Diabetics are at higher risk; up to 20 percent get it. For this reason, frozen shoulder may have an autoimmune component responsible for its development. Trauma sometimes precedes a frozen shoulder. People with other health conditions, including heart disease, lung disease and hyperthyroidism, also may have an increased risk of developing frozen shoulder.

Seventy percent of patients are middle-aged women and some specialists feel there may be hormonal factors involved.

The condition characterized by stiffness and pain in the shoulder joint. At the beginning there can be pain and some limitation of range of motion in the shoulder. With worsening, the shoulder's range of motion becomes markedly reduced.

Frozen shoulder usually affects one shoulder at a time, although some people can develop frozen shoulder in the opposite shoulder.

Frozen shoulder typically develops slowly, and in three stages. Each of these stages can last several weeks to months:

• Painful stage. During this stage, pain occurs with any movement of the shoulder and the range of motion starts to become limited.

• Frozen stage. Pain may begin to diminish during this stage. However, the shoulder becomes stiffer and the range of motion becomes dramatically reduced.

• Thawing stage. During the thawing stage, the range of motion in the shoulder begins to improve.

The pain is often worse at night and disrupts sleep.

The exact cause of frozen shoulder is unknown. As mentioned earlier, It can occur after an injury to the shoulder or after prolonged immobilization of the shoulder, such as after surgery or an arm fracture.

The shoulder is a ball-and-socket joint. The end of the humerus (upper arm bone) is shaped like a ball and fits into a shallow cup in the scapula (shoulder blade). Tough connective tissue forms a shoulder capsule that surrounds the joint.

As frozen shoulder develops, the shoulder capsule becomes inflamed. The inflammation causes adhesions (bands of stringy tissue) to develop within the shoulder joint. Synovial fluid, the normal lubricating fluid within the joint , decreases in volume.

As a result, pain and loss of range of motion occur. Mobility can decrease so much that performing simple activities of daily living such as dressing and undressing, brushing hair, and reaching up to shelves are difficult.

What are known risk factors for frozen shoulder? A few are:

• Age. People over the age of 40 are more likely to experience frozen shoulder.

• Diabetes and other systemic diseases. Frozen shoulder is more common in people with hyperthyroidism (overactive thyroid), hypothyroidism (underactive thyroid), cardiovascular disease and Parkinson's disease.

• Immobility. People who have experienced prolonged immobility of their shoulder as a result of trauma, overuse injuries or surgery.

The primary method for making the diagnosis of frozen shoulder is history and physical examination. The physician will assess both active range of motion (movement without assistance) and also passive range of motion (movement with assistance). The loss of both active and passive movement and the presence of generalized shoulder tightness and pain are strong indicators of frozen shoulder.

Imaging procedures such as X-ray or magnetic resonance imaging (MRI) scan of the shoulder should be done to exclude other structural shoulder problems.

Treatment of frozen shoulder treatment consists of controlling shoulder pain and preserving as well as improving the range of motion in the shoulder as much as possible to allow performance of activities of daily living.

Physical therapy is helpful in showing patients how to maintain as much mobility as possible. Stretching exercises, while painful, are important in establishing normal range of motion.

Patients should continue to use the involved shoulder in as many daily life activities as possible within the limits of pain.

A home program of range of motion exercises won't alleviate the symptoms of frozen shoulder. However, it can help restore enough shoulder motion to help a person resume their everyday activities.

Other therapies that may be useful include:

• Non-steroidal anti-inflammatory drugs (NSAIDs). These medications can help to relieve pain and inflammation.

• Heat or cold. Application of heat or cold to the shoulder also can relieve pain. Topical agents may also be useful.

• Glucocorticoids ("steroids"). Injecting these anti-inflammatory compounds into the shoulder can decrease pain and shorten symptoms duration during the initial painful phase. Glucocorticoids need to be injected into both the glenohumeral joint (joint between the humerus and scapula) as well as the subacromial bursa, the area that sits at the top of the humerus where it interacts with the clavicle (collarbone). The reason is that the adhesions in a frozen shoulder prevent the spread of the steroid medicine around the joint so the steroid needs to be injected into the two major areas where the adhesions seem to cause the biggest problem. However too many repeated steroid injections aren't recommended.

• Surgery. In a small number of cases, especially if symptoms don't improve despite other measures, surgery may be an option to remove adhesions and other scar tissue that has accumulated inside the shoulder joint. Doctors usually perform this surgery with an arthroscope (a small telescope) that is inserted through a small incision.

• Shoulder manipulation. In a few people, if severe stiffness persists, manipulation of the shoulder while the patient is under general anesthesia can mobilize the shoulder. The danger is that occasionally the arm can break during manipulation.

There are still some physicians who tell a patient to let the shoulder alone and bear with it since the majority of patients with adhesive capsulitis recover spontaneously over a two year period of time. I personally believe that is not the correct approach since the pain during the acute phase can be so intense and the reduced mobility during the "frozen" stage can be so debilitating. Aggressive treatment is, in my opinion, the better approach.