Questions and Answers about Shoulder Problems
What Are the Most Common Shoulder Problems?
The most movable joint in the body, the shoulder is also one of the most potentially unstable joints. As a result, it is the site of many common problems. They include sprains, strains, dislocations, separations, tendinitis, bursitis, torn rotator cuffs, frozen shoulder, fractures, and arthritis. Specific shoulder problems will be discussed later in this publication.
What Are the Structures of the Shoulder and How Does It Function?
To better understand shoulder problems and how they occur, it helps to begin with an explanation of the shoulder’s structure and how it functions.
The shoulder joint is composed of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) (see illustration). Two joints facilitate shoulder movement. The acromioclavicular (ah-KRO-me-o-klah-VIK-u-lahr or AC) joint is located between the acromion (ah-KRO-me-on, the part of the scapula that forms the highest point of the shoulder) and the clavicle. The glenohumeral joint, commonly called the shoulder joint, is a ball-and-socket-type joint that helps move the shoulder forward and backward and allows the arm to rotate in a circular fashion or hinge out and up away from the body. (The “ball,” or humerus, is the top, rounded portion of the upper arm bone; the “socket,” or glenoid, is a dish-shaped part of the outer edge of the scapula into which the ball fits.) The capsule is a soft tissue envelope that encircles the glenohumeral joint. It is lined by a thin, smooth synovial membrane.
In contrast to the hip joint, which more closely approximates a true ball-and-socket joint, the shoulder joint can be compared to a golf ball and tee, in which the ball can easily slip off the flat tee. Because the bones provide little inherent stability to the shoulder joint, it is highly dependent on surrounding soft tissues such as capsule ligaments and the muscles surrounding the rotator cuff to hold the ball in place. Whereas the hip joint is inherently quite stable because of the encircling bony anatomy, it also is relatively immobile. The shoulder, on the other hand, is relatively unstable but highly mobile, allowing an individual to place the hand in numerous positions. It is, in fact, one of the most mobile joints in the human body.
The bones of the shoulder are held in place by muscles, tendons, and ligaments. Tendons are tough cords of tissue that attach the shoulder muscles to bone and assist the muscles in moving the shoulder. Ligaments attach shoulder bones to each other, providing stability. For example, the front of the joint capsule is anchored by three glenohumeral ligaments. The rotator cuff is a structure composed of tendons that work along with associated muscles to hold the ball at the top of the humerus in the glenoid socket and provide mobility and strength to the shoulder joint. Two filmy sac-like structures called bursae permit smooth gliding between bones, muscles, and tendons. They cushion and protect the rotator cuff from the bony arch of the acromion.
The shoulder is easily injured because the ball of the upper arm is larger than the shoulder socket that holds it. To remain stable, the shoulder must be anchored by its muscles, tendons, and ligaments.
Although the shoulder is easily injured during sporting activities and manual labor, the primary source of shoulder problems appears to be the natural age-related degeneration of the surrounding soft tissues such as those found in the rotator cuff. The incidence of rotator cuff problems rises dramatically as a function of age and is generally seen among individuals who are more than 60 years old. Often, the dominant and nondominant arm will be affected to a similar degree. Overuse of the shoulder can lead to more rapid age-related deterioration.
Shoulder pain may be localized or may be felt in areas around the shoulder or down the arm. Disease within the body (such as gallbladder, liver, or heart disease, or disease of the cervical spine of the neck) also may generate pain that travels along nerves to the shoulder. However, these other causes of shoulder pain are beyond the scope of this publication, which will focus on problems within the shoulder itself.
As with any medical issue, a shoulder problem is generally diagnosed using a three-part process.
Other diagnostic tests, such as one that involves injecting an anesthetic into and around the shoulder joint, are discussed in detail in other parts of this publication.
The symptoms of shoulder problems, as well as their diagnosis and treatment, vary widely, depending on the specific problem. The following is important information to know about some of the most common shoulder problems.
The shoulder joint is the most frequently dislocated major joint of the body. In a typical case of a dislocated shoulder, either a strong force pulls the shoulder outward (abduction) or extreme rotation of the joint pops the ball of the humerus out of the shoulder socket. Dislocation commonly occurs when there is a backward pull on the arm that either catches the muscles unprepared to resist or overwhelms the muscles. When a shoulder dislocates frequently, the condition is referred to as shoulder instability. A partial dislocation in which the upper arm bone is partially in and partially out of the socket is called a subluxation.
After treatment and recovery, a previously dislocated shoulder may remain more susceptible to reinjury, especially in young, active individuals. Ligaments may have been stretched or torn, and the shoulder may tend to dislocate again. A shoulder that dislocates severely or often, injuring surrounding tissues or nerves, usually requires surgical repair to tighten stretched ligaments or reattach torn ones.
Sometimes the doctor performs surgery through a tiny incision into which a small scope (arthroscope) is inserted to observe the inside of the joint. After this procedure, called arthroscopic surgery, the shoulder is generally stabilized for about 6 weeks. Full recovery takes several months. In other cases, the doctor may repair the dislocation using a traditional open surgery approach.
A shoulder separation occurs where the collarbone (clavicle) meets the shoulder blade (scapula). When ligaments that hold the joint together are partially or completely torn, the outer end of the clavicle may slip out of place, preventing it from properly meeting the scapula. Most often, the injury is caused by a blow to the shoulder or by falling on an outstretched hand.
These conditions are closely related and may occur alone or in combination.
