The shoulder joint (glenohumeral joint) is a ball and socket joint comprised of the ball of the humerus (arm bone) and socket (glenoid) of the scapular (shoulder blade). The shoulder joint is very mobile and is stabilised by a thickened ligament called the capsule. The role of this capsule is to keep the ball in the socket during movement (ie, preventing dislocation of the head of the humerus).
Adhesive capsulitis, or “frozen shoulder” occurs when the capsule of the shoulder becomes inflamed. This condition can be very painful and presents with a marked reduced range of movement. People suffering from this condition report difficulty with functional activities such as getting dressed, reaching behind their back and washing their hair, and often have difficulty sleeping.
Frozen shoulders can arise as a result of a traumatic fall or injury but equally can occur after shoulder surgery or periods of immobilisation (even as little as 48 hours). It is more common in males than females, and has a higher incidence in people with diabetes. Sometimes there is just no explanation for the onset.
There is a typical pattern to a frozen shoulder. The Inflammatory phase occurs first with people usually reporting the initial pain and stiffness; this can last 6 months or longer. As the pain begins to settle, the second phase is characterised by significantly reduced shoulder movement in all directions and therefore problems with function – hence the name “frozen shoulder”. Finally, the final phase is the ‘thawing’ phase, which involves improving movement and resolving pain.
A frozen shoulder can benefit from physiotherapy to help maintain a functional range of movement whilst the shoulder progresses through the phases. A frozen shoulder will usually resolve and in 95% of cases a full recovery is made, although it can take as long as 18 months to be back to normal.