Tendinosis

Tendinosis, sometimes called chronic tendinitis, chronic tendinopathy, or chronic tendon injury, is damage to a tendon at a cellular level (the suffix "osis" implies a pathology of chronic degeneration without inflammation). It is thought to be caused by microtears in the connective tissue in and around the tendon, leading to an increase in tendon repair cells. This may lead to reduced tensile strength, thus increasing the chance of tendon rupture. Tendinosis is often misdiagnosed as tendinitis due to the limited understanding of tendinopathies by the medical community. Classical characteristics of "tendinosis" include degenerative changes in the collagenous matrix, hypercellularity, hypervascularity, and a lack of inflammatory cells which has challenged the original misnomer "tendinitis".

Causes

Tendinosis of the common extensor tendon of the elbow (“tennis elbow”) is a common cause of elbow pain for adults.

The general opinion is that tennis elbow tendinosis is due to tendon overuse, and failed healing of the tendon. In addition, the extensor carpi radialis brevis muscle plays a key role.