A tendon is a thick, fibrous cord that attaches muscle to bones. (By contrast, a ligament attaches one bone to another bone.) Because of the tendons and muscles, we are able to move our bodies.

When a tendon becomes irritated, the condition is called tendonitis. Because tendonitis is associated with overusing a joint, it's sometimes called tennis elbow, golfer's elbow, or swimmer's shoulder. As people get older, they are more likely to experience tendonitis. Improper technique in sports activities can also increase the stress on tendons.

A person with tendonitis will feel pain, tenderness or swelling outside a joint. Virtually any joint in the body may be affect. Common joints where tendonitis occurs are the shoulder (rotator cuff tendonitis), elbow or knee (patellar tendonitis). But it can also occur in the hip, heels (Achilles tendonitis) and wrists.

Diagnosing Tendonitis

Tendonitis can usually be diagnosed during a physical examination by a doctor. Because tendons are soft tissues, not bones, X-rays aren't usually helpful. (A doctor may order an X-ray, however, if there might be a chance that another condition is causing the symptoms.) A magnetic resonance imaging (MRI) scan can show tears or weakness in the tendon. An MRI is not usually needed, though. If a condition such as rheumatoid arthritis is suspected, a doctor may order a blood test.

Treating Tendonitis

In many cases, tendonitis goes away when the joint is given rest. Ice and nonsteroidal anti-inflammatory drugs may help reduce the pain and swelling.

Sometimes corticosteroids are injected around a tendon to relieve the pain and swelling. There is a possibility of side effects. If these drugs are injected directly into the tendon, they may cause it to rupture. Getting these shots regularly may weaken the tendon.

Physical therapy to strengthen the muscles that support the joint and to stretch the tendon may be helpful.

But if the tendonitis is severe, the tendon may rupture or tear. If the tendon becomes scarred, it may catch in the small spaces of a joint. When this happens, the joint locks in one position. An example of this is trigger finger. Then surgery may be needed.

Surgery can be done to repair tears. Sometimes damaged tendons are removed to promote the growth of more healthy tissues.