BONE FRACTURE
MED121/LECTURE44
DR ZEENAT N.P.
PATHOLOGIST
COLLEGE OF MEDICINE
MAJMAAH
OBJECTIVES
• a.Define fracture & healing.
• b.Enlist common fractures.
• c.Describe traumatic & pathological fractures.
• d.Explain process of healing.
Define fractureDisconitnuity in the bone alignment
• Traumatic
• Nontraumatic fractures
• Most common pathologic conditions affecting bone. Fractures are classified as
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Complete or incomplete
• Closed (simple) when the overlying tissue is intact
• &.Open
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Compound when the fracture site communicates with the skin surface
Comminuted when the bone is splintered
Displaced when the ends of the bone at the fracture site are not aligned.
If the break occurs in bone already altered by a disease process, it is described as a
pathologic fracture.
• A stress fracture is a slowly developing fracture that follows a period of increased
physical activity in which the bone is subjected to new repetitive loads—as in sports
training or marching in military boot camp.
ENLIST COMMON FRACTURES
• Transverse fracture. In this type of fracture, the break is a
straight horizontal line going across the femoral shaft.
• Oblique fracture. This type of fracture has an angled line
across the shaft.
• Spiral fracture. The fracture line encircles the shaft like the
stripes on a candy cane. A twisting force to the thigh
causes this type of fracture.
• Comminuted fracture. In this type of fracture, the bone
has broken into three or more pieces. In most cases, the
number of bone fragments corresponds with the amount
of force required to break the bone.
Greenstick
• Occurs in children: bones soft and bend without fracturing
completely
• Open fracture. If a bone breaks in such a way that bone
fragments stick out through the skin or a wound
penetrates down to the broken bone, the fracture is called
an open or compound fracture.
• Open fractures often involve much more damage to the
surrounding muscles, tendons, and ligaments.
• They have a higher risk for complications — especially
infections— and take a longer time to heal.
Statistics
• Fractures of extremities most common
• More common in men up to 45 years of age
• More common in women over 45 years of
age
Before 75 years wrist fractures (Colle’s) most common
• After 75 years hip fractures most common
C/F of fractures:
• Impaired function.
• Deformity (unnatural alignment).
• Swelling.
• Muscle spasm.
• Tenderness.
• Pain.
• Impaired sensation.
Functions of the X-ray
• Localises fracture and number of fragments
• Indicates degree of displacement
• Evidence of pre-existing disease in bone
• Foreign bodies or air in tissues
• May show other fractures
• MRI, CT or ultrasound to reveal soft tissue
damage
FRACTURE HEALING
• The process involves regulated expression of a
multitude of genes
• can be separated into overlapping stages with
particular molecular, biochemical, histologic, and
biomechanical features.
Bone Healing
1. Fracture hematoma
– blood from broken vessels
forms a clot.
– 6-8 hours after injury
– swelling and inflammation to
dead bone cells at fracture
site
• Immediately after fracture, rupture of blood vessels
results in a hematoma, which fills the fracture gap
and surrounds the area of bone injury.
• The clotted blood provides a fibrin mesh, which
helps seal off the fracture site and at the same time
creates a framework for the influx of inflammatory
cells and ingrowth of fibroblasts and new capillary
vessels. Simultaneously, degranulated platelets and
migrating inflammatory cells release PDGF, TGF-β,
FGF, and interleukins, which activate the
osteoprogenitor cells in the periosteum, medullary
cavity, and surrounding soft tissues and stimulate
osteoclastic and osteoblastic activity
2. Fibrocartilaginous callus
• (lasts about 3 weeks (up
to 1 Month)
– new capillaries organize
fracture hematoma into
granulation tissue ‘procallus’
– Fibroblasts and
osteogenic cells invade
procallus.
– Make collagen fibers
which connect ends
together
– Chondroblasts begin to
produce fibrocartilage,
3. Bony callus
• (after 3 weeks and lasts
about 3-4 months)
– osteoblasts make woven
bone.
• by end of the first week
Hematoma is organizing, the adjacent tissue is being
modulated for future matrix production, and the
fractured ends of the bones are being remodeled.
This fusiform and predominantly uncalcified tissue—
called soft-tissue callus or procallus—provides some
anchorage between the ends of the fractured bones but
offers no structural rigidity for weight bearing.
• Subsequently, the activated osteoprogenitor cells
deposit subperiosteal trabeculae of woven bone that
are oriented perpendicular to the cortical axis and
within the medullary cavity.
• In some cases the activated mesenchymal cells in the
soft tissues and bone surrounding the fracture line
also differentiate into chondroblasts that make
fibrocartilage and hyaline cartilage.
• In an uncomplicated fracture, the repair tissue
reaches its maximal girth at the end of the
second or third week, which
helps stabilize the fracture site
• The newly formed cartilage along the fracture line
undergoes enchondral ossification, such as normally
occurs at the growth plate, forming a network of bone
that connects to the reactive trabeculae deposited
elsewhere in the medullary cavity and beneath the
periosteum.
• In this fashion the fractured ends are bridged by a
bony callus, and as it mineralizes the stiffness and
strength of the callus increases to the point that
controlled weight bearing can be tolerated
• In the early stages of callus formation an excess of
fibrous tissue, cartilage, and bone is produced.
• If the bones are not perfectly aligned, the volume of
callus is greatest in the concave portion of the
fracture site.
• As the callus matures and is subjected to weightbearing forces, the portions that are not physically
stressed are resorbed, and in this manner the callus
is reduced in size until the shape and outline of the
fractured bone have been re-established.
• The medullary cavity is also restored, and after this
has been completed it may be impossible to
demonstrate the site of previous injury
COMPLICATIONS OF FRACTURE
HEALING
• The sequence of events in the healing of a fracture can be easily
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impeded or even blocked.
For example, displaced and comminuted fractures frequently
result in some deformity,
Inadequate immobilization permits constant movement at the
fracture site, so that the normal constituents of callus do not
form, resulting in delayed union and nonunion.
If a nonunion allows too much motion along the fracture gap,
the central portion of the callus undergoes cystic degeneration,
And the luminal surface can actually become lined by synoviallike cells, creating a false joint or pseudoarthrosis.
A serious obstacle to healing is infection of the fracture site,
which is a risk in comminuted and open fractures. The infection
must be eradicated before bony union can be achieved.
• In children and young adults, in whom most
uncomplicated fractures are found, near perfect
reconstitution is the norm.
• In older age groups in whom fractures tend to occur
on a background of some other disease (e.g.,
osteoporosis and osteomalacia) repair is more often
imperfect and may require mechanical immobilization
(e.g., placement of stabilizing pins).
• MEDICAL MANAGEMENT
SURGICAL TREATMENT
External fixation
Intramedullary nailing provides strong,
stable, full-length fixation.
COMPLICATIONS FROM SURGERY
• Infection
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Injury to nerves and blood vessels
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Blood clots
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Fat embolism (bone marrow enters the blood
stream and can travel to the lungs; this can also happen
from the fracture itself without surgery)
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Malalignment or the inability to correctly
position the broken bone fragments
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Delayed union or nonunion (when the fracture
heals slower than usual or not at all)
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Hardware irritation (sometimes the end of the
nail or the screw can irritate the overlying muscles and
tendons)
•THANK YOU