Adhesive Capsulitis of the Shoulder (Frozen Shoulder)

What happens in frozen shoulder

The shoulder is a ball-and-socket joint surrounded by a capsule of strong connective tissue. In adhesive capsulitis, this capsule becomes inflamed, then thickened and scarred, and the space inside the joint shrinks. The tight capsule restricts the ball from moving in the socket, so movement is lost in every direction. Despite the name, there are usually no true "adhesions" inside the joint.

Stages of frozen shoulder

Stages overlap and timings vary. Many people recover most movement, but some have mild lasting stiffness.

Symptoms

• A dull or aching pain over the outer shoulder and sometimes the upper arm
• Pain that is worse at night and when lying on that side
• Stiffness that makes it hard to reach overhead, behind your back (to fasten a bra or tuck in a shirt), or to the side
• Loss of outward rotation of the arm, often the first and most affected movement
• Stiffness that is the same whether you try to move the arm or someone else moves it for you. This is a key difference from a rotator cuff problem, where the arm can be moved passively

Causes and risk factors

The cause is not fully understood. It is thought to involve inflammation followed by fibrosis (scar-like tissue) in the capsule. Two types are recognized:

• Primary (idiopathic): develops with no obvious trigger.
• Secondary: follows shoulder injury, surgery, a fracture, or a period of immobility, such as after a stroke or a mastectomy.

Risk factors:

• Age 40 to 60 and female sex
• Diabetes: frozen shoulder affects up to around 20 percent of people with diabetes, tends to be more severe and last longer, and more often affects both shoulders
• Thyroid disease, both underactive and overactive (hypothyroidism and hyperthyroidism)
• Heart disease, stroke and Parkinson's disease
• Dupuytren's contracture (thickening in the palm)
• Prolonged immobilization of the arm
• Having had frozen shoulder in the other shoulder

Diagnosis

Frozen shoulder is diagnosed mainly by examination. A clinician will compare the range of movement of both shoulders, moving the arm actively (you move it) and passively (they move it). Loss of both, especially outward rotation, points to frozen shoulder.

• X-rays are used to rule out shoulder arthritis or a dislocation, which can cause similar stiffness. In frozen shoulder they are normal.
• Ultrasound or MRI may show capsule thickening and rule out a rotator cuff tear.
• Blood tests for blood sugar and thyroid function may be checked, as frozen shoulder can be the first sign of diabetes.

Frozen shoulder vs other shoulder problems

Treatment

Treatment aims to control pain and preserve or restore movement while the condition runs its course.

Pain relief

• Acetaminophen (paracetamol) or NSAIDs such as ibuprofen at the label dose, if suitable for you. Avoid NSAIDs with kidney disease, stomach ulcers or some heart conditions.
• Heat before stretching and ice after if painful.
• Sleeping with a pillow supporting the arm.

Steroid injection

A corticosteroid injection into the shoulder joint, ideally guided by ultrasound, reduces pain and helps restore movement, especially in the early, painful stage. Effects are strongest in the first weeks to months. People with diabetes should monitor blood sugar, which can rise for a few days afterward.

Physical therapy and home exercises

Gentle stretching within tolerable pain helps maintain and recover movement. Common exercises include:

• Pendulum swings: lean forward and let the arm hang and swing gently in small circles.
• Finger walks: walk your fingers up a wall in front of you and to the side.
• Towel stretch: hold a towel behind your back with both hands and gently pull the affected arm upward.
• Outward rotation with a stick: hold a stick with both hands, elbows at your sides, and push the affected hand outward.

Avoid forceful stretching during the painful freezing stage, as it can increase inflammation.

Other treatments

• Hydrodilatation: injecting a large volume of fluid with steroid into the joint to stretch the capsule.
• Manipulation under anesthesia: the arm is moved to stretch or tear the tight capsule while you are asleep.
• Arthroscopic capsular release: keyhole surgery to cut the tight capsule, for persistent severe stiffness after 6 to 12 months of other treatment.
• Suprascapular nerve block for pain control.

Outlook

Most people recover substantially over 1 to 3 years, with or without treatment. Treatment shortens the painful phase and speeds recovery of movement. Up to a third of people may have some mild long-term loss of movement, which often does not affect daily life. Recurrence in the same shoulder is rare, but the other shoulder is affected later in some people.

Frequently asked questions

What is adhesive capsulitis of the shoulder?

Adhesive capsulitis, or frozen shoulder, is a condition in which the tissue capsule around the shoulder joint becomes inflamed, thick and tight. It causes pain and progressive stiffness, so the arm cannot be lifted or rotated fully, even with help. It usually improves over 1 to 3 years.

What are the stages of frozen shoulder?

There are three overlapping stages. In the freezing stage, pain builds over weeks to months. In the frozen stage, pain eases but stiffness is worst. In the thawing stage, movement gradually returns. The whole process typically takes 1 to 3 years.

What causes frozen shoulder?

The exact cause is unknown. It involves inflammation and thickening of the joint capsule. It can follow an injury, surgery or immobilization of the arm, but often has no trigger. Diabetes, thyroid disease, age 40 to 60 and female sex increase the risk.

What is the fastest way to cure frozen shoulder?

There is no instant cure, but a steroid injection in the early, painful stage combined with gentle stretching and physical therapy often speeds recovery. Hydrodilatation, manipulation under anesthesia or keyhole release surgery are options for persistent severe stiffness.

Is frozen shoulder linked to diabetes?

Yes. People with diabetes are several times more likely to develop frozen shoulder, and it is often more severe, longer lasting and more likely to affect both shoulders. Some people are first diagnosed with diabetes after developing frozen shoulder.