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U N I T 1 2
Musculoskeletal Function
within the capsule of the hip joint. Intertrochanteric
fractures occur in the metaphyseal region between the
greater and lesser trochanter. Subtrochanteric fractures
are those that occur just below the greater trochanter.
The location of a hip fracture is important in terms of
blood flow to the femoral head, which receives its blood
supply from vessels that course proximally up the fem-
oral neck
10
(see Fig. 43-4). Subtrochanteric and inter-
trochanteric fractures that occur distal to these vessels
do not usually disturb the blood supply to the femoral
head, whereas femoral neck fractures, particularly those
involving marked displacement, often disrupt the blood
supply to the femoral head and are therefore associated
with an increased incidence of complications (nonunion
and avascular necrosis).
Most hip fractures are diagnosed based on clinical
findings and standard radiographs. A bone scan or MRI
may be done when the radiograph is negative, but the
clinical findings support the diagnosis of hip fracture.
The primary goal of treatment for a hip fracture is a
return to the preinjury level of function as soon as pos-
sible.
8
Undisplaced or impacted fractures have a bet-
ter prognosis in terms of healing and are often treated
nonoperatively or by simple internal fixation to provide
stability. Displaced intracapsular fractures in the elderly
are usually best treated by surgical hip replacement and
early mobilization.
5
Young, healthy people are treated
by reduction of the fracture (if needed) and internal fixa-
tion. This method allows for preservation of the femoral
head, which in this age group is desirable because the
long-term results are better than with prosthetic replace-
ment. Intertrochanteric fractures are usually treated with
open reduction and internal fixation. This allows for
early ambulation by eliminating pain at the fracture site.
Fractures
A fracture represents a disruption in the continuity of
a bone.
8,18,19
Normal bone can withstand considerable
compression and shearing forces and, to a lesser extent,
tension forces. A fracture occurs when more stress is
placed on the bone than it is able to absorb. Grouped
according to cause, fractures can be divided into three
major categories: (1) fractures caused by sudden injury,
(2) fatigue stress fractures, and (3) pathologic stress
fractures. The most common fractures are those result-
ing from sudden injury. The force causing the fracture
may be direct, such as a fall or blow, or indirect, such
as a massive muscle contraction or trauma transmitted
along the bone. For example, the head of the radius or
clavicle can be fractured by the indirect forces that result
from falling on an outstretched hand.
Stress fractures are incomplete fractures.
8,20
They
may be described as either fatigue or pathologic frac-
tures.
Fatigue stress fractures
occur when excess stress is
applied to normal bone. They may occur in any weight-
bearing bone, but they are most common in the metatar-
sal, neck of the femur, calcaneus, tibia, fibula, and pelvis.
Fatigue stress fractures typically occur in unconditioned
athletes. Clinically, a history of unusual stress with
subsequent pain over a bone is common in fatigue frac-
tures. Stress fractures in the tibia may be confused with
“shin splints,” a nonspecific term for pain in the lower
leg from overuse in walking and running, because they
frequently are not apparent on x-ray films until 2 weeks
after the onset of symptoms.
4,5
Pathologic stress fractures
occur when normal stress
is applied to bones that have been weakened by disease
or tumors.
8
Fractures of this type may occur spontane-
ously with little or no stress. The underlying disease
state can be local, as with infections, cysts, or tumors, or
it can be generalized, as in osteoporosis, Paget disease,
or disseminated tumors.
Classification
Fractures usually are classified according to location,
type, and direction or pattern of the fracture line
5,8
(Fig. 43-5). A fracture of the long bone is described in
relation to its position in the bone—proximal, midshaft,
and distal. Other descriptions are used when the frac-
ture affects the head or neck of a bone, involves a joint,
or is near a prominence such as a condyle or malleolus.
The type of fracture is determined by its commu-
nication with the external environment, the degree of
break in continuity of the bone, and the character of the
fracture pieces. A fracture can be classified as open or
closed. When the bone fragments have broken through
the skin, the fracture is called an
open
or
compound
fracture.
In a closed fracture, there is no communication
with the outside environment.
Proximal
Midshaft
Distal
Comminuted
Transverse
Segmental
Oblique
Butterfly
Spiral
Impacted
FIGURE 43-5.
Classification of fractures. Fractures are
classified according to location (proximal, midshaft, or distal),
the direction of fracture line (transverse, oblique, spiral), and
type (comminuted, segmental, butterfly, or impacted).
