Your shoulder joint is a ball-and-socket joint in which the rounded top of your upper arm bone (humerus) fits into a cup-shaped socket (glenoid) of the shoulder blade.
Shoulder instability is a condition that occurs when the muscles, ligaments and tendons that surround the shoulder joint loosen and do not keep the ball in the socket.
- If the joint is too loose, the head of the humerus may partially slide out of place. This is called subluxation, or the temporary, partial dislocation of the shoulder joint.
- If the ball of the upper arm bone slips completely out of the shoulder socket, this is called a shoulder dislocation. Because the shoulder is the most mobile joint in your body, it’s also the most frequently dislocated major joint in the body.
Shoulder dislocation is often caused by injury as a result of contact or fall-prone sport such as football, gymnastics, volleyball or downhill skiing, or trauma from an accident or fall. A severe initial dislocation can lead to chronic instability, leading to continued dislocations.
- Forward and downward dislocation: The most common types of dislocations, these usually result when you fall on your outstretched hand or on the shoulder itself
- Backward dislocation: This type of dislocation may be caused by a blow to the front of your shoulder, or if your upper arm is violently twisted
You are more likely to develop shoulder instability if you have had a prior shoulder dislocation, if you are a young athlete involved in sports such as volleyball, swimming and baseball that involve overhead motions, or if you have certain connective tissue disorders that contribute to loose joints (joint laxity, sometimes called double-jointedness)
It’s important to seek prompt medical attention if you think your shoulder is dislocated. In most cases, you can expect to regain full function of your shoulder within a few weeks. Once you’ve had a dislocated shoulder, however, your shoulder joint may become unstable and you are at higher risk of repeated dislocations.
Why Choose Cooper to Diagnose and Treat Shoulder Instability
Cooper has a board-certified and fellowship-trained shoulder specialist as well as three sports medicine specialists—all with extensive experience in diagnosing and treating shoulder instability, including shoulder dislocation. You can count on us for:
- Fast access: Our policy is to see sports-related injuries within 24 to 48 hours
- Advanced expertise: As South Jersey’s only tertiary care facility, we see the region’s most complex cases—a level of expertise you simply won’t find anyplace else in this area
- Personalized treatment: Treatment is based on your age, general health, lifestyle, and severity of symptoms, with a focus on restoring shoulder stability and preventing future dislocations
Shoulder Instability Causes and Risk Factors
There are three main causes of shoulder instability:
- Shoulder injury: A severe injury to the shoulder can stretch or tear the ligaments of the shoulder away from the bone, causing the shoulder to become unstable
- Repetitive strain: Repetitive overhead motion as in swimming, tennis, volleyball, construction or painting can cause shoulder ligaments to loosen, compromising shoulder stability
- Naturally loose ligaments: Some people have shoulder instability without a history of injury or repetitive strain due to naturally loose ligaments throughout the body (sometimes referred to as being “double-jointed”) or a connective tissue disorder
Some factors that can increase your risk of shoulder instability include:
- Age: The age group at highest risk of shoulder dislocation are males in their teens and 20s, particularly athletes
- Shoulder stress: Repetitive, overhead movements from activities such as swimming, tennis, baseball, painting can cause shoulder muscles and ligaments to weaken, stretch or tear over time, making the shoulder joint less stable
- Genetics: Certain hereditary conditions can affect the body’s connective tissues, causing lax (loose) ligaments and increasing the risk of shoulder instability and dislocation
Symptoms of Shoulder Instability
While symptoms vary from person to person, the most common symptoms of shoulder instability include:
- Pain caused by injury to the upper arm and shoulder
- Repeated partial or complete shoulder dislocations
- Repeated occurrences of the shoulder “giving out”
- A chronic sensation of the shoulder feeling loose, or slipping in and out of the joint
Athletes with instability often have the sensation that their shoulder is about to slip out of its socket when their arm is positioned to throw a ball or serve (as in racquet sports). Continued throwing can cause a tear to worsen, compromising the athlete’s ability to perform.
Symptoms of a shoulder dislocation include:
- Sudden onset of pain in the shoulder
- A pins-and-needles sensation or numbness (due to nerve or blood vessel damage)
- Loss of shoulder function
- Shoulder deformity
If you suspect a shoulder dislocation, seek medical attention immediately. Do not try to move the shoulder or manipulate the joint yourself because you may cause further damage.
Treating Shoulder Instability
Your doctor will take a thorough health history, perform a physical exam, and order appropriate tests, which will likely include diagnostic imaging, such as an x-ray.
Treatment for shoulder instability is tailored to your unique situation and may include:
- Shoulder reduction: This refers to the manual, non-surgical process of returning the head of your arm bone to its normal position in the socket of your shoulder blade after a shoulder dislocation. Depending on how much pain and swelling you have, your doctor may administer a muscle relaxant, sedative or anesthetic before manipulating your shoulder and arm bones. Once they’re back in place, severe pain improves right away.
- Immobilization: You may wear a special sling for a few days up to a few weeks post-injury to keep your shoulder from moving while it heals
- Rest and icing: Rest and applying ice to the affected area several times a day in the days after an injury will help reduce pain and swelling
- Medication: Your doctor may prescribe pain relievers and/or muscle relaxants to help keep you comfortable while your shoulder heals
- Physical rehabilitation: Once your sling is removed, you should begin a gradual physical therapy program aimed at restoring your shoulder joint’s range of motion, strength and stability
- Surgery: If nonsurgical approaches do not restore shoulder strength and stability, surgery may be indicated
Preventing Shoulder Dislocation
Once you’ve had a shoulder dislocation, you may be at higher risk of future dislocations. To help prevent this from happening, continue to perform the strength and stability exercises that your doctor and/or physical therapist have taught you. In addition:
- Take steps to avoid falls
- Wear appropriate protective gear when playing sports