Don't shrug off shoulder pain

Since the saga of Atlas, shoulders have figuratively borne the weight of the world. Unfortunately, there is a literal burden, too. Although we tend to take this complex joint for granted, the shoulder is involved in almost every movement of the upper body. So it should come as no surprise that it can hurt. In fact, five percent of all visits to general practitioners are for shoulder troubles.

The shoulder is the joint of all trades: It raises, twists, bends, and moves your arm to the front, back, and sides. As such, it’s the most mobile joint in the body — but the range of motion comes at a cost because the joint is unstable and vulnerable to injury. The good news, however, is that shoulder problems can be avoided, especially if you work to prevent it and are alert to early warnings. If it does develop, it can usually be alleviated with proper treatment.

Shoulder anatomy

The demands on the shoulder are complex — they include a variety of tasks such as combing your hair, swinging a golf club, or simply moving your arms while walking. It has the widest range of motion of any joint in the body. A complex web of tendons and ligaments hold the bones together and account for this mobility. The trade-off is that the shoulder is also one of the body’s most unstable joints and can be affected by several painful conditions.

The shoulder is a ball and socket joint, with the upper arm bone (humerus) nestled into a concave socket that is part of the shoulder blade (scapula). The rotator cuff, a powerful ring of four muscles (the supraspinatus, infraspinatus, teres minor, and subscapularis) and a network of tendons, connects the humerus to the shoulder blade. These muscles are located around the shoulder blade and stabilize the humerus in the shoulder socket while allowing it to have its range of motion (see diagram). The rotator cuff tendons lie between two bones — the head of the humerus and the part of the scapula known as acromion. The subacromial bursa, a fluid-filled sac just beneath the acromion, ordinarily protects the rotator cuff tendons from pressure of the bones on either side. But repetitive stress can compress the bursa, causing the bones to press against the tendons, irritating them and producing rotator cuff tendinitis or subacromial bursitis — two of the most common causes of pain in the shoulder.

Treating the real problem

Although it may seem like pain is coming from your shoulder, the discomfort could be originating from several sources, including a pinched nerve in the neck, a gallbladder problem, or even a tumor on the edge of your lung. Each problem can cause referred pain to your shoulder, which occurs when the area in pain is served by nerves from the same part of the spinal cord as the source of pain. These potential sources should be ruled out prior to any treatment. In addition to a full examination and review of your pain history, your joint may undergo tests, including x-ray, ultrasonography, or MRI.

Rotator cuff tendonitis or tear

Most clinicians diagnose rotator cuff tendonitis by taking a history and performing a physical examination. Your physician will check for tenderness at a point near the top of the upper arm and look for pain as the arm is raised sideways. Your muscle strength and the shoulder’s joint of motion will also be tested. Pain with normal muscle strength suggests rotator cuff tendonitis; pain with weakness may indicate a tear. Surgery usually is not called for, except in those who have actually torn their rotator cuff. If surgery is in order, arthroscopic techniques sometimes are sufficient. Such procedures utilize a miniature camera called an arthroscope to examine the joint; necessary repairs are made through a tiny incision. More severe injury may require a larger incision to repair a torn tendon.

The minimum time for recovery from acute rotator cuff tendonitis is two to four weeks, and stubborn cases can take several months. Early on, the aim is to reduce swelling and inflammation of the tendons and relieve compression in the subacromial space. Later, exercises can be started to strengthen the muscles and improve range of motion (see diagram). During the first few days, apply an ice pack to the shoulder for 15 to 20 minutes every four to six hours. If you still have a lot of pain, take a nonsteroidal anti-inflammatory drug (NSAID), such as ibuprofen. Your physician may also suggest a corticosteroid injection, but there’s no clear evidence that this offers any advantage in the long term over physical therapy and NSAID use.

While you’re in pain, avoid lifting or reaching out, up, or overhead as much as possible. On the other hand, you don’t want to stop moving your shoulder altogether, because that can lead to a “frozen shoulder,” a condition in which the tissues around the shoulder shrink and reduce its range of motion.

Frozen shoulder

Everyone knows that if you don’t use a mechanical device for a long time, it doesn’t always work right when you start it up again. The same can be true of your shoulder. When you avoid using it (for good reasons like tendonitis, surgery that immobilizes the arm or shoulder, or an injury to the lower arm), you leave yourself open to pain and limitation of your shoulder’s range of motion — a condition called frozen shoulder, or adhesive capsulitis.

Although doctors know that underuse of the shoulder is a common denominator in all occurrences of frozen shoulder, what initiates it is still a mystery. Rarely, the patient will have suffered trauma to the shoulder joint itself, but most cases seem to be spontaneous. Doctors do know that postmenopausal women holding sedentary jobs are at the highest risk, and that the shoulder opposite the hand you use most is usually the one affected. Those with diabetes mellitus also have a higher than average risk of frozen shoulder.

An occurrence of frozen shoulder usually begins with a stiffness that is increasingly accompanied by pain whenever the limits of shoulder movement are reached. Sleeping on the affected side becomes difficult. This can last from two to nine months. Eventually, the pain levels off, but the stiffness continues for four to twelve months. A “thawing” of the joint takes place over a final stage of five to 26 months. However, the thawing is occasionally incomplete and some limitation remains, although this often goes unnoticed.

How motion is limited. What happens inside the shoulder is that the joint capsule wrapped around the end of the humerus nearest to the shoulder, and the membrane lining the gap between the humerus and the shoulder, become inflamed, causing adhesions, or attachments, to develop. These adhesions cause pain and restrict mobility by tightening the capsule around the humerus.

Getting the shoulder moving. All treatment begins with gentle stretching exercises prescribed by a doctor and done by physical therapists. This is definitely a case of “easy does it.” Too vigorous an exercise program will only aggravate the pain, with no gain in mobility. The opposite is also true: Underuse is what started the trouble in the first place, so resting the arm in a sling will only make it worse. Corticosteroid injections into the joint can help relieve the pain, though not with everyone. Application of cold or heat over and under the shoulder may also help. You should keep in mind that exercise will have no immediate effect: It takes several weeks before any benefit is felt.

If, after that time, there is no response to the exercises, your physician might suggest manipulation of the shoulder under general anesthesia. The surgical option, which is rarely resorted to, consists of probing into the joint and physically separating the adhesions.

If you feel your shoulder getting stiff over the period of a few weeks, ask your doctor about it. Many other causes of shoulder pain will first have to be ruled out (for example, tendonitis from an injury), but in freeing up a frozen shoulder, an early start of therapy gives you the best chance for shortening its duration by restoring mobility and reducing pain.