The term rotor" cuff, actually- the rotator cuff- refers to a group of muscles and associated tendons that connect the scapula (shoulder blade) to the humerus (upper arm bone). The rotator cuff tendons sit on top of the humerus and permit movement in all directions. In fact, the shoulder is the most mobile joint in the body. Because of the wide range of motion that the shoulder joint has... plus the amount of work that the shoulder has to do doing activities of daily living, the rotator cuff becomes prone to overuse and injury. Excessive stress on the rotator cuff leads to shoulder pain.

Rotator cuff injury is fairly common and can be due to repetitive stress, trauma, and aging.

Repetitive stress can be occupational- people who do work with the arms raised above the level of the shoulder- can develop shoulder problems easily. Examples would be auto mechanics, dry wall installers, house painters, and electricians.

Sports activities such as golf, tennis, softball, and other athletic endeavors that require repeated shoulder movement can also be a problem.

Trauma, particularly falls are a common cause of rotator cuff injury.

As people get older, the tendons that comprise the rotator cuff become more prone to injury and degeneration. The tendons of the rotator cuff are made of tough fibrous connective tissue similar to connective tissue located elsewhere in the body. Examples of connective tissue include ligaments, tendons, and cartilage. Connective tissue tends to degrade with age. Combining repetitive use with the aging process is a recipe for significant rotator cuff injury.

Injuries to the rotator cuff usually are due to inflammation. This is called tendonitis or tendonopathy.

More serious injuries result in partial tearing of the tendons. Even more serious is a "full-thickness" or complete tear. While there are many causes of rotator cuff injury, the most common is when the rotator cuff tendons are squeezed between the humerus and the scapula. This squeezing occurs when the arm is raised above the level of the shoulder.

Symptoms of rotator cuff related malfunction usually are pain related. Pain at night is very common and is caused by inflammation in the both the tendons as well as the adjacent bursa. This bursa- called the subacromial bursa- is a sack that contains a small amount of fluid and cushions the shoulder. When it becomes inflamed, the condition is called bursitis. Muscle spasm may also contribute to the pain. Pain is most intense at night.

The pain may radiate down the side of the upper arm. This is called referred pain.

Rotator cuff problems are diagnosed by taking a careful history and doing a thorough physical examination.

Plain x-rays are of limited usefulness unless the patient also has concomitant arthritis. An MRI is probably the most accurate method for imaging the entire shoulder including the soft tissues, tendons, and bone. Diagnostic ultrasound is another less expensive technology which is probably as effective for visualizing the rotator cuff.

Partial tears can be treated with anti-inflammatory medication and physical therapy. In patients with more severe pain or who do not respond to conservative measures, injection of glucocorticoid (cortisone) can be effective. Injections should be done using ultrasound needle guidance. Otherwise, the injection may not be done in the proper location.

Larger rotator cuff tears generally don't heal without intervention. Depending on the age of the patient, length of duration of the tear, size of the tear, and the patient's other medical problems, surgery may be a solution. In cases where more conservative measures fail to provide relief from pain and improved function, surgery is also an option.

Most rotator cuff surgery is performed arthroscopically using small incisions for the insertion of a tiny camera and surgical cutting instruments.

As mentioned earlier, multiple factors go into deciding whether a patient is a good surgical candidate. Other factors determine prognosis. Factors that can influence healing include the size of the tear, the number of tendons that are torn, smoking and patient age.

Physical therapy following surgery is essential to restore full mobility and to protect the surgical repair. This may be arduous, taking several weeks before function is restored adequately.

For prevention of rotator cuff tears, it is good practice to consult a knowledgeable physical therapist who can teach specific exercises.

Warming up and stretching before activities is recommended. Patients should avoid exercises that place the arm at extreme positions, that involve lifting a large amount of weight, or which involve repetitive motion particularly with the arms higher than shoulder level.