The shoulder joint is encased in a fibrous capsule which is made up of several ligaments. These ligaments help provide stability to the joint and are reasonably lax to allow movement. These ligaments tighten up at the extremes of movement to provide stability. A frozen shoulder is when the active movement of the arms are significantly restricted from the shoulder in all directions.
Frozen shoulder can be broadly classified into two categories:
- Primary/Idiopathic Adhesive Capsulitis
- Secondary Adhesive Capsulitis
Causes and Reasons:
Most of the causes for a frozen shoulder are still a mystery. Risk factors attributed to this condition are diabetes, thyroid disorders, etc. It can also occur in patients who have had a heart attack, stroke or undergone surgery for breast cancer. Secondary Adhesive Capsulitis can be caused by external factors like a fracture adjacent to the joint or tendon injuries. These can also be due to rotator cuff tears, impingement syndrome, biceps tendinitis and arthritis.
There are three stages categorized to this condition
- Freezing: The freezing stage is extremely painful and patients experiencing this condition are subdued to restrict movement due to the pain. The cause of this pain remains unidentified in most cases. The freezing stage lasts about 3 to 8 months and early signs can include the inability to move your arms like reaching back or raising your arm. Lying on your arm while sleeping can cause pain.
- Frozen: During this stage, the shoulder joints begin to lock, restricting further movement however the pain is diminished. Extreme movements however might still cause pain. The frozen stage lasts about 4 to 6 months.
- Thawing: The thawing stage is when the shoulder movement is significantly restricted though there is less pain. This stage lasts about 1 to 3 months.
- X-rays are of limited use in this condition
- A series of images, usually from an X-ray, is useful and will reveal if the capsule is contracted due to the fact that very little dye can be injected into the joint.
- An MRI helps distinguish between primary and secondary frozen shoulder