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The
Injury
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The
supraspinatus, infraspinatus, teres minor and subscapularis
(s.i.t.s.) are
small muscles situated close to the glenohumeral joint
(ball-and-socket joint) of the shoulder. Collectively, they are known as the rotator cuff. Although they have individual
actions, their main role is to work together to stabilize the
humeral head (ball) in the glenoid (socket).
- People are often told that they have
injured one particular member of the rotator cuff, with the most
common diagnosis being supraspinatus tendonitis. However, it is
unlikely that the problem is with just one of the muscles in
isolation. Surgeons refer to such conditions as a 'rotator cuff
injury' and consider the picture as a whole.
- Although the rotator cuff can be
injured by a single traumatic incident, this is not common. Injury
to the rotator cuff will usually begin as inflammation (tendonitis)
caused by some form of microtrauma (a small but continuous source of
irritation). If the cause of the inflammation is not addressed, and
continues over a long period of time, partial tears may develop in
the cuff that could eventually become complete tears (a tear all the
way through one or more of the rotator cuff muscles).
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There are three main causes of
microtrauma to the rotator cuff:
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1. Primary
Impingement:
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- The coracoacromial arch forms a bridge over the
rotator cuff.
- It is made up of bones and ligaments and is lined by a sac
of fluid called the subacromial bursa.
- The space under the bridge that
is available for the rotator cuff is called the subacromial space.
- Many
people will have a naturally small subacromial space, which is just bad
luck, but the space can also be reduced by conditions such as
osteoarthritis.
- Whatever the cause of this small subacromial space,
repetitive overhead activities (such as throwing or dusting
high shelves) can cause the rotator cuff to become continuously squashed
against the coracoacromial arch, causing inflammation of the cuff.
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2. Secondary
Impingement:
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- Many people will have what is called shoulder
instability (a lax shoulder joint).
- This laxity may have been present
since birth or may be due to an injury.
- Often it will have occurred over
time due to repetitive overhead activity, poor posture or inactivity.
- Due to this instability, the rotator cuff has to overwork to stabilize
the shoulder, causing it to become inflamed. Eventually, the rotator
cuff will become weak and tired, and will not be able to prevent the
humeral head from squashing up against the coracoacromial arch. Because
this type of impingement is not due to a small subacromial space, it is
called secondary impingement.
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3. Overstraining:
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During forceful throwing actions the
rotator cuff has to work very hard.
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With repetitive throwing, the cuff
is prone to being overloaded, resulting in inflammation.
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Signs
and Symptoms
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- Weakness,
loss of full movement and shoulder pain.
- The amount of pain will depend on
the extent of the injury. Patients with early-stage inflammation may
only have pain with overhead activities, while those with a complete
cuff tear may not be able to sleep because of the pain.
- Physiotherapists have a number of
physical tests designed to diagnose the presence and severity of
rotator cuff injury. It is also important to look for signs of
shoulder instability. X-rays can give clues as to the presence of a
rotator cuff injury but an MRI scan is the investigation method of
choice to determine whether a tear is present. An ultrasound scan
may be just as effective if carried out by an experienced
sonographer.
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Treatment
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Tears of the rotator cuff are best treated
by surgical repair. Physiotherapy is often effective in treating acute
(short-term) and chronic (long-term) inflammation of the cuff where a tear
is not present.
- The first aim of treatment is to
reduce the amount of inflammation through electrotherapy, ice and anti-inflammatory medication prescribed by a doctor.
- A corticosteroid injection (an
injection of a naturally occurring substance that can slow down
inflammation) that bathes the rotator cuff, rather than being injected
directly into it, is advocated by some doctors. However, even this may
carry a risk of causing further damage and should be used with
caution.
- Once the inflammation and pain has
settled, exercises to regain full movement can begin, followed by a
carefully-graded strengthening and stabilizing programme.
- Faults in sporting technique that may
have caused the problem in the first place must also be rectified.
- Operative treatment of chronic
inflammation of the rotator cuff may be necessary if no progress is
made with physiotherapy. The use of surgery aims to enlarge the
subacromial space (subacromial decompression), thus reducing the risk
of impingement.
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Prevention
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- Attention
must be paid to flexibility, strength and endurance of the shoulder
muscles, ensuring that the muscles of the scapula are not neglected.
- Learning the correct technique and
choosing proper equipment is important.
- Any
increases in the amount of training or competition must be gradual.
- A
proper warm up and cool down may also help to prevent injury.
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