Adhesive Capsulitis (or Frozen Shoulder) is a painful condition which results in a severe loss of motion in the shoulder. It may follow an injury to the shoulder, but may also arise gradually with no warning or injury.
The cause of this condition is largely a mystery. One theory is that the condition may be due to an autoimmune reaction. During an autoimmune reaction, the body’s defence system that normally protects it from infection mistakenly begins to attack parts of the body itself. The body thinks that the tissue it is attacking is foreign material. This causes an intense inflammatory reaction to the tissue that is under attack. The shoulder actually “freezes up” due to the severe inflammation of the joint capsule. The loose tissue of the joint capsule that usually allows a great deal of motion at the shoulder sticks together, limiting the motion. Why this should suddenly occur is a mystery.
Frozen Shoulder may begin following other injuries, where the shoulder is not moved around normally because of the other injury. A common example is after a wrist fracture, where the arm may be kept in a sling for several weeks. For some reason, this seems to start the process in some people.
The condition can begin while other shoulder problems are present. Sometimes, problems such as bursitis, impingement syndrome, or a partial rotator cuff tear can lead to a frozen shoulder as well. The pain from the first condition may cause you to decrease the use of the shoulder, and the underlying condition itself may lead to chronic inflammation. Usually, the adhesive capsulitis must be treated first to regain motion in the shoulder before the underlying problem can be addressed.
The symptoms of Frozen Shoulder are primarily pain and a very reduced range of motion in the joint. The range of motion is the same whether you are trying to move the shoulder under your own power or if someone else is trying to raise the arm for you. There comes a point in each direction of movement where the motion simply stops as if there is something blocking the movement. The shoulder usually hurts when movement reaches the limit of the range of motion, and it can be quite painful at night.
The diagnosis of Frozen Shoulder is usually made on the history and physical examination. One key finding that can help differentiate this from a rotator cuff tear is how the shoulder moves. In adhesive capsulitis the shoulder motion is the same, whether the patient or the doctor tries to move the arm. In a rotator cuff tear, the patient cannot move the arm, but when someone else lifts the arm it can be moved in a nearly normal range of motion.
As the motion increases in the shoulder, your doctor may suggest tests for an underlying condition, such as impingement, or a rotator cuff tear, that may have initiated the condition. Probably the most common test used is the ultrasound scan. An ultrasound scan is a radiological test where sound waves are used to create pictures of the shoulder tendons. The ultrasound scan shows more than the bones of the shoulder; x-rays are usually normal.