Frozen shoulder (adhesive capsulitis)

The shoulder joint sits inside a capsule, a bag of connective tissue that normally stretches easily and lets the arm travel in every direction. In adhesive capsulitis that capsule becomes inflamed, then scars and shrinks, like a shirt that has come out of the wash two sizes smaller. The joint itself is intact, the cartilage is not destroyed, the muscles work — and yet the arm meets an invisible wall and goes no further. The everyday name describes the feeling exactly: the shoulder has frozen. It is a slow illness, often lasting more than a year, and the hard part is not the treatment but the patience, and not mistaking it for the other causes of shoulder pain.

The three stages a shoulder goes through

The pattern is recognisable, and it helps to know it: understanding which stage you are in explains why today's symptoms are not the ones you had a few months ago.

Freezing. For the first months pain is in charge. It creeps in without an obvious cause, worsens towards night and makes it impossible to lie on that side. Movement gradually shrinks, but most people put that down to the pain: it feels as though the arm will not lift because lifting hurts. This stage usually runs from two to nine months.

Frozen. The pain settles and stiffness takes over, reaching its worst. Only now does the scale of the loss become obvious: you cannot fasten a bra, take a wallet out of a back pocket, reach the seatbelt, wash your hair or pull off a jumper. This stage lasts from four months to a year.

Thawing. The capsule slowly begins to give and range of movement comes back. This is the longest stage and the least noticeable: progress is measured in months rather than weeks. Full recovery takes one to three years from the start, and some people are left permanently with a small restriction, usually when reaching behind the back, which barely interferes with daily life.

A handful of sensations run through all three stages:

• a dull, deep ache in the shoulder that often travels down the outer arm as far as the elbow;
• a sharp catch on a quick, clumsy movement — reaching for the seatbelt, grabbing something as it falls;
• rotation outwards is lost first and worst: tuck the elbow into your side and swing the forearm away from you, as though opening a door;
• the shoulder refuses to move even when someone else moves it, and that is the key difference from most other causes of shoulder pain;
• an involuntary workaround: the arm is raised by hitching the whole shoulder up and turning the body.

What is usually absent: swelling, redness, heat in the joint, numbness or weakness of the hand. If those appear, the picture has changed and needs looking at.

Why the capsule tightens

The honest answer is that often nobody knows: a large share of cases turns up in healthy people with no trigger at all. There are, however, circumstances that clearly raise the odds.

• Diabetes is the strongest known factor. Frozen shoulder is several times commoner, runs a heavier and longer course, responds less well to treatment and more often goes on to affect both sides. It is put down to the way excess sugar alters the proteins of connective tissue.
• Thyroid disease, particularly an underactive thyroid.
• Enforced stillness of the arm: after a fracture, after shoulder or chest surgery, after a stroke, or from wearing a sling too long. A shoulder stiffens faster than the injury it was immobilised for can heal.
• Age between forty and sixty; it is vanishingly rare in children and young adults.
• It is commoner in women.
• Dupuytren's contracture in the palm, Parkinson's disease and previous heart surgery.

One detail worth knowing in advance: roughly one person in five eventually develops the same problem in the other shoulder, usually years later. A second episode on the same side, by contrast, is uncommon.

What it gets mistaken for

Shoulder pain has a good dozen causes, and confusing them is costly, because the treatments differ.

• Rotator cuff injury is the commonest mix-up. It also hurts and also makes lifting hard, but if a clinician lifts the relaxed arm, it goes up without resistance. In capsulitis it goes up neither by your own strength nor by anyone else's.
• Shoulder osteoarthritis causes similar stiffness, but usually in older people and with grating; an X-ray tells them apart.
• Calcium deposits in a tendon cause sudden, ferocious pain lasting a few days and show up clearly on an X-ray.
• The neck. A cervical disc or arthritis refers pain into the shoulder and shoulder blade, but shoulder movement is preserved, and there is pins and needles and weakness in the hand instead.

Then there are the rare but serious causes, which are the real reason to have a painful shoulder looked at: infection in the joint (a hot, swollen shoulder with fever), a tumour at the apex of the lung pressing on the nerve plexus and announcing itself as shoulder pain, bone secondaries, and also the heart and the gallbladder, whose pain radiates to the shoulder while restricting no movement at all.

How the diagnosis is reached

The basis is examination rather than technology. The clinician compares how far the arm moves under its own power with how far it can be taken by someone else's hand; loss of both, especially of outward rotation, with a clear X-ray, is the diagnosis.

