Adhesive capsulitis, also called frozen shoulder, is a painful condition. It results in a severe loss of motion in the shoulder. It may follow an injury, or it may arise gradually with no injury or warning.
This guide will help you understand
- what causes frozen shoulder
- what tests your doctor will do to diagnose it
- how you can regain use of your shoulder.
What part of the shoulder is affected?
The shoulder is made up of three bones: the scapula (shoulder blade), the humerus (upper arm bone), and the clavicle (collarbone). The joint capsule is a watertight sac that encloses the joint and the fluids that bathe and lubricate it. The walls of the joint capsule are made up of ligaments. Ligaments are soft connective tissues that attach bones to bones. The joint capsule has a considerable amount of slack, loose tissue, so the shoulder is unrestricted as it moves through its large range of motion.
In frozen shoulder, inflammation in the joint makes the normally loose parts of the joint capsule stick together. This seriously limits the shoulder’s ability to move, and causes the shoulder to freeze.
Why did my shoulder freeze up?
The cause of frozen shoulder is largely a mystery. One theory is that it may be caused by an autoimmune reaction. In an autoimmune reaction, the body’s defense system, which normally protects it from infection, mistakenly begins to attack the tissues of the body. This causes an intense inflammatory reaction in the tissue that is under attack.
No one knows why this occurs so suddenly. Frozen shoulder may begin after a shoulder injury, fracture, or surgery. It can also start if the shoulder is not being used normally. This can happen after a wrist fracture, when the arm is kept in a sling for several weeks. For some reason, immobilizing a joint after an injury seems to trigger the autoimmune response in some people.
Frozen shoulder has also been known to occur after surgery unrelated to the shoulder, even after recovering from a heart attack. Other shoulder problems like bursitis, rotator cuff tears, or impingement syndrome can end up causing a frozen shoulder. Doctors theorize that the underlying condition may cause chronic inflammation and pain that make you use that shoulder less. This sets up a situation that can create frozen shoulder. Usually, the frozen shoulder must be treated first to regain its ability to move before the underlying problem can be addressed.
What are the symptoms of frozen shoulder?
The symptoms of frozen shoulder are primarily shoulder 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 yourself or someone else is trying to move the arm for you. There comes a point in each direction of movement where the motion simply stops, as if something is blocking it. At this point, the shoulder usually hurts. The shoulder can also be quite painful at night. The tightness in the shoulder can make it difficult to do regular activities like getting dressed, combing your hair, or reaching across a table.
What tests will my doctor run?
The diagnosis of frozen shoulder is usually made on the basis of your medical history and physical examination. One key finding that helps differentiate a frozen shoulder from a rotator cuff tear is how the shoulder moves. With frozen shoulder, the shoulder motion is the same whether the patient or the doctor tries to move the arm. With 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.
Simple X-rays are usually not helpful. An arthrogram may show that the shoulder capsule is scarred and tightened. The arthrogram involves injecting dye into the shoulder joint and taking several X-rays. In frozen shoulder, very little dye can be injected into the shoulder joint because the joint capsule is stuck together, making it smaller than normal. The X-rays taken after injecting the dye will show very little dye in the joint.
As your ability to move your shoulder increases, your doctor may suggest tests to rule out an underlying condition, such as impingement or a rotator cuff tear. Probably the most common test used is magnetic resonance imaging (MRI). An MRI scan is a special imaging test that uses magnetic waves to create pictures that show the tissues of the shoulder in slices.
The MRI scan shows tendons and other soft tissues as well as the bones.
Colorized to illustrate soft tissues revealed in MRI