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As medicine evolves
throughout the 21st century it is very likely that there will be
more and more inter-specialty dependence. That is to say that
unlike physicians who practiced medicine in the 1800s today's
doctors must increasingly rely on other physicians and
technologies from other specialties to treat their patients.
This should be evident as we continue looking at the different
imaging modalities used in a modern sports medicine practice.
For some people with
joint pain and for whom there is some question regarding joint
or muscle integrity a special variety of X ray may be used. This
is called an arthrogram. Although available for several joints
it is most commonly used to evaluate the shoulder joint.
The arthrogram works by
taking a plain film of the joint to begin with. Then a special
dye is injected into the joint. The dye is visible on subsequent
X rays. If the rotator cuff muscle does not have a full
thickness tear in it, the dye will remain confined to the joint.
If however the joint is
compromised by a tear in the rotator cuff muscle, the dye leaks
out of the joint. This has diagnostic significance since the
treatment for a full thickness tear versus other rotator cuff
pathology can be markedly different.
There are other forms
of specialized X rays that are used routinely in sports medicine
offices. These are called stress views. These show a
"snapshot" like view of joint function.
One situation where
stress views can be helpful is in evaluating ligament laxity
after a significant ankle sprain.
Though most ankle
sprains involving the lateral or outside of the ankle heel with
time and rehabilitation, a small percentage of them will be
chronically lax and may require a surgical procedure.
The lateral ankle can
be evaluated by first taking an X ray of both ankles in the
standard position. Then, an inversion stress (turning the foot
inwards) is placed on the ankle and another X ray is taken. In a
healthy person, the uninjured ankle will move approximately the
same degree as the injured ankle.
If the injured ankle
"opens up" more than the healthy one, the surgeon
knows that there is some laxity of the ankle and may consider
further rehabilitation or surgery, depending on the situation.
Ultrasound is another
modality that has both treatment and diagnostic applications in
the field of sports medicine. As reported in previous Sports
Medicine Today columns ultrasound can be used by physical
therapists and athletic trainers to treat a variety of
musculoskeletal conditions.
Ultrasound is also used
to diagnose certain conditions in medicine. In orthopaedics, it
is primarily used to evaluate patients for blood clots in the
veins of their legs.
Though anyone can
develop a clot at any time, certain things make the development
of these clots (called deep vein thromoses or DVT) more likely.
Specifically, being immobile for some time after a surgical
procedure is a common cause of DVT.
The consequences of DVT
can be quite serious. If one of these clots goes unrecognized
and untreated it can break loose and travel to the lung
circulation and occlude the blood supply to a portion of the
lung.
If a doctor clinically
suspects a DVT he or she typically orders a lower extremity
ultrasound to assess for clot. The ultrasound machine passes
sound waves into the leg. The radiologist can review the images
that are created and can often make the diagnosis of DVT. The
clot can then be treated and hopefully avert a dangerous lung
problem.
NASA is also
investigating ultrasound to allow minimally trained laypersons
to diagnose fractures and other conditions. One of the ongoing
problems with having people in space for prolonged periods of
time is that they must be able to care for themselves in a zero
gravity situation with only the equipment available on the
spacecraft. NASA asked the question "what if an astronaut
breaks his leg or arm and needs to diagnose and treat his
condition in space".
One of the proposed
ways of addressing this problem is with ultrasound. A small
ultrasound machine could be sent into space and, with a little
training, astronauts could use the ultrasound to diagnose a
variety of conditions from gallstones to fracture and view the
images themselves and also send them to earth for
interpretation.
In the next column we
will look at different varieties of imaging including the now
ubiquitous MRI.
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