Shoulder Instability Fundamentals

The ball and socket joint of the shoulder is held together by ligaments, muscles and bones. When these structures become over stretched or injured, the shoulder becomes unstable.

The most common cause of shoulder instability is trauma. When a dislocation occurs, the restraining structures of the joint are injured. Contact sports such as football and downhill skiing are common causes of shoulder dislocation, and the condition occurs frequently among young athletes. However, household trauma such as falling down stairs, off a bicycle or while walking along the sidewalk can be damaging enough to dislocate a shoulder. Additionally, some people have a genetic predisposition to shoulder instability. Finally, repetitive activities such as throwing sports and swimming can gradually overstretch the ligaments, resulting in instability and dislocation. Fractures of the shoulder’s ball and socket may occur, which also contribute to shoulder instability.

Athletes can take steps to prevent shoulder instability. Maintaining good rotator cuff and shoulder blade strength is important in decreasing the risk of ligament injury. Learning correct techniques of pitching and throwing is also important.

What are the symptoms?

The most characteristic symptom of shoulder instability is a sense that the shoulder is about to come out of place or that the shoulder has jumped back into its socket. This sensation may or may not be accompanied by pain, but it is typically uncomfortable. Occasionally, a person may feel numbness or a tingling down the arm.

In addition, the patient may experience clicking, catching or looseness of the shoulder with daily activities and particularly with sports that require overhead throwing or swimming.

Sometimes, the ball of the joint will separate completely from socket, and the ball will not spontaneously fall back into place. Severe pain, deformity of the shoulder and a sense of paralysis of the arm may occur as a result. Manipulating the arm into place may require physician assistance.

How is it treated?

The shoulder joint should be put back into place promptly. Immediately after the injury, ice and a sling make the patient more comfortable. In a young and athletic person the chance of redislocation is usually high. This risk decreases with age.

Often, shoulder instability is subtle and repeated examinations are necessary to establish and confirm the diagnosis. It is particularly important for the physician to examine the uninvolved shoulder and to compare the patient’s normal ligament status to the symptomatic shoulder when coming to a decision regarding treatment.


Immediately after injury, the patient should ice and rest the shoulder in a sling. X-rays will help to determine whether any bone injury has occurred as a result of the dislocation. Following a period of a few days’ rest, the patient should begin an exercise program to strengthen the shoulder muscles.
Most patients wear the sling for one to two weeks to decrease acute shoulder pain. After the sling is removed, the patient should avoid extremes of motion over the next four weeks. After this period of time, a progressive rehabilitation program can begin.


If there are continuing symptoms that interfere with sleeping, daily activities, work, or sports participation, surgical stabilization may be required.

The goal of shoulder surgery involves reattaching torn ligament tissue to shorten or tighten the stretched ligament tissue. The surgeries performed can be done by either arthroscopic or open methods, but the goal of the surgery is the same.

After surgery, the arm is kept in a sling for four to six weeks. You are encouraged to keep the elbow/wrist and hand mobile during this time while the tissues in the shoulder heal into place. Physical therapy to gradually regain range of motion and strength is commenced after surgery.

Treatment Guide

Reviewed by a Cleveland Clinic medical professional.

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