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Tendinitis is an acute, painful inflammation of a tendon, the tough, fibrous tissue that connects muscle to bone. The irritative condition usually occurs as the result of overuse and is one of several tendinopathies. Related conditions that also may occur include tendinosis, which is a chronic degeneration of the tendon, and tenosynovitis, inflammation of the sheath that surrounds the tendon.
Tendinitis is a very common condition especially among individuals engaged in heavy labor or sports. Tendinitis can be caused by acute trauma, poor technique during activity or exercise, lack of strength and flexibility, age-related deterioration, or overload and overuse of the affected tendon. Common sites for tendinitis include the shoulder (rotator cuff tendinitis), elbow (lateral and medial epicondylitis), knee, (patellar tendinitis, iliotibial band tendinitis), Achilles tendon at the heel, and the posterior tibial tendon in the leg.
Calcific tendinitis occurs when calcium deposits form in the tendons of the rotator cuff. The cause of calcific tendinitis is unknown, but it does not appear to be due to trauma and may instead be caused by systemic disease. Calcific tendinitis often resolves spontaneously in 1 to 4 weeks (Cluett).
Chronic degeneration of the tendon (tendinosis) results from microtrauma or overuse of the tendon, with symptoms developing gradually over time. The overuse can be caused by excessive pressure or workload. While up to 4% elongation of a tendon is tolerated well, greater elongation (4% to 8%) may cause microtrauma, and elongation greater than 8% may cause macrotrauma with rupture of the tendon fibers (Rettig). Repetitive tasks and excessive exercise also may cause tendinosis. Shearing stress on the tendon may occur where tendons pass in close proximity to the bone.
Risk: Tendinitis is more common in males, and Achilles tendon tears occur 4 to 7 times more frequently in males than females (Maffulli). Middle-aged individuals are more likely to develop tendinitis (Steele) since tendons deteriorate with age. Work-related factors that increase the risk for tendinitis and tendinosis include vibration, cold temperatures, intense and sustained exertion, and maintaining awkward postures.
The use of certain broad-spectrum antibiotics, known as fluoroquinolones, is associated with increased risk of tendinitis. Individuals who use steroids or have decreased kidney function (renal insufficiency) are at higher risk of developing fluoroquinolone-associated tendinitis. Fluoroquinolone-associated tendinitis often occurs bilaterally in the Achilles tendons and also has been reported in the shoulders and hands, whereas overuse tendinitis usually occurs on one side only.
Calcific tendinitis usually occurs in individuals between the ages of 30 to 40, and is more common in diabetics (Cluett). Incidence and Prevalence: Incidence of tendinitis as an occupational injury is 1.1 per 100,000 individuals who work full-time ("Incidence Rates").
Overuse tendinitis is most common in the wrist and hand, and comprises between 25% and 50% of all sports injuries (Rettig). |