How are impingement and rotator cuff tears diagnosed?
With a careful history and physical examination, impingement and rotator
cuff tears can be easily diagnosed in the doctor's office. Further
testing may be necessary to determine the exact nature of a rotator
cuff tear.
After the evaluation of symptoms, the doctor
will perform certain muscle tests to determine whether
there are tears in the rotator cuff tendons and to rule out other
conditions. The doctor may place the arm in positions that reproduce
the described pain to confirm the diagnosis.
There are many tests that can isolate specific areas of pain and weakness
to help make the diagnosis. Further evaluation may include:
-
A diagnostic
injection can help the doctor distinguish between impingement
syndrome and a full thickness rotator cuff tear. A local anesthetic
is injected into the inflamed bursae to eliminate the pain.
If strength in the shoulder returns once the pain is blocked,
it is likely that the weakness was due to pain and the rotator
cuff tendons are not torn. A rotator cuff tear is suspected
if strength does not return while the pain is blocked.
-
X-rays
can reveal signs of arthritis, fractures, and bone spurs on
the acromion. They can also reveal changes in position of the
humerus and scapula that may suggest a rotator cuff tear. These
images are frequently negative in the early stages of injury
since X-rays show bone structure but not soft tissue.
-
An MRI (Magnetic
Resonance Image) allows the physician to see muscle
and other soft tissue not visible with X-ray.
-
An arthrogram
is another method used to help diagnose a rotator cuff tear.
A dye is injected into the shoulder and X-rays are made. If
a tear in the rotator cuff tendons exists, the dye will run
through the tear and make it visible on X-ray.
-
Ultrasound
may also be used to diagnose a tear; however, results
with this technology are difficult to evaluate and are very
dependent on the skills of the technician and radiologist.
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