Shoulder pain is caused by a number of different conditions, many of these are multifactorial and some are related to underlying pathologies. Shoulder pain in the United States is surpassed only by knee pain and low-back pain in its degree of frequency.

The shoulder is a complex joint comprised of 30 muscles. Factors that may contribute to shoulder pain includes inflammatory conditions, repetitive motion, muscle weakness or imbalance, trauma or simple daily use.

There three main locations where shoulder pain generally occurs. These three areas are the glenohumeral joint where the ball of the arm bone creates a joint with the socket, the acromioclavicular joint, where the collar bone creates a joint with the acromion (roof bone) of the shoulder, and the subacromial space where the rotator cuff and bursa exists.

One of the most common problems is shoulder impingment. This occurs in the subacromial space. This condition can be caused by weakness in the rotator cuff. When the rotator cuff is weak, it allows the arm bone and the attached rotator cuff to drift upward pinching the bursa between the roof bone of the shoulder and the rotator cuff. This can create difficulty reaching overhead and lifting with the outstretched arm. Many times this problem can be corrected with physical therapy and occasionally a corticosteroid injection (commonly known as cortisone) into the area to decrease the inflammation of the bursa.

A second issue that can create bursitis and impingement syndrome is arthritis of the AC joint. This can occasionally develop large spurs that point downward and irritate these tissues. The treatment includes physical therapy, injection and, if needed, surgery to remove the spurs. Commonly, AC joint arthritis can create pain even if this is not directly irritating the underlying tissues. This arthritis pain can make it painful to reach across in front of you. The pain can affect simple everyday activities like putting on a seatbelt, opening doors and can cause restless sleep. Isolated AC joint arthritis can also be treated with corticosteroid injections if simple anti-inflammatory medicines fail to help. For pain that does not respond to conservative treatment, surgery can be performed. The surgery involves removing a small amount of bone at the AC joint so the bones do not rub together any longer. This is called an distal clavical resection.

Degenerative arthritis of the glenohumeral joint is a common issue causing pain. There are a number of structures involved but this is basically wearing away of the cartilage on the surface of the ball and socket which creates the shoulder joint. This can gradually cause a decrease in the ability to move the arm normally and can cause nighttime pain. In severe cases this becomes a constant nagging pain. Glenohumeral arthiritis is initially treated with anti-inflammatory medicines and corticosteroid injections . When conservative treatment is exhausted there are two different types of shoulder replacements available. One is a standard shoulder replacement that replicates the body’s normal anatomy. This involves a stem in the arm bone with an attached metal ball that articulates with a plastic socket. A second type recommended for older patients and those without an intact rotator cuff is called a reverse shoulder replacement. This involves the same type of stem in the arm bone, but the socket portion of the replacement is on the opposite side, with the ball portion on the socket side. This type of replacement eliminates the need for a fully functional rotator cuff.

The last of these common problems seen in a clinical setting is rotator cuff tendinitis or tear. A rotator cuff tear is usually caused by a fall, hard pulling or pushing, repetitive activity or wearing away because of poor posture, a weak rotator cuff or tearing caused by an AC spur. If left untreated a chronic tear can lead to muscular atrophy, eventual glenohumeral arthirits and a poorly functional shoulder. Any persistent weakness or pain in the arm should be evaluated by an orthopedist. An orthopedic provider can determine if your injury can be treated conservatively or requires advanced imaging such as an MRI to further identify the extent of a possible tear.

These tears can be treated with physical therapy and anti-inflammatory medicine if very small. Larger tears can be treated surgically with a rotator cuff repair. This requires extensive post operative physical therapy and monitoring by your orthopedic provider. Most rotator cuff repairs will return the average patient to about 85 percent to 100 percent of their normal pre-injury function. More athletic and younger individuals tend to have better post operative results.

 

Dr. Jeff Barwick is an orthopedic surgeon at Vidant Orthopedics Washington, 1207 Highland Drive.