Tendon pain at the elbow, heel, knee, or other tendon was always called tendonitis. Small tears of the tendon would set up an inflammatory response. When the injury doesn't heal before it's injured again, chronic pain can occur. We now know that in chronic cases, there isn't active inflammation. There's a process called tendinosis.

In tendinosis failed healing, not inflammation is the problem. The cells are disorganized. Some of the tissue cells are growing larger called hypertrophy. There's a loss of blood supply to the bundles of tendon cells. There may even be a lack of nutrition to the repair and remodeling cells.

You may also hear the term tendinopathy. This just means tendon injury without describing exactly what's wrong. Tendonitis and tendinosis are two types of tendinosis.