Overview of Tendonitis
Tendonitis (or tendinitis) is inflammation of a tendon, which is tissue that attaches muscles to bones. Tendonitis, which often results from repetitive action that puts extra pressure on the tendon, usually causes pain in a joint area, such as the wrists, elbows, knees, hips, heels, and shoulders.
Types of Tendonitis
Tendonitis can be classified by the area of the body it affects. In some cases, it is named for an activity that frequently causes pain (e.g., tennis elbow), but causes for the condition are not limited to that activity. Types include the following:
- Achilles tendonitis (occurs in the Achilles tendon or "heel cord" in the foot, affecting jumping, walking, jogging, and standing on the toes)
- Adductor tendonitis (affects the inner thigh, hip, and groin area; common in athletes)
- Biceps tendonitis (involves the tendons that connect biceps muscles to the shoulder; often occurs when the arms are repeatedly lifted above the head)
- Golfer's elbow (affects the inside of the elbow, forearm, and wrist)
- Patellar tendonitis (also called jumper's knee; affects the tendon that connects the kneecap to the shinbone and is common in athletes who play basketball, volleyball, and soccer)
- Posterior tibial tendon dysfunction (PTTD or adult-acquired flatfoot; occurs in the foot when the tendon cannot support the arch)
- Rotator cuff tendonitis (affects the rotator cuff, which are tendons that attach four muscles that help the shoulder joint move)
- Tennis elbow (affects the outside of the elbow and sometimes, the outside of the forearm and wrist)
- Trigger finger (results from irritation of the covering surrounding a tendon [sheath] in a finger; may cause the finger to remain bent or straighten without warning)
- Wrist tendonitis (e.g., de Quervain's tenosynovitis; results from irritation of the sheaths of the tendons on the thumb side of the wrist, causing moving the wrist and grasping things to become very painful)
Incidence and Prevalence of Tendonitis
Tendonitis is a fairly common condition. Overall incidence and prevalence increases with age. Some types are more common in men (e.g., golfer's elbow) and some are more common in women (e.g., trigger finger). Trigger finger occurs more often in patients who have diabetes.
Tendonitis Risk Factors and Causes
Tendonitis can occur when a particular tendon is overused, for example, through repeated actions (e.g., swinging a tennis racket, gripping a hammer). Stress on the tendon causes small tears, which the body tries to repair on its own. Continued activity slows down this process, resulting in more tearing and more pain.
Repetitive motion that puts unnecessary stress on a tendon and increases tearing results in an increased risk for tendonitis. Muscle imbalance (e.g., in weight lifters) also increases the risk.
Aging can increase the risk for tendonitis, as tendons become less flexible. Injuries (e.g., sports-related, work-related) are another common cause, as are diseases such as rheumatoid arthritis, hypothyroidism, diabetes, and tuberculosis.
Athletes are at increased risk for developing tendonitis because of repeated actions. Golfers grip their clubs; basketball players jump to make their shots; pitchers throw baseballs. Just about any sport can increase the risk for tendonitis, as can hobbies (e.g., knitting, gardening, playing a musical instrument) and other activities (e.g., carpentry, yard work, painting).