Much of an orthopedic practice involves various types of
injections, and the right shot in the right place at the right time
can be very effective. However, there are a number of myths and
misconceptions about injections. This article will provide you a
The types of injections that we do in our practice can be
categorized as "Intramuscular", "intraarticular", "trigger point"
and "epidural". These categories are based on where the shot is
placed. Intramuscular injections are more commonly
done by internists. The material is injected into a muscle
and allowed to be gradually absorbed by the body. Intraarticular
injections are "into a joint" (that is what the word means). These
may be large joints, such as the knee or shoulder, small joints,
such as the hand and fingers, or in between. Knee and
shoulder joint injections are common. Hip joint injections are
rather rare and are often done with an x-ray machine, As this is a
very deep joint. Trigger point injections are done into a muscle,
or tendon area that has been identified as causing pain.
The pain is triggered when the area is pressed. Epidural injections
are inside the spine next to the membrane (the "Dura") that encloses
the spinal fluid and spinal cord or spinal nerves. These may be
in the neck (cervical) or low back (lumbar). In our
practice, when we say "epidural" injection, we mean an "epidural
steroid" injection, that is, a cortisone derivative. In the lower
back, an "epidural" injection using an anesthetic agent is used for
or childbirth and involves similar techniques, but a
different medication. Facet blocks in the neck or lower back are
injections of the small joints that are part of the spine and are
really types of "intraarticular" injection.
The term "steroids" is a general term. Cortisone is an
"adrenal" steroid that is produced in the adrenal gland. It is
different from male and female hormones, which are also steroids and
very different from anabolic steroids, which get much attention
in the media for their illegal use in sports. "Cortisone"
itself is produced in the body. When we use the term, we really mean
semi synthetic cortisone, of which there are several types, all
having a very similar action. These medications, such as
Methylprednisolone, triamcinolone and betamethasone, have
longer durations of action than cortisone itself and give more of
the desired effects with less of the side effects.
Reactions, or side effects, to cortisone shots are
relatively rare and relatively mild. Diabetics will notice an
increase in blood sugar, although rarely a cause for concern.
Tenderness at the injection site occurs more in small joints or with
Injections, usually lasts no more than 48 hours, and is
improved with ice, but made worse with heat. For some time,
injections of cortisone derivatives into joints were Felt to be
related to producing arthritis, which has not been shown to be the
Recent studies using the local anesthetic Marcaine in a
more concentrated form may not be good for cartilage and our
practice does not use this medication for those injections. Steroid
(cortisone) injections into tendons may lead to tendon weakening,
And these injections are rarely done. Injections near, but
outside the tendon, are much more common.
In addition to the steroid injections, "cartilage gel"
injections (technically called visco supplementation) are available.
There are five brands of this. The first four are derived from
chickens (rooster combs) and the fifth from bacteria. Both of these
hyaluronic acid derivatives, which is the building block of
cartilage. Most of these will provide eight out of ten people relief
for six months or more. Medicare does have specific rules regarding
its use (and most other insurance companies follow Medicare).
These are that the ideal patient is not markedly
overweight, that their x-rays show some degenerative change, but not
severe, pills for pain or arthritis should have been Tried (or there
is a reason why they cannot be used), and possibly a trial of
cortisone shots first. Medicare rules allow for a subsequent series
of injections (usually three, but with one brand five). This can be
repeated after six months. The rules also provide that if one series
of any of them is done and does not work, then another series, even
of a different one, will not be approved. (That is why we have to
provide An "Advancement Beneficiary Notice" to each patient who is a
candidate for these injections.) The cartilage gel injections also
are only approved for use in the knee. There are indications that
they may be useful in the ankle and the shoulder, and perhaps other
joints, but since that is an "off label" use, it is legal to do
insurance will not cover it. The final question is how many
shots a patient can have? The answer to this is "as
many as continue to work". I have already discussed the
cartilage gel limitations. As far as "cortisone" shots are
concerned, the rumors of "three in a lifetime", "three in a year” or
"three in the same joint" have no basis. Usually, we would like to
see three or four months of relief after a "cortisone" shot before
considering another although there are exceptions to this rule. The
same rule applies to "epidural" Injections. The common practice of
scheduling three injections in a row is not encouraged by the
Academy of Orthopaedic Surgeons, who recommend that a single
injection be done and the results observed to see whether further
injections are necessary. (If they are, then they would be done.
After an initial series of "epidural" Injections, it is a good to
wait three to four months for further injections.)
I hope this gives you more information on what shots are
for and how they work. For specific questions, when you come to the
office, please discuss it with us and we will answer any further
questions you may have.
John Van Houten, M.D.