Adhesive capsulitis of the shoulder

Adhesive capsulitis, also known as frozen shoulder, is a condition associated with shoulder pain and stiffness. Onset is gradual over weeks to months. A common shoulder ailment, adhesive capsulitis is marked by pain at rest but especially upon movement, as well as a decrease in range of motion (particularly in external rotation). The shoulder itself, however, often does not hurt significantly when touched.

The exact cause in most cases is unknown. The condition can also occur after injury or surgery to the shoulder. The underlying mechanism involves inflammation and scarring within the shoulder joint itself.

Diagnosis is generally based on a person's symptoms and a physical exam. A key feature that can distinguish adhesive capsulitis from similar conditions is the inability of others to move the shoulder, in addition to the loss of voluntary movement (a loss of both active and passive ranges of motion). This is in contrast to most muscle, tendon, and nerve disorders, where only the active range of motion is limited. The diagnosis may be supported by an MRI or ultrasound.

The condition can sometimes resolve itself over time without intervention, but this may take several years, and results are better when it is treated. There are a number of non-procedural treatments, including nonsteroidal anti-inflammatory drugs, physical therapy, and oral or injected steroids. Surgery is an option for those who do not improve after other treatments. Additional methods of treatment include nerve block, high pressure saline injection, plasma injection, and extracorporeal shockwave therapy.

Frozen shoulder is most common in people 40–60 years of age. It is also significantly more common in women. Major risk factors include diabetes and thyroid disease. Approximately 2-5% of people have adhesive capsulitis at any given time.