Types of Frozen Shoulder
There are two main types of frozen shoulder, Idiopathic (Primary) and Secondary Frozen Shoulder. Which type of frozen shoulder you have is important because the choice of treatment, the length of treatment, and the response of treatment can be very different between idiopathic and secondary frozen shoulder.
Some Patients who get a frozen shoulder do not have an injury and do not have a systemic disease such as diabetes. This type is called idiopathic (or primary) frozen shoulder. Idiopathic means there is known cause for frozen shoulder. In general, idiopathic frozen shoulder takes longer to treat than secondary frozen shoulder.
Early Stages of Frozen Shoulder
The early stages of frozen shoulder are caused by inflammation. The lining of the joint becomes inflamed, and this causes pain.
Very early in the process, the loss of motion is mostly the result of pain from inflammation. This pain inhibits normal function of the muscles. Pain fibers in the joint send signals to the surrounding muscles that there is inflammation. Those muscles will involuntarily contract to prevent the joint from moving and causing further pain. This is a common protective reflex of the muscles to injury around any large joint.
Late Stages of Frozen Shoulder
In the later stages of frozen shoulder, the inflammation will begin to cause the lining of the joint to thicken with fibrosis tissue. This thick scar tissue replaces the normal elastic tissue. When this happens, motion is lost because the joint lining is scarred and contracted.
Frozen Shoulder Impingement Zone
Normal motion usually preserves the elasticity of the lining of the joint and prevents fibrosis from thickening the joint lining. However, in frozen shoulder, normal motion is restricted, so fibrosis increases. Normal motion also maintains constant fluid movement in the joint. This fluid movement is very important for the nutrition and general health of the joint.
How can frozen shoulder be treated?
The first goals of treatment are to interrupt the inflammation and restore normal joint motion as soon as possible. This will reduce the fibrosis in the lining of the joint and restore normal fluid movement.
Using anti-inflammatory medicines interrupts inflammation. In order to deliver a concentrated dose of anti-inflammatory medicine to the joint, it is often best to have that medicine injected directly into the joint. This is the most effective way to relieve pain and interrupt inflammation.
When an injection is necessary, it should be performed as early as possible. This is because if it is performed in the very early stages of a frozen shoulder, it can quickly and completely restore normal motion. If it is performed in the later stages of a frozen shoulder, it is very effective at relieving pain, but restoring motion will be more difficult. When pain is reduced by the injection, it is easier for patients to perform the necessary stretching exercises and physical therapy that is required to restore motion. It is simply difficult to stretch the shoulder effectively when it hurts.
This is why, for the majority of patients, the most effective treatment is the injection followed by starting physical therapy and a home stretching program. Most patients in the early stages of a frozen shoulder will show significant improvement with treatment in three to six weeks.
In patients who do not make satisfactory improvements towards restoring normal motion, I often order an MRI to look for a rotator cuff tear.
Some patients will require a manipulation under anesthesia to get the shoulder moving. This is a stretching of the shoulder in the operating room while the patient is asleep and the muscles are relaxed. This is a very effective way to stretch the fibrosis/scar tissue and restore normal motion. Often at the same time, the arthroscope is used to release scar tissue and/or repair any tears in the rotator cuff. This is done as an outpatient procedure in a surgery center.