Shoulder impingement syndrome (SIS) results from pressure on the rotator cuff from part of the shoulder blade (scapula) as the arm is lifted. This pressure is a common cause of pain in the adult shoulder.
The major joint in the shoulder, called the gleno-humeral joint, is between the cup of the scapula (glenoid) and the ball of the arm (humeral head). This cup and ball are surrounded by the rotator cuff. The rotator cuff is made up of four muscles (the supraspinatus, infraspinatus, teres minor, and subscapularis) which work together to lift and rotate the arm at the gleno-humeral joint.
Above the rotator cuff is a projection of bone from the scapula called the acromion. Between these two structures lies a collection of cushioning fluid called a bursa. As the arm is lifted the space between the acromion and the humeral head gets smaller and the two structures in-between, the rotator cuff and bursa, get compressed or “impinged”. This causes pain and limits movement.
The pain may be due to a “bursitis,” or “tendonitis”. Bursitis is inflammation of the bursa, while tendonitis is inflammation of the tendons of the rotator cuff. This inflammation is painful. In some circumstances, repetitive impingement of the rotator cuff can cause a partial tear in the cuff. This can also cause pain, especially with movement of the shoulder.
Repetitive movements of the arm, particularly those performed overhead, such as swimming, volleyball, and tennis can increase the likelihood of developing SIS. Pain may also develop as the result of minor trauma, such as a fall onto the out-stretched hand or shoulder, or seemingly develop spontaneously with no obvious cause.
Weakness: Decreased shoulder strength. Difficulty with brushing/washing hair.
Decreased Range of Motion: Unable to lift the arm as high either forward or to the side
To diagnose SIS, a doctor will review your symptoms and perform a physical examine. An impingement test, which involves injecting a local anesthetic into the bursa, can help to confirm the diagnosis.
He or she may also request X-rays or a MRI (magnetic resonance imaging) of the shoulder. MRI can show fluid or inflammation in the bursa and rotator cuff. In some cases, partial tearing of the rotator cuff will be seen.
As with other arthritic conditions, initial treatment of arthritis of the shoulder is nonsurgical and may involve physical therapy. In addition, some therapies you may try include:
Resting the shoulder.
A course of non-steroidal anti-inflammatory medications, such as Ibuprofen. Supervised physical therapy and/or home stretching and strengthening exercises. Injection of a local anesthetic and cortisone into the shoulder.
If nonsurgical treatment does not reduce pain, there are surgical options. As with all surgeries, there are some risks and possible complications. Your orthopaedic surgeon will do all that is possible to minimize these risks.
Operations are usually only performed if non-surgical treatment has failed. The goal of surgery is to remove the impingement on the rotator cuff and bursa by creating more space between the humeral head and the acromion.
The most common surgical treatment is sub-acromial decompression. This may be performed by either arthroscopic (small incisions with cameras) or open techniques. In this procedure the portion of the acromion causing impingement is removed along with some of the bursa. The surgeon may also treat other conditions present in the shoulder at the same time, including repairs of any rotator cuff tears.