CONDITIONS

Rotator Cuff Injuries

 Four tendons attach muscles from the shoulder blade and ribs to the upper arm bone (humerus). Because these tendons help to rotate the arm within its socket, this sleeve of tendons is called the rotator cuff.

Tendons in the rotator cuff can be injured easily because they move within a tight space. When the shoulder is turned or lifted at the limit of its natural range of movement, the tendons in this tight space are moved, too. Occasionally, the rotator cuff tendons can bump or rub against a bony knob (the acromion) above them or against a ligament at the front of the shoulder.

This friction is known as impingement syndrome and causes inflammation in the rotator cuff. Rotator cuff friction is most likely to cause inflammation if your shoulder movement is rough or repetitive. Inflammation can cause three problems:

• Rotator cuff tendonitis— Inflammation of a single tendon causes pain only during specific movements, when the muscle that pulls against that tendon is being used or when you are reaching upwards.
• Shoulder bursitis, also called subacromial bursitis — Bursitis occurs when inflammation spreads into the pocket of fluid that lubricates the rotator cuff tendons. Pain is often worse at night and occurs when you move your shoulder in almost any direction, particularly if you are reaching upwards.
• Rotator cuff tear— The tendon may tear after it has been weakened by inflammation.Several types of shoulder use commonly trigger rotator cuff injury:

• Pushing off with your arms— People with arthritis of the knee, other painful conditions in the legs, or weak quadriceps muscles in the thighs often compensate by pushing off with their arms when they rise from a chair. The shoulder is not built for this use. During the push off, the shoulder’s socket and humerus function like an upside-down mortar and pestle, crushing and grinding the rotator cuff tendons. Falls onto an outstretched arm, head-on automobile accidents and sports collisions also can crush the tendons.
• Repetitive reaching— Overhead arm positions narrow the tight space that the rotator cuff tendons must pass through. Pushups, pitching a baseball, swimming, house painting, filing, building construction, auto mechanic work and other activities can cause injury of the rotator cuff.
• Forceful or abrupt overhead arm movements— Tears are particularly common in athletes in throwing sports, racquet sports and wrestling. Abrupt movements, such as pulling to start a lawn mower, can tear a weakened tendon.

In addition, your shoulder can be injured more easily if it is out of shape. The narrow space that envelops the rotator cuff tendons becomes even narrower if your shoulder muscles are weakened or tight. When this happens, routine shoulder movements are more likely to cause tendon friction.

Causes

Rotator cuff disease may be the result of either a substantial injury to the shoulder or to progressive degeneration or wear and tear of the tendon tissue. Repetitive overhead activity or heavy lifting over a prolonged period of time may irritate or damage the tendon.

Symptoms

Rotator cuff injuries cause pain in your shoulder and upper arm. The pain may be most noticeable when you reach up or out. When you turn your arm as you lift it, the tendons are more likely to rub against surrounding structures. For this reason your shoulder symptoms may be worst when you try to comb your hair or slip your arm into a sleeve. You also may have dull, aching shoulder pain at night.

Rotator cuff tears that affect a significant portion of the tendon cause weakness of the shoulder, limiting your ability to hold your arm out to one side or to lift an object. Difficulty using the shoulder because of pain does not always mean that there is a tear. Rotator cuff injuries cause pain in your shoulder and upper arm. The pain may be most noticeable when you reach up or out. When you turn your arm as you lift it, the tendons are more likely to rub against surrounding structures. For this reason your shoulder symptoms may be worst when you try to comb your hair or slip your arm into a sleeve. You also may have dull, aching shoulder pain at night.

Rotator cuff tears that affect a significant portion of the tendon cause weakness of the shoulder, limiting your ability to hold your arm out to one side or to lift an object. Difficulty using the shoulder because of pain does not always mean that there is a tear.

Diagnosis

A rotator cuff injury usually is diagnosed by physical examination. Your doctor will rotate your arm at the shoulder and then will raise your arm. If this type of motion causes pain, the rotator cuff may be inflamed.

If you have noticeable weakness, you will need further testing to check for a rotator cuff tear. Your doctor may inject a numbing medicine into your shoulder to help distinguish actual weakness of the tendon from your muscle “giving way” because of pain.

If a tear is suspected, a magnetic resonance imaging (MRI) scan can confirm the diagnosis. An alternative diagnostic test is a shoulder arthrogram. An arthrogram is an X-ray of a joint following injection of dye into the joint. Because MRIs provide excellent pictures without putting a needle into a joint, arthrograms are done less frequently today.

Shoulder X-rays are not always needed, but may be helpful if you have had trauma to the shoulder or if your doctor cannot move your shoulder through its full range of motion. Another reason to do a shoulder X-ray is too look for calcium deposits in or around the shoulder. Calcium deposits form on a persistently inflamed tendon, causing a condition called calcific tendonitis.

Prevention

If you are at risk of rotator cuff injuries or if you’ve had a rotator cuff injury in the past, daily shoulder strengthening exercises can help prevent future injury.

Most people exercise the front muscles of the chest, shoulder and upper arm, but it is equally important to strengthen the muscles in the back of the shoulder and around the shoulder blade to optimize shoulder muscle balance.