Oh, My Aching Shoulder
Suresh Velagapudi, M.D.

The shoulder is a remarkable joint—allowing motion in multiple direction while at the same time maintaining stability so that it does not dislocate. A complex of ligaments and tendons function in concert to achieve this marvelous balance between motion and stability. The shoulder is technically a ball-and-socket joint with the ball at the top of the bone of the upper arm (the humerus) and a flat socket that is shaped more like a shallow saucer than a cup. The ligaments are leather-like cords that connect bone (ball) to bone (socket) and are primarily responsible for keeping the joint from dislocating. A tendon, on the other hand, is the end of a muscle that attaches to a bone. When a muscle contracts it pulls on its tendon, which pulls on the bone, which then moves. In the shoulder there are four main muscle-tendon units that direct the motion of the ball as it rotates on the socket, and together they are called the rotator cuff.

These four tendons pass through a small slit-like space with just enough clearance so that they do not rub on the bones above or below them. A bursa, a small fluid-filled sac, cushions them from rubbing on those bones. Excessive motion, abnormally mechanics or injury can cause swelling and inflammation of the burse or the tendons resulting in bursitis or rotator cuff tendonitis. Once there is swelling in the bursa or in the tendons, there is often not enough clearance between the bones so that each time the shoulder is moved in certain directions the bursa or the tendons are rubbed or punched between the bones—and that is called impingement. Impingement most often is the result of repetitive motion at the shoulder such as throwing, swimming, serving in tennis or working overhead. Individuals with impingement usually first experience pain when moving the arm out to the side away from the body or reaching overhead. The pain is usually felt on the side of the upper arm just below the shoulder.

Evaluation of a patient with impingement begins with obtaining a history from the patient in an effort to identify activities that might irritate the rotator cuff tendons or bursa. Physical examination will determine areas of tenderness, limitations of motion or weakness of muscles. X-rays might be done to look for evidence of arthritis or calcium deposits that might irritate the bursa or the tendons. MRI can be used to assess the condition of the bursa used to assess the condition of the bursa and tendons or to look for an advanced problem such as rotator cuff tear.

The treatment of impingement in its early stages is directed toward reducing and ultimately eliminating the swelling and inflammation of the bursa and/or tendons. Such treatment may take the form of first eliminating or modifying the activities that repeatedly cause those structures to be punched. Additionally, anti-inflammatory medication is usually used to reduce the inflammation (ultrasound, for instance) and to strengthen weak muscles, so that the four muscles of the rotator cuff can work smoothly in balance with on another. After all, if one of the four rotator cuff muscles is weak, the others will naturally try to compensate for that weakness, which will result in the other muscles being strained excessively and causing further inflammation and swelling. Cortisone injection into the shoulder might be used to reduce the swelling and inflammation if all else fails. If the treatment is successful then one can anticipate a return to full activity—perhaps with some modification in shoulder mechanics to prevent a recurrence.

If the initial treatment (which can often last for a few months) is not successful or if the rotator cuff problem is of long standing then it may not be possible to reduce the swelling in the tissues to a point where they will not continually be impinged with activity. In that case treatment might be directed to enlarging the slit-like space that the tendons run through so that they are not continually rubbed as the shoulder is moved. That process, which involves grinding away a little bone to make the space wider, can usually be accomplished with outpatient arthroscopic surgery, The recovery from such surgery is usually fairly rapid and, after giving the tendon time to return to normal and then completing a rehabilitation program to restore strength to weak muscles, a return to normal activities can once again be anticipated.

If impingement has existed for a long period of time the tendon can degenerate, fray and ultimately develop a tear (much like wearing out the sole of one’s shoe). It may begin small by will likely get larger with time and the continued use of the shoulder. Depending on the patient’s age, the physical demands to which the shoulder will be subjected and the response to conservative treatment, surgery to repair the tear may well be recommended at this stage. Though recovery is longer after a tear is repaired, return to normal activity is once again the anticipated goal.

There is a wide spectrum of problems that can affect the rotator cuff tendons of the shoulder. However, accurate diagnosis and prompt, effective treatment can be expected to result in a return to normal function for the majority of patients.

top of page