Tendons are strings of fibrous tissue that connect muscles to bones. It is this connection that allows joint movement. When muscles contract, they pull on tendons that make bones move. In order for the tendons to glide, they move within 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 in which the sheath through which a tendon slides becomes inflamed. This leads to severe pain. The pain is often made worse by use of the affected joint. However, when tendinitis becomes severe, there may be pain at rest.
Since muscles and tendons surround most joints, tendonitis is quite common. The diagnosis of tendinitis is relatively simple for the experienced physician. In general, the diagnosis is made by history and physical examination. In cases of difficult diagnosis, magnetic resonance imaging is useful to confirm the diagnosis.
Some of the most common types of tendinitis are:
Shoulder tendonitis. The most commonly affected shoulder tendons are the rotator cuff and the biceps tendon. The rotator cuff consists of four tendons that sit on the bone of the upper arm. The location of these tendons and the muscles they attach to are what give the shoulder such a wide range of motion. Rotator cuff tendinitis can occur as a result of repetitive activity or degeneration of the tendon. The pain is felt with most movements and is located on the outside of the shoulder. The biceps tendon allows the arm to flex 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 successfully treated with anti-inflammatory medications, physical therapy, and sometimes glucocorticoid injections.
Elbow tendonitis is usually localized well on the outside and is called lateral epicondylitis or tennis elbow. It can also occur along the inside of the elbow medial epicondylitis. This is called golfer’s elbow. Treatment consists of physical therapy, stretching and strengthening exercises, splints, and injections. In rare cases, surgery is required.
Wrist tendonitis arises due to repetitive motion. A special type of tendonitis, called Dequervain’s tendinitis, is felt on the outside of the thumb. Tendonitis in these areas is treated with glucocorticoid injections and immobilization with a splint. Other physical therapy modalities may be helpful. Sometimes surgery is required. Tendonitis in the fingers can cause fingers to become trapped. This is called “trigger finger.” Trigger finger usually responds to injection but may require surgical intervention.
Knee tendinitis can affect the patellar tendon. This is the tendon that connects the kneecap to the tibia (lower leg bone). Patellar tendonitis usually occurs due to excessive jumping and is actually called “jumper’s knee.” This is treated with rest, anti-inflammatory medications, and physical therapy.
Ankle tendinitis can occur on the outside of the ankle (fibular tendonitis), on the inside of the ankle (posterior tibial tendonitis), or on the back of the ankle (Achilles tendonitis). Tendonitis that occurs along the outside or inside of the ankle can occur due to trauma or mechanical instability. Another potential cause is an underlying arthritic 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 consists of rest, heel elevation to relieve stress on the Achilles tendon, and physical therapy. Glucocorticoid injection should be avoided because of the danger of Achilles tendon rupture. Anti-inflammatory drugs may be helpful.
A new treatment approach has made the need for surgery less likely for patients with chronic tendonitis. The procedure is called a “percutaneous needle tenotomy.” In this procedure, a small-gauge needle is inserted using ultrasound guidance. The needle is used to irritate the tendons by stimulating the inflammatory response. Next, platelet-rich plasma, obtained from the entire patient, is injected into the area where the tendons have been irritated. Platelets are cells in the blood that contain multiple growth and healing factors. The end result is the formation of new healthy tendon tissue.