All About the Shoulder

What is the shoulder joint and how does it work?

The shoulder is the most freely moving joint in the body. This ball-and-socket joint is made up of three bones:

• The clavicle or collarbone
• The scapula or shoulder blade
• The humerus or upper-arm bone

Your shoulder also contains two types of cartilage:

White articular cartilage on the ends of the bones

The labrum, a more fibrous type of cartilage around the shoulder socket

Why are shoulder injuries so common?

The shoulder is less stable than other joints because it can move in many different directions, yet must be strong enough to allow you to lift, push and pull. This makes the shoulder more prone to injury than other joints such as the hip.

What is the rotator cuff and how does it work?

The rotator cuff is a supporting structure of the shoulder. It is made up of a group of flat tendons surrounding the shoulder like a shirt sleeve cuff. These tendons, and the muscles connected to them, attach the arm to the shoulder and allow the arm to move.

What kinds of injuries and conditions can affect the shoulder?

• Overuse injuries
• Rotator cuff tears
• Rotator cuff impingement or tendinitis
• Shoulder dislocation
• Arthritis
• Frozen shoulder

What is the most common type of shoulder injury?

Overuse injuries are the most common type of shoulder injury. These injuries can result from:

• Repetitive throwing
• Overhead racquet sports
• Swimming
• Weightlifting
• Occupations requiring overhead lifting

What is rotator cuff impingement or tendinitis?

Painful rotator cuff impingement syndrome or tendinitis is caused by pressure on the rotator cuff from part of the shoulder blade when the arm is raised. In some cases, bone spurs can pinch the rotator cuff tendons. This condition can also limit shoulder movement.

How is rotator cuff impingement treated?

In most cases, rotator cuff impingement or tendinitis gets better with time, physical therapy, rest or cortisone injections. However, some patients who have continually aggravated their shoulder or have a severe rotator cuff injury end up tearing their rotator cuff.

Who is most likely to tear their rotator cuff?

Rotator cuff tears are most common in younger athletes and older adults—but they tear them for different reasons. Younger patients typically tear a rotator cuff through participation in active sports or traumatic injury.

Older people tear a rotator cuff due to loss of elasticity in the muscle and tendons of the shoulder. Even performing everyday activities can lead to rotator cuff damage.

Your genes may also affect your probability of tearing a rotator cuff. A study published in the May 2009 issue of The Journal of Bone and Joint Surgery found that people with relatives who have experienced rotator cuff tears have a greater risk of similar tendon tears themselves.

What types of shoulder injuries are common in younger athletes?

• Labrum tears. Athletes under age 45 are less likely to tear their rotator cuff; they end up tearing a cartilage in the shoulder called the labrum
• Recurrent dislocated shoulder. This is indirectly the same problem as a torn labrum. In younger athletes, the damaged cartilage or labral tissue allows the shoulder to dislocate, or literally pop out of the socket.

How can a shoulder dislocation differ depending on the patient's age?

If you're under age 25, once you dislocate your shoulder, you have a very high likelihood of dislocating it again. You typically tear a ligament in your shoulder the first time you dislocate it—and it will probably pop back out.

About 85% of dislocated shoulders in young athletes will re-dislocate, no matter what non-surgical treatment is given. In this case, surgical repair is necessary.

What happens when older adults dislocate their shoulder?

If you're over 55 and you dislocate your shoulder, you're more likely than a younger athlete to fracture your shoulder or tear your rotator cuff. Consequently, you're less likely to have recurrent shoulder dislocations—but will likely need treatment for a broken shoulder or a torn rotator cuff.

Can calcium deposits affect the shoulder?

Yes. Calcific rotator cuff tendinitis occurs when you get calcium deposits in your rotator cuff—almost like getting kidney stones in your shoulder. Calcium deposits in the rotator cuff occur most commonly in women ages 35 and 65, but may occur in men as well.

Can calcium deposits damage the shoulder?

Some small calcium deposits don't cause any symptoms. But when a calcium deposit gets beg enough to pinch between the bones when you raise your shoulder, you will feel pain. Some calcium deposits can cause erosion that can destroy part of the rotator cuff tendon.

How are shoulder calcium deposits treated?

When shoulder calcium deposits cause pain and inflammation, they can be treated conservatively with ice packs, rest in a sling and oral anti-inflammatory medications.

What if conservative treatment doesn't work for calcium deposits?

If the calcium deposits in your shoulder are still causing you pain, arthroscopic surgery can be performed to break up and remove the deposits.

How can arthritis affect the shoulder?

Arthritis is less likely to affect the shoulders than the weight-bearing joints such as the hips and knees.

• Osteoarthritis, or wear-and-tear-arthritis, is the most common form of shoulder arthritis. This disease causes a wearing away of the protective cartilage in the shoulder joint, leading to pain, stiffness and inflammation.
• Rheumatoid arthritis or RA, a systemic disease believed to be an autoimmune disorder, can also affect the shoulder. RA causes the lining of the joints to become inflamed, which, in time, can destroy the cartilage and bone.

Who is most likely to develop shoulder arthritis?

You may be at increased risk for shoulder arthritis if you have:

• Broken your shoulder in the past
• Worked in a job requiring a lot of overhead lifting
• Suffered a traumatic injury to your shoulder
• A family history of shoulder arthritis
• Had an overuse injury of the shoulder—due to sports or work

How is shoulder arthritis treated?

The first line of treatment for shoulder arthritis consists of conservative, non-surgical methods such as:

• NSAID s—either prescription or over-the-counter
• Physical therapy
• Cortisone injections to treat inflammation

Can the shoulder joint be replaced?

Yes. If conservative treatment methods do not relieve the pain and stiffness of shoulder arthritis, the Center for Orthopedics offers two types of shoulder replacement surgery:

• Reverse total shoulder replacement—a state-of-the-art procedure to reconstruct a shoulder that was previously thought to be non-operable—such as a shoulder with a rotator cuff tear, re-tear, deficiency, tendon rupture, severe fracture or advanced arthritis. This procedure is available at only a limited number of orthopedic practices in the U.S. The Center for Orthopedics' Robert Zanotti, MD, and Daniel Zanotti, MD, perform reverse total shoulder replacement surgery.
• Traditional shoulder replacement can be performed if you have an intact rotator cuff.

What is ‘frozen shoulder’?

Frozen shoulder, or adhesive capsulitis, is an inflammation of the ligaments that connect the shoulder bones and keep them properly aligned. This inflammation causes scar tissue and adhesions that severely restrict the range of motion in the shoulder joint. Frozen shoulder can cause considerable pain when trying to move the shoulder.

Who is most likely to develop frozen shoulder?

• Women age 40 and older, especially those with endocrine or thyroid problems
• Diabetics
• People with cardiovascular disease
• Women who have had breast surgery

Frozen shoulder can also be idiopathic—meaning you didn't do anything at all and your shoulder just gets progressively tighter.

How is frozen shoulder treated?

Frozen shoulder is treated with conservative therapy for the first four to six months. Treatments such as oral anti-inflammatory and pain medications and physical therapy can help ease the pain and regain a normal range of motion in the shoulder.

Can surgery help frozen shoulder?

If conservative therapy does not give relief, arthroscopic surgery can be performed to release the adhesions and allow normal shoulder movement.