Frozen shoulder is a condition in which movement of the shoulder becomes restricted. The condition can vary in severity from mild pain and/or less significant restriction of movement
to severe pain and/or severely restricted movement. Key characteristics are gradual onset of shoulder stiffness, severe pain, especially at night, and restriction in active and passive range of movement of the shoulder. Frozen shoulder can be described as either primary (idiopathic), if the aetiology is unknown, or secondary, when it can be attributed to another cause. It is commonly
a self-limiting condition, of approximately 1–3 years’ duration, although incomplete resolution can occur.