Frozen shoulder, also called adhesive capsulitis, involves stiffness and pain in the shoulder joint. Signs and symptoms typically begin slowly, then get worse. Over time, symptoms get better, usually within 1 to 3 years.
Having to keep a shoulder still for a long period increases the risk of developing frozen shoulder. This might happen after having surgery or breaking an arm.
Treatment for frozen shoulder involves range-of-motion exercises. Sometimes treatment involves corticosteroids and numbing medications injected into the joint. Rarely, arthroscopic surgery is needed to loosen the joint capsule so that it can move more freely.
It's unusual for frozen shoulder to recur in the same shoulder. But some people can develop it in the other shoulder, usually within five years.
Frozen shoulder typically develops slowly in three stages.
- Freezing stage. Any movement of the shoulder causes pain, and the shoulder's ability to move becomes limited. This stage lasts from 2 to 9 months.
- Frozen stage. Pain might lessen during this stage. However, the shoulder becomes stiffer. Using it becomes more difficult. This stage lasts from 4 to 12 months.
- Thawing stage. The shoulder's ability to move begins to improve. This stage lasts from 5 to 24 months.
For some people, the pain worsens at night, sometimes disrupting sleep.
The shoulder joint is enclosed in a capsule of connective tissue. Frozen shoulder occurs when this capsule thickens and tightens around the shoulder joint, restricting its movement.
It's unclear why this happens to some people. But it's more likely to happen after keeping a shoulder still for a long period, such as after surgery or an arm fracture.
Certain factors may increase the risk of developing frozen shoulder.
Age and sex
People 40 and older, particularly women, are more likely to have frozen shoulder.
Immobility or reduced mobility
People who've had to keep a shoulder somewhat still are at higher risk of developing frozen shoulder. Restricted movement can be the result of many factors, including:
- Rotator cuff injury
- Broken arm
- Recovery from surgery
People who have certain diseases appear more likely to develop frozen shoulder. Diseases that might increase risk include:
- Overactive thyroid (hyperthyroidism)
- Underactive thyroid (hypothyroidism)
- Cardiovascular disease
- Parkinson's disease
One of the most common causes of frozen shoulder is not moving a shoulder while recovering from a shoulder injury, broken arm or stroke. If you've had an injury that makes it difficult to move your shoulder, talk to your health care provider about exercises that can help you maintain your ability to move your shoulder joint.