The X-ray is not taken to see the capsulitis, which does not show, but to rule out arthritis, fracture, calcification and tumour. Ultrasound and MRI are not needed by everyone: they are kept for atypical presentations or for planning surgery. It is also worth checking blood sugar and thyroid function, since a frozen shoulder is sometimes what leads to a diagnosis of diabetes.

What genuinely helps

The main thing first: there is no way to thaw a shoulder quickly, and anyone promising results in a week is misleading you. Treatment has two aims — take the pain away now, and stop more movement being lost than has to be.

• Pain relief. Simple analgesics such as paracetamol, and non-steroidal anti-inflammatory drugs, the latter in a short course and cautiously if there is stomach, kidney or heart trouble. Choose with a doctor or pharmacist, particularly if you already take something regularly.
• A steroid injection into the joint. It earns its keep in the first, painful stage: it lifts the pain for weeks or months and finally makes the exercises possible. Later, when only stiffness is left, it does much less. An important warning for anyone with diabetes: blood sugar rises for a few days after the injection, sometimes markedly — this is expected, but it calls for closer monitoring.
• Distending the capsule with fluid. Under ultrasound or X-ray guidance, a volume of fluid containing local anaesthetic and an anti-inflammatory is put into the joint, gently stretching the shrunken capsule from inside.
• Physiotherapy. The point is not to build muscle but to win back a little range every day. Consistency beats effort: short sessions several times a day do more than one exhausting workout.
• Heat before exercises relaxes the tissue; cold afterwards settles an irritated shoulder.
• Surgery comes up when a year of treatment has shifted nothing and the stiffness is disabling: the capsule is either stretched under anaesthetic or divided through a keyhole. Exercises restart at once, otherwise everything tightens again.

Exercises to do at home

They are easy enough to learn, but it is better to be shown the first time. The rule: stretch until you feel tension and mild discomfort that fades within minutes of stopping. Sharp pain that lasts for hours and keeps you awake means you have pushed too hard.

• Pendulum. Lean forwards with your good hand on a table and let the affected arm hang free. Swing it forwards and back, side to side and in circles, using your body's sway rather than the arm's muscles.
• Wall walk. Walk the fingers of the affected arm up a wall, mark how far you got, and try a centimetre higher next time.
• Towel behind the back. Drape a towel over your shoulder and pull the lower end with the good hand, helping the affected one climb up your back.
• Outward rotation. Tuck the elbow into your side, bend the arm to a right angle and take the forearm outwards, helped by the other hand or by a walking stick. This is the most important movement, because it is the first one lost.
• Cross-body reach. Hold the affected arm at the elbow with the good hand and draw it gently across towards the opposite shoulder.

What not to do: work through severe pain, jerk the arm, invent your own loading on gym machines and, at the other extreme, protect the shoulder completely and keep it in a sling. Complete rest here is the shortest route to losing even more movement.

When it cannot wait

See a doctor the same day if:

• the shoulder is swollen and hot, the skin over it red, and you have a fever or chills;
• the pain came on suddenly after a fall or a blow, the shoulder has changed shape, or the arm will not move at all;
• numbness, pins and needles or weakness appear in the hand, or the arm is cold or pale;
• shoulder pain comes with a cough, breathlessness, unexplained weight loss, a drooping eyelid or sweating on only one side of the face;
• you have been treated for cancer and a constant shoulder pain has appeared that wakes you at night.

Call an ambulance at once (in European countries, the single number 112) if shoulder or arm pain arrives together with tightness, burning or heaviness in the chest, breathlessness, cold sweat or faintness. That is how a heart attack presents, especially when it radiates to the left shoulder or to both arms, and it must not be waited out.

Online consultation

Frozen shoulder is exactly the sort of problem a remote appointment handles well. The doctor will ask how the pain started and what you have stopped being able to do, ask you to show a few movements to the camera — lifting the arm forwards and out to the side, turning the forearm outwards, reaching behind your back — and from that alone can separate a tightened capsule from tendon damage or pain travelling down from the neck. They will explain which stage you are in and what to expect over the coming months, go through what you can take for pain alongside your other medicines, teach the exercises and how to spread them through the day, and discuss whether an injection is worth it and when it does most good. If you live with diabetes, blood sugar and preparing for the procedure deserve a conversation of their own. What cannot be settled online is anything needing hands and images: a fresh injury, a hot swollen shoulder, weakness and numbness in the arm all call for a face-to-face examination, and the doctor will say so plainly.

This material is for information only and does not replace medical advice.