Impingement Syndrome of The Shoulder

What is impingement syndrome?

Impingement syndrome is a common shoulder condition seen in active adults. This condition is closely related to shoulder bursitis and rotator cuff tendinitis. These conditions may occur alone or in combination.

In most parts of the body, the bones are surrounded by muscles. In the shoulder region, however, the muscle and tendons are surrounded by bone. If one taps on the top of the shoulder, bone can be felt immediately under the skin. Underneath that bone is the rotator cuff, a group of muscles and tendons that we use to lift the arm up overhead. The rotator cuff is sandwiched between the arm bone and the top of the shoulder (acromion). This unique arrangement of muscle and tendon between bone contributes to the development of impingement syndrome (shoulder bursitis, rotator cuff tendinitis).

When an injury to the rotator cuff occurs, it responds by swelling much the way an ankle does when it is sprained. However, because the rotator cuff is surrounded by bone, its swelling causes a number of events to occur. The pressure within the tendon increases, resulting in compression (squeezing) and loss of blood flow in the capillaries (small blood vessels).

When the blood flow is reduced, the tendon tissue begins to fray much like a rope. As the tissue swells, it results in the classic features of a pain like a toothache. Pain is made worse by actions such as reaching up behind the back and reaching up overhead. Pain during the night from this shoulder condition may cause a loss of sleep, and can be a sign of a more serious injury to the rotator cuff, including the development of a small tear or hole in the tendon. This is what is known commonly as a rotator cuff tear.

What are the symptoms of impingement syndrome of the shoulder?

The symptoms of shoulder impingement syndrome include difficulty reaching up behind the back, pain when the arms are extended above the head, and weakness of the shoulder.

In cases of complete tearing of the rotator cuff, patients have very significant weakness and sometimes cannot raise their arm against gravity. In addition, some patients will have a rupture (tear) of their biceps muscle tendon as part of this continuing impingement process.

How is impingement syndrome diagnosed?

The doctor will take the patient's medical history and do a physical examination. X-rays are helpful to rule out arthritis and may show changes in the bone that show the injury of the rotator cuff. There may be bone spurs or changes in the normal contour of the bone where the rotator cuff normally attaches. A diagnosis of impingement syndrome may be made when a small amount of an anesthetic (painkiller) is injected into the space under the acromion and relieves the pain.

How is impingement syndrome of the shoulder treated?

Treatment for impingement syndrome includes ice, over-the-counter anti-inflammatory medications, and an organized physical therapy program.

Ice should be applied to the shoulder for 20 minutes once or twice a day. (A bag of frozen peas or corn also works well for this). If the doctor approves, some patients find that the pain relievers ibuprofen or naproxen are helpful on an as-needed basis. For more severe cases, a stronger prescription strength anti-inflammatory medication may be needed.

The most important treatment for impingement syndrome is physical therapy. In most cases, the patient only needs one visit with the physical therapist to learn how to do physical therapy at home.

A common sense approach to activities is useful. For instance, continuously reaching overhead usually makes shoulders with impingement syndrome worse, and should be avoided. In cases of severe pain, a cortisone injection may be helpful in reducing symptoms. If the patient still has symptoms after all of this treatment, an MRI may be necessary in order to rule out a rotator cuff tear. If the patient does tear his or her rotator cuff, surgery may be necessary.

In summary, impingement syndrome is a common condition in the shoulders of active adults, particularly as they get older. Treatment without surgery usually relieves symptoms. In advanced, long-standing cases, the rotator cuff tendon can tear, in which case the patient may need surgery.