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Shoulder Impingement

Shoulder Impingement - Why does this happen?
The shoulder is a ball and socket joint.  The round head of the humerus sits in a shallow socket on the shoulder blade.  Above the ball and socket is the acromio-clavicular ligament which is attached from the bony area on top of the shoulder blade, the acromion, to the end of the collarbone.  This forms an arch.
The area under this arch is known as the subacromial space.  The rotator cuff muscles are a group of 4 muscles that allow the shoulder joint to move in a controlled way.  The large arm muscles provide power for movement whilst the rotator cuff muscles act like guide ropes on a tent.   The tendons of these muscles pass through the subacromial space and are cushioned from the arch by a small fluid filled sack, the bursa.
When the arm is lifted the rotator cuff muscles keep the ball of the joint centred in the socket and stop it hitting against the arch above.  The bursa allows the rotator cuff to glide under the acromion, acting like a cushion.
Normal wear and tear of the muscle, overuse, repeated overhead movements and sudden lifting or poor posture can cause irritation of the rotator cuff.  The muscles do not keep the ball centred in its socket, and it pushes up into the arch causing inflammation and thickening of the bursa.  If this continues, bone spurs may develop under the end of the collarbone or the acromion, resulting in a reduced subacromial space with potentially more pressure placed on the muscles.  The rotator cuff starts to rub against the acromion when the arm is raised.  This 'pinching effect' is referred to as an impingement
Many people will experience some degree of impingement due to the day-to-day activities they perform with the arm held above shoulder level.  Impingement may become a problem for some people when pain disturbs their normal daily activities.  This is when treatment is required. 
What are the symptoms?
  • Subacromial Impingement is a common condition affecting people between the ages of 40 and 60.
  • Pain is located on the top of the shoulder and can spread into the upper arm.  The pain is made worse by movements such as lifting the arm above shoulder level or rotation activities like putting on a coat.
  • Some people will complain of pain at night, particularly when lying on the affected side.
  • The pain ususally develops spontaneously without a specific history of injury.
  • Initially the pain is intermittent and mild.   
Diagnosing a Shoulder Impingement 
Your GP or Physiotherapist can usually diagnose Subacromial Impingement simply by examining your arm, knowing where your pain is and how it started.  X-rays and other investigations are not usually necessary during the first episodes of pain.
What is the treatment?
Modifying activities  -  The first thing to do is break the pain cycle.  While it is important to stop activities that make the pain worse, to let the tendon recover, you must not stop using your arm.  Muscles need some activity to keep them healthy.
Painkillers and anti-inflammatory medications  -  These may be prescribed by your GP if the pain is constant and you are struggling to sleep.  This is a temporary measure to break the pain cycle, but can continue as required.
Exercise  -  Exercise is the most effective way of helping the tendons recover and re-learn how to do their job properly.  This can help prevent further episodes of pain.  Most people following an exercise schedule can recover over a period of 6 - 12 months with an improvement in the symptoms seen within 6 -12 weeks of starting the exercises. Click here for a list of exercises suitable for a Shoulder Impingement.   
Steroid Injection  -  These can be used to reduce inflammation in the bursa when pain is severe and constant, or if sleep is affected.  This is not a 'cure' and it is important to follow the exercises and modify activities.  
Physiotherapy  -  If exercise alone does not improve symptoms or if there is joint stiffness, neck pain or other factors that make doing exercise difficult then physiotherapy treatment may be required.  Click here for more information about Physiotherapy.
Surgery  -   In some cases if pain does not improve with the above intervention, you may need to see an Orthopaedic Surgeon.  Further assessment and tests by an Orthopaedic Surgeon will give more information.  In some cases surgery may be required to create more space for the rotator cuff tendons
Remember an important part of treatment for a Shoulder Impingement is your home exercises and modifying activities.