Tendons are tough, flexible, fibrous bands of tissue that connect muscles to bones. When tendons become inflamed, irritated or suffer microscopic tears, the condition is called tendonitis. Tendons can be small, like the delicate, tiny bands in the hands, or large, like the heavy, ropelike cords that anchor the calf or thigh muscles. In most cases, the cause of tendonitis is unknown; when a cause can be identified, the condition usually happens for one of two reasons:

• Overuse � A particular body motion is repeated too often.
• Overload � The level of a certain activity, such as weightlifting, is increased too quickly.

Rarely, tendonitis is caused by an infection, such as gonorrhea. Tendonitis is most common in the shoulder, elbow, knee, wrist and heel, although it can happen anywhere in the body. For uncertain reasons, tendonitis is also common in people with diabetes. In recent years, a rare cause of tendonitis (or other tendon disease, including rupture) has been recognized: the use of certain antibiotics, including ciprofloxacin or levofloxacin. Why this happens is unknown.

Tendonitis in the shoulder � The most common form of tendonitis in the shoulder is rotator cuff tendonitis. It involves the tendon of the supraspinatus muscle, which attaches to the upper portion of the upper arm bone (humerus) at the shoulder joint. Less commonly, the tendon of the infraspinatus muscle is affected. In most cases, the supraspinatus tendon is injured by overuse, typically in an occupation or sport that requires the arm to be elevated repeatedly. People at risk include carpenters, painters, welders, swimmers, tennis players and baseball players. The average patient is a male laborer older than 40, and the shoulder pain is on the same side as his dominant hand (for example, right shoulder pain in a right-handed person).

Tendonitis in the elbow � Two forms of tendonitis commonly involve the elbow: lateral epicondylitis and medial epicondylitis. Both are very common overuse injuries among athletes involved in throwing and racquet sports.

Lateral epicondylitis (tennis elbow) causes pain on the outer side of the elbow joint. This condition probably affects 40% to 50% of all adult athletes who play racquet sports. It also can be caused by any activity that repeatedly twists and bends the wrist, such as pulling weeds, using a screwdriver or even carrying a briefcase.

Medial epicondylitis (golfer's elbow) causes pain on the inner side of the elbow. It is a less common injury than tennis elbow and, despite its name, it is more likely to be related an occupation that requires repeated elbow movements (such as construction work) than to sports. When it does occur as a sports injury, medial epicondylitis can be triggered by repeatedly swinging a golf club or throwing a baseball.

Tendonitis in the knee � Jumper's knee, the most common form of knee tendonitis, involves either the patellar tendon at the lower edge of the kneecap or the quadriceps tendon at the upper edge of the kneecap. It is a common overuse injury, especially in basketball players and distance runners.

Tendonitis in the wrist � In the wrist, tendonitis commonly appears in the form of de Quervain's disease, a condition that causes pain in the back of the wrist at the base of the thumb. Although de Quervain's disease usually occurs in people who repeatedly grasp or pinch with the thumb, it sometimes develops during pregnancy or for no known reason.

Achilles tendonitis � This form of tendonitis affects the Achilles tendon, the large ropelike tendon attached to the heel bone at the back of the foot. Achilles tendonitis usually is caused by overuse, especially in sports that require running or repeated jumping, and it accounts for 15% of all running injuries. Achilles tendonitis also may be related to faulty running technique or to poorly fitting shoes, if the back of the shoe digs into the Achilles tendon above the heel. Less often, Achilles tendonitis is related to an inflammatory illness, such as ankylosing spondylitis, Reiter's syndrome, gout or rheumatoid arthritis.

Symptoms

In general, tendonitis causes pain in the tissues surrounding a joint, especially after the joint is used too much during play or work. In some cases, the joint may feel weak, and the area may be red, swollen and warm to the touch.

When tendonitis is caused by an infection such as gonorrhea, there may be other symptoms, including rash, fever, or a discharge from the vagina or penis.

Other symptoms vary according to which tendon is affected:

• Rotator cuff tendonitis � Usually dull, aching shoulder pain that can't be tied to one location. It often radiates into the upper arm toward the chest. The pain is often worse at night and may interfere with sleep.
  
