Rotator Cuff Disease - An Overview

1. Overview
2. Diagnosis
3. Treatment and Recovery
4. Calcium Deposits-Another Type of Rotator Cuff Disease

As the primary cause of shoulder pain in Americans, rotator cuff disease constitutes a common and highly treatable disorder. This diagnosis actually refers to a spectrum of injuries that can affect the rotator cuff-the complex of muscles and tendons that provide stability to the shoulder joint-ranging from irritation and inflammation to a complete tear of any one or more of three tendons: the supraspinatus, the infraspinatus, and the subscapularis. (A fourth tendon, the teres minor, also helps form this complex, but is seldom subject to injury.)

Anatomy of the shoulder

Injury to the rotator cuff may occur either as a result of a gradual wearing process, or as the result of trauma-for example, an injury incurred during athletic activity or in a motor vehicle accident.

To better understand the rotator cuff's vulnerability, it's helpful to consider the anatomy of the shoulder. As noted, the rotator cuff provides stability, specifically, to the ball-and-socket joint of the shoulder, also called the gleno-humeral joint. Depending on the direction that the joint is moved in, stress is placed on the various muscle-tendon pairs in the cuff. The portion of the cuff that is the most prone to injury is the supraspinatus, which must pass under the shoulder cap or acromion-through a small area that is called the subacromial space. (See image above.)

"Anything that takes up space in the subacromial space can lead to problems," explains Edward V. Craig, an attending orthopaedic surgeon at HSS. Causes of rotator cuff disease can include:

• Tendinitis: inflammation and swelling of the tendons
• Bursitis: inflammation and swelling of the bursa (a fluid-filled sac that provides cushioning in the subacromial space and facilitates tendon gliding)
• Development of an osteophyte (a bone spur) projecting down from the acromion or clavicle that overlies the tendon. This occurs with osteoarthritis in the AC joint-where the acromion meets the clavicle (collar bone). As cartilage wears away, bone spurs tend to occur
• Some patients have an anatomical variation resulting in a curved, more prominent projection of the front edge of the acromion that contributes to the development of impingement

As the subacromial space becomes tighter, the tendon is pinched, and a syndrome of impingement may be diagnosed. Thereafter, a destructive cycle may begin, in which the bone rubs against the tendon, the tendon becomes more irritated and swollen, and thus more pinched. Eventually, the tendon may become frayed.

"It's not unlike what happens with a rope swing," says Dr. Craig. "Just as the rope that holds up a swing may begin to fray as the result of friction by the branch, in the same way, the supraspinatus portion of the rotator cuff tendon rubs under the edge of the acromion." This fraying represents a partial tear of the tendon.

Partial Tear

If the process continues unchecked, the tendon, which has become weakened but still must bear the same stresses, may develop a full tear. A full or complete tear is when the damage is through the entire thickness of the tendon. This produces a gap in the tendon which is increased by the tension in the adjacent muscle.

Complete tendon discontinuity

If a complete tear develops in one tendon (usually the supraspinatus), the other rotator cuff tendons become more likely to fail, as they are subjected to greater tension, much as a hole in a carpet gets larger as it continues to be walked on. The age of the individual can also contribute to the progress of rotator cuff disease, with older tendons not only less able to withstand damaging friction but also less likely to heal after minor injury. In addition to gradually accruing damage and injuries from acute trauma, orthopaedic surgeons like Dr. Craig see another kind of rotator cuff injury specific to vigorous shoulder exercise, particularly in throwing athletes, such as baseball pitchers. These problems begin with the ligaments in the shoulder becoming stretched and loose from overuse. This in turn allows the shoulder a greater range of translation in the socket, a condition called shoulder instability. (For more information on shoulder instability, please see the link at the conclusion of this article.) Instability puts greater pressure and tension on the rotator cuff and can result in impingement and partial or complete tears.

Diagnosis

Whether a patient has a simple case of tendonitis or a rotator cuff tear, the symptoms may be the same, that is, generalized shoulder pain and tenderness. In some cases, patients do not seek medical attention until they notice muscle weakness, a sign that the condition is progressing.

Orthopaedic surgeons use a variety of means to diagnose rotator cuff disease, including patient history, physical examination, x-rays (which help rule out other conditions or detect co-existing injury), and MRI or ultrasound technology, which can provide detailed images of the rotator cuff. At HSS, highly sophisticated MRI techniques and experienced staff are able to detect even very small tears, according to Dr. Craig.

