Frozen shoulder is divided into two categories: primary and secondary. Primary frozen shoulder, also known as idiopathic frozen shoulder, has not been found to have a clear cause. Secondary frozen shoulder refers to shoulder pain and joint stiffness secondary to trauma and surgery on the affected upper extremity. Differentiating primary frozen shoulder from secondary frozen shoulder is crucial for choosing a reasonable treatment. Deng Lei, Department of Traumatology, Xiyuan Hospital, Chinese Academy of Traditional Chinese Medicine
Diagnosis of primary frozen shoulder is based on 1. no clear history of trauma or surgical treatment to the shoulder; 2. limited movement of the shoulder joint in all directions on examination; 3. normal joint space on X-ray plain examination and no abnormalities around the joint (such as bone spurs).
The diagnosis of secondary frozen shoulder is based on 1. a clear history of trauma, low energy trauma, or surgery in and around the joint area; 2. limited movement of the shoulder joint in one direction, multiple directions, or all directions on examination; 3. normal joint space on radiograph.