Frozen shoulder, or adhesive capsulitis, occurs when inflammation and scar tissue invade the shoulder joint. It's believed to be a form of autoimmune disease in which the body overreacts to a minimal injury and then cells in the joint release inflammatory chemicals that cause pain. Ultimately the cells in the joint capsule create scar tissue, which produces a stiff shoulder.
Symptoms of a frozen shoulder include
- stiffness that worsens at first, but gradually begins to improve over time
- dull, aching pain that increases as the disease progresses, and may worsen when you move your arm.
Frozen shoulder affects between 2% and 5% of people overall. Although the exact cause of frozen shoulder isn't clear, it is more common in people with conditions like diabetes, Parkinson's disease, and thyroid disease. Frozen shoulder can also develop after the shoulder has been immobilized for a long period of time—for example, following an injury, a stroke, or surgery. It is more common in women than men.
Frozen shoulder typically progresses through three stages, although the duration of each stage varies from person to person.
Stage 1: Freezing. The shoulder becomes inflamed and the shoulder capsule progressively shrinks, leading to increasing pain and stiffness. This stage can last from two to nine months.
Stage 2: Frozen. The shoulder remains stiff, limiting range of motion. However, the pain begins to recede. This stage lasts from four to six months.
Stage 3: Thaw. The stiffness improves, and you gradually gain more motion in the shoulder. Most of the time the condition gets better on its own, yet it can take between six months and two years to fully regain movement and function in the affected shoulder.
The typical treatment involves physical therapy, along with medication to manage pain and inflammation. However, there is controversy about the role of physical therapy. Too much stretching can worsen the condition, while too little will allow it to continue. This makes it crucial to find the right balance. Often, physical therapists will start with stretches that are very gentle and brief (one to five seconds), and then slowly progress to muscle strengthening and mobility exercises as the shoulder condition improves. In addition to therapy sessions, people should stretch on their own at home to speed healing.
For more tips on troubleshooting common shoulder problems, read Healing Shoulder Pain, a Special Health Report from Harvard Medical School.
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