Inflammation causes parts of the joint capsule in the shoulder joint to become fibrotic, reducing the volume of the shoulder joint, limiting the shoulder's ability to move and causing the shoulder to freeze.
Frozen shoulder can happen with no obvious cause, which is known as primary frozen shoulder.
Primary frozen shoulder is associated with several risk factors, including:
It tends to affect adults over 40 years and is more common in women.
Frozen shoulder also tend to occur more frequently in patients with endocrine disorders such as diabetes, cardiac disease or thyroid problems, Parkinson's disease or if you have undergone surgery.
In secondary frozen shoulder, this can occur commonly after prolonged immobilisation of the shoulder after injury, or due to pain that limits shoulder motion (such as after injury to the rotator cuff muscles of the shoulder) eventually leading to this disease.