Shoulder Pain: The Big Three

“My shoulder hurts, Doc”.  This is a common complaint heard by the orthopedist. The history is remarkably consistent:  gradual onset of increasing shoulder and upper arm pain, with or without a preceding, usually minor, injury.

The diagnosis is most often one of three conditions we`ll call “the Big Three”:  Rotator Cuff Tedinopathy, Adhesive Capsulitis, and Osteoarthritis of the Shoulder. Though similar in presentation, these conditions differ markedly in pathology (what is wrong anatomically and microscopically) and etiology or cause.

• Rotator cuff tendinopathy is a common problem in which shoulder motion, though full, is painful. This pain is worsened when the arm is used away from the body, as in throwing a ball.  The underlying cause of this condition is degenerative: fraying of the cuff’s attachment to bone. This wear and tear phenomenon is not surprising given the stress these short muscle undergo counterbalancing their long lever, the arm.
• Adhesive capsulitis or “frozen shoulder” is characterized by stiffness with marked pain at the extremes of motion. These people cannot reach around to scratch their backs, and throwing off the bed covers in the morning causes severe pain.  The pathology in this entity consists of an inflamed capsule that thickens and undergoes contracture, all of which lead to pain and loss of motion.  The etiology is unknown, but autoimmunity is believed to play a role.
• Osteoarthritis of the shoulder joint is characterized by gradual onset of pain and stiffness with the pain being less intense than the previous two conditions.  Here, the joint surface becomes rough and worn, reducing motion and inducing a dull low grade pain. The origin of osteoarthritis is multifactorial and may include prior trauma or a genetic propensity.

Initial treatment for each of the Big Three is conservative, consisting of physical therapy (stretching, strengthening, education on care of the shoulder for the particular diagnosis), a steroid injection and a measure of time, the latter based on knowledge of the natural history of the particular condition.  In rotator cuff tendinopathy, surgery is considered if conservative therapy fails to bring relief after a few months or initially if there is suspicion that the cuff had been torn by a precipitating injury.  An MRI is almost always used in the surgical decision making.  Frozen shoulder is a self limiting disease, though its protracted course of 6-18 months can try the patience of both doctor and patient.   Steroids injected into the shoulder joint within the first few months of onset can sometimes dramatically reduce pain and shorten the natural course. The shoulder joint afflicted with osteoarthritis often tolerates its burden surprisingly well. A regular program of stretching and strengthening is often all that is needed to maintain reasonable function and a pain level that is tolerable.  For those patients with recalcitrant pain and stiffness, shoulder replacement offers an excellent alternative.

With the possible exception of low back pain, shoulder pain is the most common complaint heard in a general orthopedic practice. Although there are many causes, the vast majority are one of the Big Three, with rotator cuff dysfunction being by far the most common.  Fortunately, in most cases, proper education and rehabilitation can return this complex but fascinating structure we call the shoulder to a high level of function.