Though it’s unclear why, adhesive capsulitis (commonly known as frozen shoulder) is more common in people with endocrine problems, including thyroid disease. Frozen shoulder often starts with difficulty moving your shoulder or dull, aching pain in your shoulder area. It gets worse over time and can eventually limit your shoulder mobility.

This article explains the correlation between frozen shoulder and thyroid disease. It also covers frozen shoulder symptoms, diagnosis, and treatment.

Causes and Risk Factors for Frozen Shoulder

The bones, ligaments, and tendons of the shoulder joint are wrapped in connective tissue. Frozen shoulder occurs when this capsule thickens and inflames, causing it to contract and form scar tissue.

Potential causes of frozen shoulder include:

  • Shoulder injury or trauma
  • Shoulder surgery
  • Surgery that immobilizes your shoulder, such as breast surgery or open-heart surgery
  • Hormonal changes, such as perimenopause and menopause
  • Cervical disk disease of the neck

In addition, frozen shoulder is also a risk factor for those who have thyroid conditions. Though the link between thyroid disease and frozen shoulder remains uncertain, research has revealed some possible connections with hyperthyroidism and hypothyroidism.

Hyperthyroidism and Frozen Shoulder

A 2014 study analyzed records of 1 million people in a health insurance database to determine the prevalence of frozen shoulder in people with hyperthyroidism. The study followed 4,472 people with hyperthyroidism over seven years. Within that period, 162 of them developed frozen shoulder.

What Are Hyperthyroidism and Hypothyroidism?

Hyperthyroidism is a condition that results from your thyroid producing too much thyroid hormone.

The research concluded that compared to a control cohort, those with hyperthyroidism were 1.22 times more likely to develop frozen shoulder than the general population in the 7-year follow-up period.

The researchers speculated that this increased risk might be related to an inflammatory process stimulated by the production of proteins known as cytokines (proteins that act as messengers between cells). Elevated levels of cytokines happen in both hyperthyroidism and frozen shoulder. Conceivably, one could trigger the other, or they could occur in tandem.

Hypothyroidism and Frozen Shoulder

Another study evaluated 93 participants with frozen shoulder and 151 without the condition. The researchers found that hypothyroidism was significantly higher in those with frozen shoulder.

In addition, those with elevated thyroid-stimulating hormone (TSH)—a hormone produced by the pituitary gland in the brain that sends messages to the thyroid—were more likely to have more severe frozen shoulder, or to have bilateral frozen shoulder (both shoulders affected).

Finally, myopathy (muscle pain) is common in hypothyroidism and hyperthyroidism. Whether this is related to frozen shoulder specifically, however, is not clear.

Symptoms of Frozen Shoulder

Frozen shoulder symptoms usually develop slowly over time and worsen gradually. Often, the condition begins with mild pain over several months. It typically goes through three stages, with different symptoms evident at each stage.

Recap

Frozen shoulder may be caused by injury, surgery, hormonal changes, and thyroid disease. Researchers have found a correlation between thyroid conditions and frozen shoulder, but the reason for this relationship is not apparent.

Freezing Stage

This stage is usually the most painful. In the freezing stage, pain is most severe in your outer shoulder area. This stage typically lasts between six weeks and nine months.

In some cases, you may also have pain radiating down into your upper arm. Moving your shoulder can be painful, so daily activities that require you to lift your arm—such as brushing your hair or reaching something on a high shelf—can become difficult.

You may have pain while sleeping as well. Your range of motion in the shoulder is also typically reduced.

Frozen Stage

During this stage, the range of motion of your shoulder is even more limited, and your shoulder becomes stiffer. As a result, it can become increasingly difficult to lift your arms or move your arms backward. 

Over time, the shoulder can become so stiff that it is almost impossible to move. However, you may notice that your pain lessens as your shoulder becomes less mobile. This stage lasts for four to six months.

Thawing Stage

During the thawing stage, you typically have less pain. The range of motion improves over time. Complete recovery can take up to two years.

