Frozen shoulder: hydrodilatation explained

Frozen shoulder, or adhesive capsulitis, is a condition where the shoulder capsule becomes inflamed and stiff. It typically starts with pain, often at night, and then progresses to stiffness that limits reaching overhead, behind the back, or out to the side.

It is more common in people aged 40–60, women, and those with diabetes or thyroid disease. It can also develop after the shoulder has been immobilised for another injury. The natural history is self-limited — it usually improves over 1–3 years — but that is a long time to wait when sleep and daily activities are affected.

Hydrodilatation, also called capsular distension, is an injection of sterile fluid — often with a small amount of corticosteroid and local anaesthetic — directly into the shoulder joint. The aim is to stretch the tight capsule from the inside and reduce inflammation at the same time.

The procedure is done in the clinic under ultrasound guidance. It takes only a few minutes. Most patients feel pressure during the injection, but it is not usually painful. The shoulder is then gently moved through its range to take advantage of the fluid stretch.

Pain relief often begins within 48–72 hours as the steroid reduces inflammation. Range of motion typically improves over the following 2–6 weeks. Hydrodilatation does not instantly cure frozen shoulder, but it can shorten the painful phase and make physiotherapy much more effective.

We combine the injection with a structured home stretching programme. Patients perform pendulum exercises, wall walks, and gentle external rotation stretches several times a day. The combination of mechanical loosening and consistent movement gives the best results.

Hydrodilatation is most helpful in the painful or freezing phase, before the shoulder becomes extremely stiff. It is less effective in the very late, 'frozen' phase, where stiffness rather than pain is the main problem. In those cases, manipulation under anaesthesia or arthroscopic capsular release may be discussed.

If you have diabetes, the condition can be more stubborn and the recovery slower. We still use hydrodilatation, but expectations are adjusted and the stretching programme is more prolonged. Early treatment is the key to avoiding months of disability.