Tendonitis is an aseptic inflammatory reaction of the tendons or tissues surrounding the tendons caused by excessive activity or other causes. The main manifestations are pain, tenderness, motor dysfunction and inflammatory response at the site of the lesion. It is often combined with small lacerations of the tendon caused by overexertion and is commonly referred to as tendon injury or tendinopathy. It mostly occurs in the shoulder, elbow, knee and ankle joints.