Rotator cuff injury

The rotator cuff is a group of muscles and tendons (the tissue that connects muscles to bones) that surrounds the shoulder joint, much like a cuff surrounds the end of a shirt sleeve. The rotator cuff gives the arm a large range of motion. Rotator cuff injuries can range from simple strains to varying degrees of tears in the muscles or tendons.


Anatomy
The shoulder is a complex joint. The upper arm bone (humerus) meets the shoulder in a shallow socket called the glenohumeral joint. This shallow socket is part of the shoulder blade bone or scapula, which serves as the anchor for the muscles of the rotator cuff. Four muscles and their tendons make up the rotator cuff. These muscles stabilize the shallow joint of the shoulder and connect the scapula and humerus bones. During shoulder movement, the rotator cuff holds the humerus in the shoulder socket. As the shoulder joint moves, the rotator cuff and bursa (lubricating tissue) slide beneath the acromion (a part of the scapula bone on top of the shoulder). Contraction of the shoulder muscles pulls on the rotator cuff tendons to create movement.

Causes/associated factors
Rotator cuff injuries are less common in people under age 40, except as a result of repetitive overhead activities or acute trauma. With age, however, the risk of developing this type of shoulder problem increases. Years of normal movement may break down the tendons. This wear and tear can make you prone to tendinitis (inflammation of the tendons), tendinosis (degeneration of the tendons) or bursitis (inflammation of the lubricating tissue). Bone spurs (sharp growths of bone) may develop on the acromion and further irritate the rotator cuff. If one part of the joint or tissue is squeezed or compressed with another, the rotator cuff may become impinged (compressed due to inflammation). If the rotator cuff is impinged for a long time, the tendons become weak and are more likely to tear after a minor strain or injury. Even then, partial tears are more common than complete tears.
Rotator cuff injuries are most likely to happen:

during unusually vigorous exercise or work activities
during contact sports
while swimming, golfing, playing overhead racquet sports, such as tennis, or throwing repetitively, as in baseball and basketball
during any other activity that requires forward elevation of the arm or overhead movement, such as painting or carpentry
when falling directly on your shoulder or using your arm to break a fall
when lifting objects that are too heavy

Signs/symptoms
Symptoms associated with rotator cuff injuries may begin suddenly with an injury or develop gradually over time. You may notice shoulder pain or discomfort, which may become worse when you lift your arm overhead and at night, especially when you lie on your shoulder. Shoulder and arm weakness are also common, as well as loss of shoulder movement. Often, the arm can't be lifted forward, outward or overhead.
After a few weeks, the shoulder joint can become very stiff and difficult to move if it's rested too long. This condition is known as frozen shoulder.

It's important to note that shoulder pain is not always caused by a shoulder problem. Sometimes the pain is referred from other areas of the body, such as the liver, gallbladder, heart or cervical spine, or from other conditions, such as an ectopic pregnancy (when the fertilized egg implants itself outside the uterus) or an injury to the spleen.


Diagnosis
The doctor will ask questions about your medical history and examine your shoulder. For an accurate diagnosis, you may need one or more of the following tests:
An X-ray can help the doctor study the bones in your shoulder and detect dislocations, fractures or bone spurs. An X-ray may not be able to show the cause of shoulder weakness, however.
An ultrasound (using sound waves to create images of internal body parts) can help the doctor confirm the presence and severity of a rotator cuff tear.
An arthrogram (a series of X-rays taken after dye is injected into the shoulder joint) can also be used to detect tears.
Computed tomography (CT scan; a computer-generated, cross-sectional picture of internal body parts) or magnetic resonance imaging (MRI, an imaging technique based on computer analysis of the body's response to a magnetic field) can help the doctor evaluate soft tissue injuries in the shoulder joint and rotator cuff.

Treatment
Most people with minor rotator cuff injuries or shoulder pain recover with conservative treatment. The doctor may ask you to temporarily immobilize your arm in a sling. You may also want to try an ice pack or apply moist heat to your shoulder. To ease pain and inflammation, the doctor may suggest anti-inflammatory medications or cortisone injections. Sometimes, physical therapy treatments may be needed.
As the shoulder heals, your doctor will usually advise a progressive exercise program to improve the strength of the shoulder muscles and help prevent further injury. If the shoulder symptoms don't clear up within several months, further treatment may be needed.

Surgery
Generally, surgery is only suggested if you:

have significant pain and dysfunction that doesn't respond to several months of conservative treatment
repeatedly dislocate an unstable joint
have a complete tear of the rotator cuff
Before recommending surgery, the doctor will consider the severity of your injury and the functional level needed for your shoulder, as well as your age, health status and occupation. Because so many surgical options are available, you may want to seek a second opinion. Before making a decision, make sure you understand the risks, benefits and expected outcome of the surgery.

When done by experienced orthopedic surgeons, both arthroscopic and open repair shoulder surgeries generally have good to excellent results. It may be difficult to restore full function if the defect is chronic and not related to a major injury, however. Some people only partially regain their former level of strength or joint function.

Arthroscopic repair
Arthroscopic procedures begin with a few small incisions in the shoulder. Then, using an instrument called an arthroscope and other surgical tools, the doctor views the inside of the joint and repairs the damaged tissues. Arthroscopy generally has a short recovery time. You'll be able to return to normal activity more quickly than with other procedures. In some cases, arthroscopy is used as a diagnostic tool (the joint is viewed with the arthroscope but no repairs or other procedures occur).

Open repair
Some rotator cuff tears are too large to be repaired arthroscopically. An open repair requires a larger incision, which also means more time for healing and rehabilitation.

Postsurgical care
A period of rest and immobilization will help your shoulder heal properly. Then, you'll need to strengthen the muscles with exercise. Depending on the type of surgery and your physical condition, it may take up to six months or more before you regain full strength and range of motion. People who have chronic tears may be asked to avoid heavy lifting or overhead work to reduce the risk of tearing the tendon again.


Complications
Scar tissue and lack of use can lead to stiffness and decreased range of motion. Repeat tears may also occur.

Pregnancy-specific information
Rotator cuff injuries during pregnancy appear to have no harmful effect for mother or baby. Be sure to check with your doctor before taking any over-the-counter or prescription pain medication, however.

Senior-specific information
The risk for developing a rotator cuff injury increases with age due to normal wear and tear on the tendons and muscles. Inactivity can contribute to reduced muscle tone and strength, which increases the risk of injury when you use your shoulder. Inactivity can also lead to a condition known as frozen shoulder.

Prevention
Here are some tips to help you prevent rotator cuff injuries.
Maintain physical fitness. Stretching and strengthening exercises for the shoulder are especially helpful. Remember to warm up before you exercise.

Reduce repetitive movements. Many industries set limits on how much time workers can spend on tasks that require carrying overhead loads. It may be helpful to adjust the angle of your work and change your posture.

To decrease the force of loads lifted by your arms, use lightweight, counterbalanced, low-vibration tools.