures are classified as:

Complete fracture.

Incomplete fracture(green stick fracture): The bone is cracked, but not

broken into two pieces.

Closed (simple) fracture: The overlying tissue is intact.

Compound fracture: The fracture site communicates with the skin surface.

Comminuted fracture: The bone is splintered.

Displaced fracture: The ends of the bone at the fracture site are not aligned.

Pathological fracture: The break occurs in bone already altered by a disease

process.

Stress fracture: Slowly developing fracture that follows a period of increased

physical activity in which the bone is subjected to new repetitive loads as in

sports or marching in military boot camp.


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Complete

fracture

Incomplete

fracture Greenstick

fracture

Closed

fracture

Compound

fracture Compoundfracture

Displaced

fracture

Comminuted

fracture


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Fracture Healing:

Bone is unique in its ability to repair itself; it can completely

reconstitute itself by reactivating processes that normallyoccur during embryogenesis.

Fracture healing is similar to wound healing except that the

granulation tissue that has formed is to be converted to bonetissue.

This is achieved by activation of osteoprogenitor cells and

osteoclasts through mediators (Interleukins & growthfactors) released from inflammatory cells and platelets.


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Fracture Healing:

Immediately after fracture, rupture of blood vessels results in a hematoma,

which fills the fracture gap and surrounds the area of bon injury. This is

followed, in the first few days, by influx of inflammatory cells and,

removal of necrotic debris.

The hematoma undergoes organization by ingrowth of granulation tissue at

the end of first week. This fusiform granulation tissue bump at the

fracture site is calledprocallus or soft tissue callus.

Callus: Granulation tissue (containing osteoprogenic cells, osteoblasts and

osteoclasts) at the fracture turns into a mass of fibrous tissue, bone

and cartilage, from which healed bone will arise. Maximal girth of

callus is reached at the end of second or third week.

Eventually it becomes bony callus and then remodels to look more or less

like the original bone.


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Fracture Healing:


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Fracture Healing:


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Fracture Healing:


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Fracture Healing - Complications:

Inadequate immobilization may lead to delayed union or non

union.

Pseudarthrosis: The ends of the bone did not heal back

together with bone. At best, there is fibrous scar connecting

the ends, and a "false joint" is created.

Infection of fracture site in open fractures.

If the fracture iscomminuted, ifthe ends of the bones are

much displaced, or ifinfection happens, don't expect

good healing. Likewise,poorly-nourished people or

osteoporotic people are likely to get bad results.


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Bone Fracture Healing

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