Subacromial Impingement

Causes of Subacromial Impingement

There are two primary reasons why you might develop subacromial impingement. If the muscles in your shoulder become weakened the arm bone may move closer towards the acromion causing the muscles to get pinched more frequently. Overusing your shoulder muscles by making repeated overhead movements can create small tears in the soft tissue, resulting in inflammation of the tendons and bursa. Once inflamed there is a greater chance of friction between the tendons and the acromion. You may also develop subacromial impingement following an injury which causes the muscles to catch under the acromion.

Symptoms of Subacromial Impingement

If subacromial impingement is due to overusing the shoulder muscles, the symptoms develop gradually whereas they may be sudden and severe following an accident. Symptoms include pain which is exacerbated by lifting your arm above your head or putting your hand behind your back. It may be painful to lie on the affected shoulder and this may affect your sleep. Your arm may feel weak and you might have problems lifting or reaching. If you are unable to move your shoulder for an extended period of time, you are at risk of developing a frozen shoulder so talk to your doctor about exercises to keep your shoulder as mobile as possible.

Diagnosis of Subacromial Impingement

Your doctor will carry out a physical examination and will ask you to move your arm to ascertain the range of motion you have. You may be referred for an X-ray or MRI scan to rule out other causes of shoulder pain, such as arthritis or a torn rotator cuff.

Treatment of Subacromial Impingement

Initially you may need to make some lifestyle changes to prevent the symptoms from getting worse. Painkillers and anti-inflammatories can help to relieve the pain and you may also be able to use an ice pack to reduce inflammation. A physiotherapist can recommend exercises to improve the range of movement in your arm and to relieve pain. Steroid injections into the affected area may be offered if the symptoms persist or get worse. These help to reduce inflammation and should be used alongside exercise. If non-surgical approaches fail to resolve the problem, you may be offered a surgical procedure called subacromial decompression. This is carried out arthroscopically (using keyhole surgery). It involves inserting a small camera into the subacromial space and using tiny surgical instruments to cut an additional space to relieve pressure on the tendons. In some cases surgical repairs to the tendons may be carried out at the same time.