The orthopaedic surgeon may also use a diagnostic injection to help localize the area of injury. A small amount of novocaine is injected into a specific area of the shoulder joint in order to pinpoint the source of the pain. If an injection that numbs the top surface of the tendon allows the patient to raise his or her arm without pain, rotator cuff disease is the likely disorder.

Treatment and Recovery

Many patients with tendinitis or a partial tear are able to heal without surgical intervention. Treatment usually includes anti-inflammatory medication, physical therapy exercises, activity modification, and rest. A steroid injection may also be administered to reduce inflammation.

When surgical treatment is deemed necessary-either because of the extent of the injury-or when non-surgical treatment fails, a range of procedures may be considered.

In patients with bursitis and tendonitis caused by rubbing against the shoulder cap (the acromion), the surgeon may address the problem by excising the thickened bursa sac and/or by performing an acromioplasty (shaving away some of the acromion), thus opening up the space for the injured tendon. At HSS this procedure, called subacromial decompression, is almost always done arthroscopically under regional anesthesia. (For more information on shoulder arthroscopy, please see the link at the conclusion of this article.)

"Based on our experience, those patients with a tear of less than 50% of the tendon thickness usually do well when we shave the bone down and smooth the tendon," says Dr. Craig. "When the tear is greater than 50%, the tendon is unlikely to heal on its own." In such cases, the orthopaedic surgeon must not only open up the space around the tendon to address the cause of disease, but also sutures the torn edge of the tendon back to the humerus bone.

Rotator cuff repair was originally performed using an "all open" technique, in which both the bony "decompression" and the tendon "repair" were performed through a skin incision, with detachment and repair of the outer muscle layer. This associated trauma to the surrounding tissues was frequently associated with a greater degree of post- operative pain and long rehabilitation. A "mini-incision" technique followed, in which the orthopaedic surgeon used an arthroscope to visualize the inside of the shoulder, with the bony decompression being performed arthroscopically and the tendon repair being performed through a small incision which did not damage associated muscles. Today, many HSS surgeons are able to perform the entire operation, both bony decompression and tendon repair, arthroscopically.

Arthroscopic photos showing a tendon being sutured to bone

As might be expected, recovery from surgical treatment of rotator cuff disease varies with the procedure used. For all patients, pain relief and restoration of motion, strength, and function are primary goals. Individuals who have had tendon suturing must protect the repair until the tendon has securely healed to the bone-a period of about six to eight weeks. In the interim, a program of passive and active assisted motion exercises is prescribed, with close supervision by a physical therapist, in order to avoid tension on the repaired tendon while motion is being restored. Muscle strengthening exercises follow.

Most patients experience significant pain relief within a week or two of surgery. However, because it takes considerable rehabilitation of the shoulder muscles to restore the strength and endurance of the shoulder, return to normal function may take six months or longer. "Using these criteria, our success rate is at least 95%," says Dr. Craig. While pain relief has been quite predictable, return of strength is somewhat more variable and depends on several factors which may be beyond surgeon, therapist, and patient control such as how long the tear has been present; how big it is; how much muscle atrophy has occurred; the condition of the tendon; how well the patient protects the cuff following surgery; and the patient's commitment to post-operative exercises. "Overall, smaller tears do better than large ones," Dr. Craig notes.

Calcium Deposits-Another Type of Rotator Cuff Disease

Some patients with rotator cuff injury may develop calcific tendonitis. In these individuals, calcium deposits build up in the damaged tendon tissue causing pressure and pain. Often, the underlying cause is overuse. "There is a characteristic scenario with this condition," says Dr. Craig. "Patients come in holding the arm to the side to avoid movement. They may have spent a weekend doing carpentry or painting ceilings, and then are awakened on a Sunday night with incapacitating pain."

Fortunately, most calcium deposits are visible on x-ray, and can be treated by removing the calcium, either with a needle as a Radiology procedure or via arthroscopy as an outpatient surgical procedure, depending on the size of the calcium deposit and how long it has been there. "Moreover", says Dr. Craig, "Pain relief is immediate and these conditions are usually not recurrent. Once the calcium deposit is removed, it won't come back." Patients with calcium deposits can also take comfort in the fact that this condition does not appear to predispose them to further rotator cuff disease.