Shoulder Stability

However, because of this large range of motion that the shoulder can perform, injuries to this area are more likely possible, which can lead to instability. Shoulder instability occurs when the head of the upper arm bone is forced out of the shoulder socket. This action can result from overuse over many years; a sudden, unexpected injury; or from genetics (heredity). In its more serious form, it is called chronic shoulder instability.

The shoulder consists of three bones: the clavicle (collarbone), the humerus (bone in upper arm), and the scapula (shoulder blade). A shallow socket, called the glenoid socket, is contained in the shoulder blade where the ball (head) of the upper arm bone resides. The ball remains centered in the glenoid socket with strong connective tissue—what is called the shoulder capsule. This bone and connective tissue, along with muscles and ligaments, keep the shoulder stable.

However, the head of the upper arm bone can be forced out of the shoulder socket from a sudden injury, such as from a sporting activity. It can also be forced out from long-term overuse, such as repeated use as a swimmer, tennis player, or other such athlete. It can also be forced out due to genetics; that is, from being born with loose ligaments around the shoulder.

The head of the upper arm can come out only partially from the socket. This condition is called shoulder subluxation. In other cases, the dislocation can be a total one. A complete dislocation means the ball comes all the way out of the socket. This condition is called shoulder dislocation. When this happens repeatedly, the ligaments, tendons, and/or muscles around the shoulder have become loose or torn. This causes the shoulder to become loose, and it can easily slip out of place—what is called chronic shoulder instability. Once chronic shoulder instability is present, it is difficult to maintain the centered position of the arm bone in the shoulder socket. Consequently, shoulder dislocations happen frequently.

There are three frequent situations that cause the shoulder to become unstable. These are:

Common symptoms of chronic shoulder instability include:

If having problems with a shoulder that is unstable, visit the family doctor or other such medical professional. This trained medical person will analyze past medical history and the current symptoms involving the shoulder. Certain movements may be asked by the doctor to determine if looseness is present in the shoulder.

The doctor is likely to order an imaging test to help confirm the diagnosis. Such tests as x-ray scans and magnetic resonance imaging (MRI) scans may be used to show any injuries to the bones and tissues around the shoulder, along with any problems with the ligaments and tendons in that area.

Instability in the shoulder is usually first treated with nonsurgical methods. These include modifications in lifestyle, activities that directly cause shoulder problems. A nonsteroidal anti-inflammatory medication, such as aspirin and ibuprofen, will help to reduce the pain and swelling. The application of ice immediately after the injury will help, too.

If warranted, physical therapy and/or rehabilitation may help to strengthen the shoulder muscles. Specific exercises may help to bring increased stability to the shoulder. The exercises build strength within the muscles that perform internal and external rotation of the joint. If weights are used, they should be less than five pounds. At this time, the patient will usually be required by the doctor to wear a sling to support the injured shoulder.

If patients continue to be bothered by shoulder instability, then additional exercises may be recommended by the doctor to strengthen the muscles around the shoulder. These exercises will frequently include flexion (bending) and extension (extending) movements with weights ranging from 5 to 10 pounds, with the amount of weight depending on the injury's severity. Stretching exercises are also recommended to regain the full range of motion within the joint. In some cases, cortisone injections may be recommended. At this point, a sling may or may not be necessary.

As the injured area recovers, the patient should eventually regain full range of motion within the shoulder. Therapy usually concludes at this point. At the end of therapy, regular movements should be possible, such as those that initially caused the shoulder instability. However, while therapy is nearly finished, the patient should continue to perform exercises at home that increase muscle strengthening and mobility. Exercises should consist of weights with a minimum of 15 pounds.

In more serious cases, such as chronic shoulder instability, the doctor may recommend surgery to repair torn or stretched ligaments in the shoulder. Arthroscopic surgery is one surgical method. Small instruments and incisions are used to look inside the shoulder to pinpoint the problem. For instance, if the capsule of the shoulder has been injured an arthroscopic procedure is performed called thermal capsular shrinkage. In the procedure, a heated probe is inserted to shrink the capsule so it secures more tightly into the tissue. In simple surgical cases, this minimally invasive surgery may be the better option to choose.

However, when the surgery involves complex procedures, then open surgery is most likely the better answer. Open surgery involves making a large incision over the shoulder and repairing the injured parts while the patient is unconscious. Sometimes a procedure called Bankart repair is performed to fix ligament tears around the shoulder. After the surgery, the shoulder will in most cases be entirely immobile so the healing process can proceed as fast as possible. Once the doctor recommends the shoulder can be moved, a rehabilitation program may be set up to help strengthen the shoulder ligaments. This will also help to improve the shoulder's range of motion.

The prognosis of further joint dislocation in young people is usually quite high, but the chance of such continuing dislocation becomes lower as one ages. At any age, the risk of further dislocations is quite possible. In addition, risks of further bleeding and injuries to the blood vessels, incorrect healing, infection, and nerve damage are always possible.

The prevention of shoulder instability includes maintaining strength within the rotator cuff and the shoulder blade. Exercises that build and maintain muscle strength in those areas helps to keep the shoulder stable. In addition, learning the correct techniques when performing repetitious tasks or actions, such as throwing, helps to minimize the chances of shoulder instability.

William A. Atkins, BB, BS, MBA