Tendons are ropes of fibrous tissue that connect muscles to bones. It is this connection that permits joint motion. When muscles contract, they pull on the tendons which cause the bones to move. In order for tendons to glide they move inside a lubricated sheath of tissue that is lined with synovial tissue. This synovial tissue is the same type of tissue that lines the inside of joints. Tendonitis refers to a condition where the sheath through which a tendon glides becomes inflamed. This leads to severe pain. The pain usually gets worse with use of the affected joint. However, when tendonitis becomes severe, there may be pain at rest.

Since muscles and tendons surround most joints, tendonitis is rather common. The diagnosis of tendonitis is relatively simple for the experienced clinician. Genrally, the diagnosis is made by history and physical examination. In difficult diagnostic cases, magnetic resonance imaging is helpful in confirming the diagnosis.

Some of the more common types of tendonitis are:

Shoulder tendonitis. The tendons in the shoulder that are most often affected are the rotator cuff and the biceps tendon. The rotator cuff consists of four tendons that sit on top of the upper arm bone. The location of these tendons and the muscles they attach to are what give the shoulder such an expansive range of motion. Rotator cuff tendonitis may occur as a result of repetitive activity or tendon degeneration. Pain is felt with most movements and is located on the outside part of the shoulder. The biceps tendon allows the arm to be flexed at the elbow. Biceps tendonitis also occurs due to repetitive activity and pain is felt in the front of the shoulder. Shoulder tendonitis can be treated successfully with anti-inflammatory medication, physical therapy, and occasionally glucocorticoid injection.

Tendonitis in the elbow is usually located either on the outside and is called lateral epicondylitis or tennis elbow. It may also occur along the inside part of the elbow- medial epicondylitis. This is called golfer's elbow. Treatment consists of physical therapy, stretching and strengthening exercises, splints, and injections. Rarely, surgery is required.

Tendonitis in the wrist arises because of repetitive motion. A special type of tendonitis, called Dequervain's tendonitis, is felt on the out side of the thumb. Tendonitis in these areas is managed with glucorticoid injections and immobilization with a splint. Other physical therapy modalities may be helpful. Sometimes surgery is required. Tendonitis in the fingers can lead to catching of the fingers. This is termed "trigger finger." Trigger finger usually responds to injection but may require operative intervention.

Tendonitis in the knee may affect the patellar tendon. This is the tendon that connects the knee cap to the tibia (lower leg bone). Patellar tendonitis usually occurs because of excessive jumping and is actually called "jumpers knee." This is treated with rest, anti-inflammatory medications, and physical therapy.

Tendonitis in the ankle can occur along the outside of the ankle (peroneal tendonitis), the inside of the ankle (posterior tibial tendonitis), or at the back of the ankle (Achilles tendonitis). The tendonitis that occurs along the outside or inside of the ankle can occur because of trauma or because of mechanical instability. Another potential cause is an underlying arthritis condition. Achilles tendonitis often occurs as a result of excessive stress and repetitive trauma. The Achilles tendon is the thick cord at the back of the ankle that connects the heel bone to the calf muscle. Treatment involves rest, elevation of the heel to take the tension off the Achilles tendon, and physical therapy. Glucocorticoid injection should be avoided because of the danger of Achilles tendon rupture. Anti-inflammatory medication may be helpful.

Dr. Wei (pronounced "way") is a board-certified rheumatologist and Clinical Director of the nationally respected Arthritis and Osteoporosis Center of Maryland. He is a Clinical Assistant Professor of Medicine at the University of Maryland School of Medicine and has served as a consultant to the Arthritis Branch of the National Institutes of Health. He is a Fellow of the American College of Rheumatology and the American College of Physicians. For more information on arthritis and related conditions, go to: http://www.arthritis-treatment-and-relief.com