Shoulder Impingement

What is Shoulder Impingement?

Impingement refers to mechanical compression and/or wear of the rotator cuff tendons. The rotator cuff is actually a series of four muscles connecting the scapula (shoulder blade) to the humeral head (upper part of the shoulder joint.) The rotator cuff is important in maintaining the humeral head within the glenoid (socket) during normal shoulder function and also contributes to shoulder strength during activity. Normally, the rotator cuff glides smoothly in a bony tunnel the ceiling of which is the undersurface of the acromion and the floor, the humeral head. This space is lined with a bursa which insures tendon sliding against the bony walls.

How Does Shoulder Impingement Occur?

Any process which compromises this normal gliding function may lead to mechanical impingement. Common causes include weakening and degeneration within the tendon due to aging, the formation of bone spurs and/or inflammatory tissue within the space above the rotator cuff (subacromial space), and overuse injuries. This results in a narrowing of the bony tunnel mostly from the ceiling. Overuse activities can lead to impingement and are most seen in tennis players, pitchers, and swimmers.

Overhead activity

How is Shoulder Impingement Diagnosed?

The diagnosis of shoulder impingement can usually be made with a careful history and physical exam. Patients with impingement most commonly complain of pain in the shoulder, which is worse with overhead activity and some-times severe enough to cause awakening in the night. Manipulation of the shoulder in a specific way by your doc-tor will usually reproduce the symptoms and confirm the diagnosis. X-rays are also helpful in evaluating the presence of bone spurs and/or the narrowing of the subacromial space. Ultrasounds and/or MRI (magnetic resonance imaging) allow visualization of the rotator cuff and assess its status: inflammation, partial tear, and acromio-clavicular joint bulging. 

How is Shoulder Impingement Treated?

The first step in treating shoulder impingement is eliminating any identifiable cause or contributing factor. This may mean temporarily avoiding activities like tennis, pitching or swimming. A non-steroidal anti-inflammatory medication may also be recommended by your doctor. The mainstay of treatment involves exercises to restore normal flexibility and strength to the shoulder girdle, including strengthening both the rotator cuff muscles and the muscles responsible for normal movement of the shoulder blade. This program of instruction and exercise demonstration may be initiated and carried out either by the doctor, certified athletic trainer, or a skilled physical therapist. Occasionally, an injection of cortisone or PRP may be helpful in treating this condition, followed by rehabilitation. 

Is Surgery Necessary?

Surgery is not necessary in most cases of shoulder impingement. But if symptoms persist despite adequate non-surgical treatment, surgical intervention may be beneficial. Surgery involves debriding, or surgically removing tissue that is irritating the rotator cuff. It is a daycare procedure done under arthroscopic techniques, the “keyhole” surgery. It is followed by rehabilitation sessions. Outcome is favorable in about 90% of the cases.