Frozen Shoulder (Adhesive Capsulitis)

What is frozen shoulder?

The shoulder joint is wrapped in a capsule of connective tissue. In frozen shoulder this capsule first becomes inflamed, then thickens and stiffens, and scar-like bands called adhesions form inside it. The space inside the joint shrinks, so the arm can no longer move normally ^[1]⁠^[2].

The typical feature is that the shoulder is stiff both when the person tries to lift the arm and when someone else, such as a doctor, tries to move it for them. This helps tell frozen shoulder apart from tendon problems, where the shoulder hurts but can usually still be moved by another person ^[2].

Frozen shoulder usually passes through three overlapping stages ^[2]:

• Freezing stage: pain slowly increases and movement is lost; lasts roughly 6 weeks to 9 months.
• Frozen stage: pain may ease but stiffness remains and daily tasks become harder; lasts about 4 to 6 months.
• Thawing stage: movement gradually returns over about 6 months to 2 years.

What are the symptoms?

Symptoms start gradually and build up over weeks. The most common are ^[1]⁠^[2]:

• Shoulder pain, often worse at night and disturbing sleep
• Stiffness that makes it hard to lift the arm, move it out to the side or reach behind the back
• Difficulty with everyday tasks such as dressing, combing hair or reaching a back pocket
• Restricted movement both when moving the arm yourself and when it is moved for you

Causes and risk factors

The exact cause of frozen shoulder is not fully understood. Inflammation in the tissues around the joint is thought to make the capsule tighten and shrink. It often starts without any obvious injury ^[1].

The following increase the risk ^[1]⁠^[2]:

• Age between 40 and 60; it is more common in women
• Diabetes, which clearly raises the risk
• Thyroid disease, Parkinson's disease and heart disease
• A period when the shoulder was kept still, for example after an injury, a fracture or surgery

How is frozen shoulder diagnosed?

The diagnosis is usually made from the history and a physical examination. The doctor compares how far the person can move the arm on their own with how far it can be moved for them; in frozen shoulder both are limited ^[2].

An X-ray does not show the capsule, but it is used to rule out arthritis and other bone problems. MRI or ultrasound may be used if another soft tissue problem, such as a rotator cuff tear, is suspected ^[2].

Treatment

The aim of treatment is to control pain and keep or regain movement while the condition runs its natural course. Most people improve without surgery ^[1]⁠^[2].

Non-surgical options include ^[1]⁠^[2]:

• Painkillers and anti-inflammatory medicines, while avoiding very painful movements in the early stage ^[1].
• A steroid injection into the shoulder joint: research shows that an injection given within the first year of the condition gives better short-term pain relief and function than other options, and the benefit is greater when combined with home exercises ^[3].
• Physiotherapy and home exercises: gentle stretching and range-of-motion exercises are the basis of treatment. A Cochrane review found that physiotherapy and exercise alone may not relieve pain as quickly as an injection in the first weeks, but differences at 6 to 12 months are small ^[4].
• Hydrodilatation: fluid is injected into the joint to stretch the capsule. It may give short-term improvement, but its long-term role is still unclear ^[2]⁠^[5].

When is surgery needed?

If marked stiffness remains despite several months of non-surgical treatment, options include manipulation of the shoulder under general anaesthesia or keyhole (arthroscopic) release of the tight capsule. Physiotherapy must continue after either procedure ^[2].

Recovery: how long does frozen shoulder last?

Frozen shoulder heals slowly. Recovery can take months or even years, but pain and stiffness usually go away in the end ^[1]. In some people the whole process can last up to about three years ^[2].

Doing the exercises regularly and patiently matters; physiotherapy programmes usually last at least 6 weeks ^[1]. After surgery, recovery generally takes 6 weeks to 3 months, with physiotherapy continuing during this time ^[2].

Throughout treatment, it is advised to avoid forceful movements that clearly worsen the pain while still moving the shoulder with gentle exercises. Once a physiotherapist has taught them, the exercises can be done regularly at home ^[1].

When to see a doctor urgently

Frozen shoulder develops slowly. The following signs may point to a different and more serious problem, and medical help should be sought straight away ^[6]:

• Sudden or very severe shoulder pain
• Being unable to move the arm at all
• A change in the shape of the shoulder or marked swelling
• Pins and needles or numbness in the arm, or the arm feeling hot or cold
• Pain that started after a fall or injury
• Shoulder pain together with fever or feeling generally unwell