For many years, the terms adhesive capsulitis and frozen shoulder were used to describe the same condition. Patients experience shoulder pain and loss of shoulder motion. The problem comes on slowly over a period of time and seems to affect women more often than men (especially women between the ages of 40 and 60).
But experts recognize now that there are many different shoulder conditions that can present with these (or similar) symptoms. So the old term “frozen shoulder”, once used to describe any painful, stiff shoulder is now more refined. The term “adhesive capsulitis” may be a more accurate description for some patients.
As the name suggests, adhesive capsulitis affects the fibrous ligaments that surround the shoulder forming the joint capsule. This condition is referred to as primary adhesive capsulitis to differentiate it from “frozen shoulder” (secondary adhesive capsulitis).
Primary adhesive capsulitis is formed by inflammation, fibrosis, and contraction of the capsule with tiny adhesions holding the capsule to the bone. The normally loose parts of the joint capsule stick together. The result is pain and loss of motion from a mechanical (tissue) problem (adhesions causing tightness).
The condition referred to as a frozen shoulder usually doesn’t involve the capsule. Secondary adhesive capsulitis (or true frozen shoulder) might have some joint capsule changes but the shoulder stiffness is really coming from something outside the joint. Often, the short rotator muscles around the shoulder spasm. Sometimes, adhesions form inside the joint itself (rather than in the capsule).
Some of the conditions associated with secondary adhesive capsulitis (true frozen shoulder) include rotator cuff tears, biceps tendinitis, and arthritis. Any of these problems can seriously limit the shoulder’s ability to move, and causes the shoulder to “freeze.” Risk factors for adhesive capsulitis include: diabetes, thyroid problems, Dupuytren contracture, treatment for breast cancer, autoimmune diseases, and previous heart attack or stroke.
Current concepts in diagnosis and treatment of adhesive capsulitis were recently published. One of the most distinguishing characteristics of primary adhesive capsulitis is decreased shoulder external rotation when the arm is held next to the side. Active and passive shoulder motions will be equally limited when the capsule is involved. When these two types of motion differ, the problem may not be primary adhesive capsulitis.
Sometimes it is difficult to tell if motion is limited by capsular tightness versus the patient’s pain. That’s when it might be helpful to inject the joint with a numbing agent (e.g., lidocaine). Retesting the patient’s shoulder motion without the influence of pain can help differentiate between true primary adhesive capsulitis and some other cause of shoulder pain (and loss of motion). X-rays may be helpful in identifying these other causes of shoulder pain and blocked motion (e.g., osteoarthritis, dislocation, bone spurs, fractures, tumors).
Another useful diagnostic test to determine whether or not the joint capsule is involved is an arthrography. A dye is injected into the joint. Normally, the shoulder joint can hold about 15 milliliters of fluid. The person who has primary adhesive capsulitis will have a limited capacity because the portion of the capsule at the bottom (called the axillary fold) is contracted. No fluid can enter this normally pocket-like structure.
MRIs have limited ability to aid in the diagnosis of primary adhesive capsulitis. But an MRI can help rule out other causes and an MRI with contrast dye (arthrography) can show the presence of thickening in the joint capsule and ligaments. And when the MRI no longer shows the fat pad between the coracohumeral ligament and the coracoid process, the presence of primary adhesive capsulitis is confirmed.
Once the diagnosis has been made, then treatment can be prescribed. Physical therapy is the first line-of-treatment. It takes time to calm the pain signals and gain motion back, so a period of conservative care over several months is necessary. During this time, nonsteroidal antiinflammatory medications are often recommended for their short-term effects of providing pain relief. Steroid injections into the joint also provide a temporary decrease in pain and may aid in reducing inflammation in the early stages of the condition.
When conservative care fails to bring about the desired results, treatment may be expanded to include nerve blocks, hydrodilation (injecting a saline solution into the joint to expand/rupture the capsule), or manipulation under anesthesia (surgeon moves arm through full motion while patient is asleep).
When all else fails, surgery may be the last step. Arthroscopy is used to see inside the joint and release adhesions, scar tissue, and/or the capsule itself. Physical therapy after manipulation is required in order to maintain shoulder motion after manipulation or surgery.