  
• Tennis elbow � Pain in the outer side of the elbow. In some cases, the painful area extends down to the forearm and wrist
  
  
• Golfer's elbow � Pain in the inner side of the elbow
  
  
• Jumper's knee � Pain below the kneecap and, sometimes, above it
  
  
• De Quervain's disease � Pain at the back of the wrist, near the base of the thumb
  
  
• Achilles tendonitis � Pain at the back of the heel or 2 to 4 inches above the heel

Diagnosis

After reviewing your medical history, including any previous joint injuries, your doctor will ask you specific questions about your pain:

• What does your pain feel like (sharp, dull, burning)?
• Where is your pain located? Is it limited to one area or does it spread away from the joint to involve a wider area on your arm, leg or hand?
• Do you have tingling, numbness or weakness?
• When did your pain start? Did it begin after a sudden increase in your work activities or exercise? Might it be related to any new sport or exercise that you've recently tried?
• What makes it feel better, and what makes it worse?
• Does the pain disappear when you rest the area, or is it present even at rest?
• Have you had unprotected sex?

During the physical exam, your doctor will look for tenderness, swelling, redness, muscle weakness and limited motion in the area of the sore tendon. Your doctor also may ask you to move in certain ways, such as raising your arm above your head or bending your wrist. These moves may hurt, but they are very important to help your doctor figure out which tendon is affected. In most cases, diagnosis can be made based on your medical history and symptoms, together with your occupational and sports history and the results of your physical examination.

Some people may need blood tests to look for other causes of inflammation around the joints, such as gout or rheumatoid arthritis. X-rays also may be taken to confirm that there is no fracture, dislocation or bone disease. In people with Achilles tendonitis, ultrasound or magnetic resonance imaging (MRI) scans may be used to help evaluate the extent of tendon damage.

Expected Duration

Depending on the location and severity of tendonitis, symptoms may last for a few days or for several weeks. If there is continued overuse or aggravation of the injured site, pain may worsen and persist for several months.

Prevention

In many cases, tendonitis can be avoided by taking a few simple precautions. Some helpful strategies include:

• Always warm up before beginning strenuous exercise.
  
  
• If you want to intensify your exercise level, do it gradually.
  
  
• Be careful about the "no pain, no gain" approach. It is usually hard to distinguish between an ache that indicates you're building strength and an ache that means you injured a tendon.
  
  
• Avoid activities that require prolonged periods of reaching over your head, such as painting the ceiling. If you must do this kind of work, take frequent breaks.
  
  
• Wear shoes that fit properly, especially if you participate in a sport that requires a lot of running, such as track, cross-country or basketball.
  
  
• If you are active in sports or exercise technique, ask your coach or trainer for guidance. A doctor who specializes in sports medicine may be helpful as well.
  
  
• For people with medial or lateral epicondylitis related to racquet sports, changing to a racquet with a larger head may help to prevent re-injury, as long as the new racquet is not heavier than the original. Some specialists believe that this type of racquet cuts down on the transmission of vibrations to the arm.
  
  
• Tendonitis caused by gonorrhea can be prevented by abstinence or by practicing safe sex.

Treatment

The quicker your tendonitis is treated, the sooner you'll recover full strength and flexibility. Your doctor first may recommend that you apply ice packs to the painful area for 20-minute periods, three or four times a day. You also should ice the area immediately after any activity that aggravates your pain (such as tennis, running, etc.) To relieve pain and swelling, your doctor may suggest that you take ibuprofen (Advil, Motrin and others), aspirin or another nonprescription anti-inflammatory medication, usually for several weeks. You also will need to rest the area for a few days to a few weeks to allow your body to repair itself. For example, people with golfer's elbow usually need to rest the affected elbow for at least one month. If an infection is causing the tendonitis, an antibiotic is recommended.

Depending on the location and severity of tendonitis, you may need temporary splinting, bracing or a sling (for tendonitis in the upper extremity). However, it is important to keep moving the joint to avoid getting a stiff, or "frozen," joint.

For more serious cases of noninfectious tendonitis, your doctor may inject a corticosteroid drug or local anesthetic into the affected tendon. He or she also may refer you to a physical therapist for more specialized local treatments, such as deep heat treatments using ultrasound, friction massage or water therapy to improve joint mobility. The physical therapist also will guide you through a rehabilitation program that will help you to regain strength, motion and function. The length of time for rehabilitation varies depending on the type and severity of tendonitis. For example, it is usually at least two to six months for Achilles tendonitis and at least six months for epicondylitis.

Surgery is rarely needed to treat tendonitis. It is reserved for cases that do not respond to other types of treatment.

When To Call a Professional

Call your doctor whenever you have a significant joint problem, such as severe pain, redness or swelling or loss of joint function. Also, call your doctor if less-severe joint pain persists beyond a few days.

Prognosis

With proper treatment, the affected tendon usually recovers completely. However, incomplete rehabilitation or a hasty return to activity can slow the healing process or lead to re-injury.

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