Cortisone injections are given directly into, or near to the shoulder joint. It reduces the inflammation within the frozen shoulder joint. Cortisone is a type of corticosteroid released by the adrenal gland in response to stress.

Cortisone is a potent anti-inflammatory medicine that can reduce inflammation, but is not pain reliever. Cortisone injections typically result in pain relief within a few days, which is because the inflammation diminishes. The effects may last for several weeks.

The most common side effect is a “cortisone flare”. This is a condition where the injected cortisone crystallizes and causes a brief period of severe pain, that usually only lasts for a day or two. This is treated by application of ice to the injected area. Other side effects include whitening of the skin at the injection site, infection, a transient elevation in their blood sugar in patients with diabetes.