Tendinitis is a problem that causes inflammation and is most often the result of an acute injury. This problem is characterized by swelling, redness, warmth, and pain. When the tendon is seen under the microscope, inflammatory conditions have specific cells that the body brings to that area of the body to help control the inflammation and heal the injured tendon.
Tendinosis usually causes no redness or warmth of the surrounding soft tissues, although the area can be painful to touch. Tendinosis is a chronic problem, meaning it develops gradually and lasts a long time. When seen under a microscope, inflammatory cells are not present, although chronic damage and microscopic tears of the tendon may be seen.