Diagnosis

Diagnosing a frozen shoulder can be tricky. That’s because the main symptoms—pain and stiffness—are characteristic of numerous other conditions, including rotator cuff injuries. As a result, healthcare providers often misdiagnose a frozen shoulder as a tear in the rotator cuff.

Frozen shoulder symptoms occur in stages: freezing, frozen, and thawing. Complete recovery can take up to two years.

People with frozen shoulder sometimes compensate for reduced shoulder joint movement by moving their shoulder blades and spine in specific ways. This altered movement adds to the challenge of getting an accurate diagnosis.

To diagnose a frozen shoulder, a healthcare provider will do a physical exam and assess your symptoms. Since both active (moving your own shoulder) and passive range of motion (when someone else moves your shoulder) are affected by the frozen shoulder, they will also want to assess how your shoulder moves.

Diagnostic tests may include:

  • Active and passive range of motion tests
  • X-rays
  • Magnetic resonance imaging (MRI)

Treatment

Frozen shoulder usually resolves on its own over time. However, this can mean several years of pain and restricted mobility until the shoulder returns to normal. In some cases, the full range of motion in the shoulder never returns.

When frozen shoulder is identified and diagnosed early, treatment may help.

Cortisone Injections

A cortisone injection directly into the frozen joint can help restore range of motion and may help speed the healing time dramatically. Cortisone injections commonly treat joint problems. Cortisone is an anti-inflammatory steroid that reduces pain by reducing inflammation.

NSAIDs

Nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce pain and inflammation in some cases. NSAIDs, such as ibuprofen (Advil, Motrin), aspirin, and naproxen (Aleve) are convenient because they are available over the counter (OTC). You can also get them in prescription strength.

This approach, especially when combined with physical therapy, may help restore the range of motion and relieve pain. However, it can take as long as a year to get total relief.

Physical Therapy

As opposed to more aggressive physical therapy, gentle stretching can complement medication treatment. For example, you might learn specific exercises designed to stretch and increase your shoulder’s range of motion under the guidance of a physical therapist (PT). Alternately, a healthcare provider may provide instructions to do them on your own, at home.

Transcutaneous electrical stimulation (TENS) is a treatment that PTs sometimes use to relieve pain. It uses a battery-operated device that works by delivering electrical impulses. These can help modify your body’s pain signals and significantly increase range of motion. So, a physical therapist may use one during treatment. Or they may direct you on how to use it at home.

Finally, diathermy is a treatment method that uses low-power laser therapy and deep heating to improve circulation and decrease pain. When this therapy is combined with stretching, it may also provide relief.

Surgery

Surgery for frozen shoulder is the last resort, but a healthcare provider may recommend it if other options are not effective. Surgery—often performed arthroscopically—focuses on removing scar tissue and adhesions in the shoulder.

Unlike open surgery, which uses a scalpel to create a large incision to open the skin and tissue, arthroscopic surgery is less invasive. In arthroscopy, a special scope (camera) and tools access a joint through tiny incisions. Instead of looking directly at the surgical area, a camera transmits the image on a monitor, which a surgeon views as they work.

Following surgery, physical therapy is typically necessary to restore and maintain the range of motion in the shoulder.

Managing Your Thyroid Condition

Since there is a connection between thyroid disease and frozen shoulder, it is vital that you manage your thyroid condition. Treatment for thyroid conditions vary but may include:

  • Medication
  • Radioactive iodine (RAI)
  • Thyroidectomy (surgery to remove some or all of the thyroid)
  • Hormone replacement therapy

Summary

While the association is not fully understood, there is a connection between thyroid conditions and frozen shoulder. Frozen shoulder is characterized by pain and decreased shoulder joint mobility. It gradually progresses, and recovery can take up to two years.

Frozen shoulder treatment may include cortisone injections, painkillers and anti-inflammatory medications, physical therapy, and surgery. In addition, managing your thyroid condition is also essential. Thyroid treatments may include medicine, hormone replacement therapy, surgery, or radioactive iodine, depending on the situation.

Diagnosing frozen shoulder involves range of motion tests. It may also include imaging tests. Treatment consists of pain and anti-inflammatory medication, physical therapy, surgery, and managing your thyroid condition.