Many of us take our shoulder function for granted until simple tasks such as lifting overhead, scratching your back or wearing your favorite tight T shirt becomes a painful chore. There are many causes of shoulder pain such as the common frozen shoulder, tendonitis or even arthritis of the shoulder joint. In this article, I would like to share with you the most common cause of shoulder pain I see in my sports practice.
Shoulder impingement is one of the most common causes of pain in the adult shoulder. It results from pressure on the rotator cuff on the acromion as the arm is lifted. The acromion is the front edge of the shoulder blade. It sits over and in front of the humeral head. As the arm is lifted, the acromion rubs or "impinges" on the surface of the rotator cuff. This causes pain and limits movement.
The pain may be due to
a. “bursitis" or inflammation of the bursa overlying the rotator cuff tendon
b. “tendonitis" or inflammation of the cuff tendon
c. a tear of the rotator cuff tendon
Impingement is more common in people aged 30 and above. Those who do repetitive lifting or overhead activities using the arm such as lifting or racquet games are especially at risk.
Pain may also develop as the result of minor trauma or spontaneously with no apparent cause. The pain is usually in the front of the shoulder but many patients feel that the pain also “travels” down the side of the affected shoulder. It is worse when lifting the affected arm. There may be a clicking sensation when moving the shoulder. Ladies would complain of difficulty buckling their undergarments and gentlemen find putting on and taking off their T shirts painful. There may be pain and night and patients will not be able to sleep on their affected shoulder. Occasionally, they are woken up by the sharp pain when they turn in bed at night.
X-ray may show a bone spur/ hook on the front edge of the acromion. Further imaging studies, such as an ultrasound or MRI (magnetic resonance imaging) may be required to confirm a tear in the cuff tendon.
Arrow indicates the acromial bone spur/hook.
An impingement test, injection of local anesthetic into the bursa, can help to confirm the diagnosis.
Initial treatment is conservative and includes rest, avoidance of overhead activities and stretching exercises. A short course of oral non-steroidal anti-inflammatory medication may be necessary. Some patients may benefit from injection of local anesthetic and steroid into the affected area.
If conservative treatment does not relieve the pain, surgery may be required. The goal of surgery is to remove the part of the acromion (subacromial decompression) and create more space for the rotator cuff. This allows the humeral head to move freely without impingement against the acromion. This may be performed by either arthroscopic or open techniques:
In an arthroscopic procedure, two or three small puncture wounds are made. The joint is examined through a fiberoptic scope connected to a television camera. Small instruments are used to remove bone and soft tissue. This method is more commonly used as the incisions are small and the post-operative pain is minimal. A short video of this procedure can be seen at our website at www.iog.com.sg
Using a bone burr to remove the acromial hook
The other advantage is that the surgeon can confirm and treat other conditions present in the shoulder at the time of impingement surgery e.g. rotator cuff tear.
After surgery, the arm may be placed in a sling for a short period of time. As soon as the patient is comfortable, he/she may remove the sling and begin exercise and use of the arm. A rehabilitation program based on your needs and the findings at surgery will begin and it will include exercises to regain range of motion of the shoulder and strength of the arm. It may take two to four months to achieve complete relief of pain.