Tendinitis is inflammation (redness, soreness, and swelling) of a tendon. In tendinitis of the shoulder, the rotator cuff and/or biceps tendon become inflamed, usually as a result of being pinched by surrounding structures. The injury may vary from mild inflammation to involvement of most of the rotator cuff. When the rotator cuff tendon becomes inflamed and thickened, it may get trapped under the acromion. Squeezing of the rotator cuff is called impingement syndrome.
Bursitis, or inflammation of the bursa sacs that protect the shoulder, may accompany tendinitis and impingement syndrome. Inflammation caused by a disease such as rheumatoid arthritis may cause rotator cuff tendinitis and bursitis. Sports involving overuse of the shoulder and occupations requiring frequent overhead reaching are other potential causes of irritation to the rotator cuff or bursa and may lead to inflammation and impingement.
If the rotator cuff and bursa are irritated, inflamed, and swollen, they may become squeezed between the head of the humerus and the acromion. Repeated motion involving the arms, or the effects of the aging process on shoulder movement over many years, may also irritate and wear down the tendons, muscles, and surrounding structures.
Rotator cuff tendons often become inflamed from overuse, aging, or a fall on an outstretched hand or another traumatic cause. Sports or occupations requiring repetitive overhead motion or heavy lifting can also place a significant strain on rotator cuff muscles and tendons. Over time, as a function of aging, tendons become weaker and degenerate. Eventually, this degeneration can lead to complete tears of both muscles and tendons. These tears are surprisingly common. In fact, a tear of the rotator cuff is not necessarily an abnormal situation in older individuals if there is no significant pain or disability. Fortunately, these tears do not lead to any pain or disability in most people. However, some individuals can develop very significant pain as a result of these tears and they may require treatment.
Treatment for a torn rotator cuff usually depends on the severity of the injury, the age and health status of the patient, and the length of time a given patient may have had the condition. Patients with rotator cuff tendinitis or bursitis that does not include a complete tear of the tendon can usually be treated without surgery. Nonsurgical treatments include the use of anti-inflammatory medication and occasional steroid injections into the area of the inflamed rotator cuff, followed by rehabilitative rotator cuff-strengthening exercises. These treatments are best undertaken with the guidance of a health care professional such as a physical therapist, who works in conjunction with the treating physician.
Surgical repair of rotator cuff tears is best for the following individuals.
Generally speaking, individuals who are older and have had shoulder pain for a longer period of time can be treated with nonoperative measures even in the presence of a complete rotator cuff tear. These people are often treated similarly to those who have pain but do not have a rotator cuff tear. Again, anti-inflammatory medication, use of steroid injections, and rehabilitative exercises can be very effective. When treated surgically, rotator cuff tears can be repaired by either arthroscopic or traditional open surgical techniques.
As the name implies, movement of the shoulder is severely restricted in people with a “frozen shoulder.” This condition, which doctors call adhesive capsulitis, is frequently caused by injury that leads to lack of use due to pain. Rheumatic disease progression and recent shoulder surgery can also cause frozen shoulder. Intermittent periods of use may cause inflammation. Adhesions (abnormal bands of tissue) grow between the joint surfaces, restricting motion. There is also a lack of synovial fluid, which normally lubricates the gap between the arm bone and socket to help the shoulder joint move. It is this restricted space between the capsule and ball of the humerus that distinguishes adhesive capsulitis from a less complicated painful, stiff shoulder. People with diabetes, stroke, lung disease, rheumatoid arthritis, and heart disease, or those who have been in an accident, are at a higher risk for frozen shoulder. People between the ages of 40 and 70 are most likely to experience it.
A fracture involves a partial or total crack through a bone. The break in a bone usually occurs as a result of an impact injury, such as a fall or blow to the shoulder. A fracture usually involves the clavicle or the neck (area below the ball) of the humerus.
Fracture of the neck of the humerus is usually treated with a sling or shoulder stabilizer. If the bones are out of position, surgery may be necessary to reset them. Exercises are also part of restoring shoulder strength and motion.
Arthritis is a degenerative disease caused by either wear and tear of the cartilage (osteoarthritis) or an inflammation (rheumatoid arthritis) of one or more joints. Arthritis not only affects joints, but may also affect supporting structures such as muscles, tendons, and ligaments.
When nonoperative treatment of arthritis of the shoulder fails to relieve pain or improve function, or when there is severe wear and tear of the joint causing parts to loosen and move out of place, shoulder joint replacement (arthroplasty) may provide better results. In this operation, a surgeon replaces the shoulder joint with an artificial ball for the top of the humerus and a cap (glenoid) for the scapula. Passive shoulder exercises (where someone else moves the arm to rotate the shoulder joint) are started soon after surgery. Patients begin exercising on their own about 3 to 6 weeks after surgery. Eventually, stretching and strengthening exercises become a major part of the rehabilitation program. The success of the operation often depends on the condition of rotator cuff muscles before surgery and the degree to which the patient follows the exercise program.
If you injure a shoulder, try the following:
Rest. Reduce or stop using the injured area for 48 hours.
Ice. Put an ice pack on the injured area for 20 minutes at a time, 4 to 8 times per day. Use a cold pack, ice bag, or a plastic bag filled with crushed ice that has been wrapped in a towel.
Compression. Compress the area with bandages, such as an elastic wrap, to help stabilize the shoulder. This may help reduce the swelling.
Elevation. Keep the injured area elevated above the level of the heart. Use a pillow to help elevate the injury.
If pain and stiffness persist, schedeule an appointment.