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Orthopaedic surgeons
make use of dozens of diagnostic tools everyday in the
management and treatment of sports injuries. These range from
the relatively simple to the unbelievably complex and from free
to very expensive. From X rays to MRIs orthopaedists use over a
century of technology to help visualize the musculoskeletal
system to diagnose and treat injuries.
First of all its
important to point out that nothing can take the place of a good
history and physical examination. It is the sine qua non of
medicine and can never be replaced.
However, sometimes the
examination alone isn't enough to provide the diagnosis. In
these cases further diagnostic study is needed.
Which study is
appropriate is dependent on the nature of the problem, the
availability of diagnostic tools, the personal preference of the
doctor, and the economic feasibility of the test among other
things.
One of the oldest and
simplest diagnostic tools is the X ray. It has been used for
over a hundred years and has become a staple of orthopaedic
practice. Few if any orthopaedists can function without one in
or near their office.
X ray works by placing
the patient in between an X ray tube specialized film. The X
rays are emitted and travel towards the film. Things that block
the radiation from making it to the film cause images to be
produced on the film that are of diagnostic significance.
X rays allow doctors to
distinguish four shades of gray. For example, air is black and
metal (or other high density material) is white. This is because
air allows all of the X rays to make it onto the film whereas
metal blocks them all.
Other things visualized
on X ray are soft tissue and fluid. Things like muscle appear
one shade of gray and water and other fluids appear another.
X rays are fairly
cheap, allow good visualization of bony structures, and are
pretty good at allowing for the visualization of fractures and
the evaluation of the bony portion of joints.
Though some soft tissue
determinations can be made with X ray, it certainly doesn't to
the best job of defining soft tissue anatomy. However, X rays
are a good place to start with many problems and may indeed
provide the needed answers in many cases.
Sometimes the
diagnostic puzzle can't be solved with X ray alone. In these
cases, other modalities must be used.
In the same physics
ballpark as X ray is CT scan (cat scan is an older term for the
same thing). CT scanners also use X rays but display the
information in a different way.
Unlike conventional X
rays which allows doctors to see just four shades of gray, CT
allows the differentiation of 16 shades. And although there are
more shades, the same principles of density apply (metal and
high density subtances block the beam and air allows all of it
to pass through).
One easy way to think
of CT scanning is to think of the body as a loaf of bread. The
CT scanner makes slices through the body that allow the
visualization of different planes of tissue much like taking
away successive slices of bread from the feet to the head (or
whatever area is being scanned).
Though other areas of
medicine make more use of CT scans that orthopaedists, they do
have a significant role in the treatment of sports conditions.
For example, CT scans do an excellent job of defining joint
surfaces like the socket of the shoulder and the hip. If there
is a question of whether or not the articular surface has been
involved in a fracture and plain X ray films don't furnish the
answer, CT is an excellent choice to provide the solution.
Along with other
imaging modalities, CT is also used to evaluate the spine. X
rays don't always provide enough information about the spine to
make clinical determinations. CT can be extremely useful in
these situations.
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