Shoulder Instability

The shoulder is the most flexible joint in the body. But it does have limits. If the joint is pushed past these limits, the shoulder joint may move too much. This is called shoulder instability.

The shoulder is a shallow ball-and-socket joint. The humeral head is the ball of the top of the upper arm bone (humerus). The glenoid is a shallow socket on the shoulder blade. The humeral head rests on the glenoid and is held in place by strong tissues. These include:

• Labrum. This is a circle of cartilage. It covers the rim of the socket.

• Capsule. This is a sheet of ligaments and other tough tissues. It encloses the joint and connects the ball to the socket.

• Rotator cuff. This is a group of four muscles and tendons. These stretch between the ball and shoulder blade.

Shoulder instability can occur when any of these structures are weakened or torn, and the ball doesn’t stay centered in the socket. Multidirectional shoulder instability means the ball moves too far in more than one direction (forward, back, or down). This extra movement can lead to discomfort, pain, and problems using the shoulder.

The head of the arm bone (humerus) rests in a socket (glenoid), much like a golf ball fits on a tee. Parts of the joint called stabilizers hold the humeral head and glenoid together. These include a sheet of ligaments and other tough fibers called the capsule. This encloses the humeral head and glenoid.

The leading cause of instability is an injury that forces the humeral head out of its socket. If the humerus pushes completely out of the socket, it’s called dislocation. If it only pushes partially out, it’s called a subluxation. In both cases, the injury stretches or tears fibers in the capsule. It can also damage other parts of the joint. This makes the humeral head more likely to slip out of the glenoid again.

Chronic Shoulder Instability

If you have loose shoulder joints, you may also have what’s called chronic shoulder instability. This means your shoulder joint is dislocated more than once. Or it may feel as though it’s going to pop out of the socket.

Chronic shoulder instability can be painful and make it hard to do everyday activities, such as reaching for something overhead or combing your hair.

If you have chronic shoulder instability, physical therapy and specific exercises can help make your shoulder more stable. Surgery may also be an option.

With chronic shoulder instability, it’s important to avoid activities that may cause your shoulder to dislocate. And you need to be careful not to overdo it when you exercise your shoulder. Too much activity may make your shoulder instability worse.

A serious injury can lead to shoulder instability. Or the problem may happen slowly over time. Causes include:

• Having loose joints (being "double-jointed").

• Repeated overhead motions, such as throwing or swimming.

• Repeated shoulder injuries.

• Dislocating the shoulder joint. This means the ball is forced out of the socket.

• Fracturing part of the shoulder joint.

These can include one or more of the following:

• Feeling that the shoulder slips out of place.

• Discomfort or pain when using the shoulder. This often occurs when making an overhead movement, carrying heavy objects, or pushing heavy doors.

• Shoulder weakness.

• Catching, popping, or grinding in the joint.

• Trouble using the shoulder or arm.

The goal of treatment is to reduce pain and improve shoulder function.

• Physical therapy. This can help restore strength and stability to your shoulder. Some treatments help reduce pain. Physical therapy for this condition often takes several months.

• Over the counter or prescription medicines. These help relieve pain and swelling. NSAIDs (nonsteroidal anti-inflammatory drugs) are the most common medicines used. Medicines may be prescribed or bought over the counter. They may be given as pills. Or they may be put on the skin as a gel, cream, or patch.

• Surgery. If physical therapy isn’t enough to heal your shoulder, you may need surgery to repair the tissues that stabilize the joint. This surgery often makes the shoulder tighter than before, so you may lose a small amount of flexibility.

Your doctor or physical therapist will likely recommend a series of exercises to help stretch and strengthen the muscles and ligaments around your shoulder joint. These exercises can help make your shoulder more stable and less likely to dislocate.

Start by doing these exercises 2 to 3 times a day. As your shoulder becomes stronger, you can do them 3 to 5 times a day. Repeat each exercise 10 to 15 times in a single session or as many times as you can without pain.

Please consult your physician or physical therapist before performing any of the following exercises, as you may need certain variations of each specific to your shoulder condition.

1. Pendulum swings: Let your arm hang down in front of your body, with your elbow bent at 90 degrees. Use your good arm to swing your affected arm in small circles. Do this for 30 seconds, then switch directions.

2. Shoulder blade squeezes: Squeeze your shoulder blades together, as if you’re trying to touch them in the middle of your back. Hold for 5 seconds, then relax.

3. Arm raises: Slowly raise your affected arm out to the side and up overhead, keeping your elbow straight. Stop when you feel a stretch in the front of your shoulder. Lower your arm and repeat.

4. External rotations: Sit or stand with a towel rolled up under your armpit. Rest your elbow on a table or chair so that your hand is pointing toward the ceiling. Keeping your elbow in place, rotate your hand outward until you feel a stretch in the back of your shoulder. Return to the starting position and repeat.

5. Internal rotations: Sit or stand with a towel rolled up under your armpit. Rest your elbow on a table or chair so that your hand is pointing toward the floor. Keeping your elbow in place, rotate your hand inward until you feel a stretch in the front of your shoulder. Return to the starting position and repeat.

6. Doorway stretches: Stand in a doorway with your arms at 90-degree angles, elbows bent and hands on the door frame. Step forward with one foot and lean forward until you feel a stretch in the chest and front of your shoulders. Hold for 30 seconds, then switch sides and repeat.

7. Backward arm swings: Start by holding a light dumbbell in your affected hand. Stand with your feet shoulder-width apart and your knees slightly bent. Swing your arm backward and up until you feel a stretch in the front of your shoulder. Return to the starting position and repeat.

8. Side-lying external rotations: Lie on your side with a pillow under your head and a light dumbbell in your affected hand. Bend your elbow so that your hand is pointing toward the ceiling. Keeping your elbow at 90 degrees, rotate your hand outward until you feel a stretch in the back of your shoulder. Return to the starting position and repeat.

9. Prone horizontal abductions: Lie facedown on a table or bed with a pillow under your head and a light dumbbell in your affected hand. Keeping your elbow straight, raise your arm out to the side until it’s in line with your body. Return to the starting position and repeat.

10. Seated internal rotations: Sit on a chair with a light dumbbell in your affected hand and your elbow bent at 90 degrees. Rest the back of your forearm on your thigh. Rotate your hand inward until you feel a stretch in the front of your shoulder. Return to the starting position and repeat.

11. Seated external rotations: Sit on a chair with a light dumbbell in your affected hand and your elbow bent at 90 degrees. Rest the back of your upper arm on the seat of the chair and rotate your hand outward until you feel a stretch in the back of your shoulder. Return to the starting position and repeat.

12. Prone flies: Lie facedown on a table or bed with a pillow under your head and a light dumbbell in each hand. Keeping your elbow straight, raise your arms out to the sides until they’re in line with your body. Return to the starting position and repeat.

If you have chronic shoulder instability, these exercises may not be enough to prevent further dislocations. In this case, you may need to wear a brace or sling to support you until the shoulder muscles and ligaments heal. Surgery is also an option for chronic shoulder instability.