Tendinosus vs. Tendinitis

I had a patient come to me the other day that had been dealing with achilles “tendonitis” for the last 2 years. 2 years he had this achilles pain!!! He had been to 2 other PT clinics with some minimal improvement, but had never been able to return to his recreational activities (hiking, tennis, etc.), without his achilles flaring up. He finally went back to his podiatrist, who subsequently referred him to our facility. He said that most treatment focused on modalities with some degree of LE loading, but usually involving the whole leg without any isolated ankle activities.

Unfortunately I had to be the bearer of bad news and tell him that the modalities and ROM may have made him feel better, but they would never address what was really going on in his achilles. For after hearing his subjective Hx, and after completing my objective examination, I told him that what he had been dealing with was not “tendonitis,” but tendinosus.

It’s disappointing to me to see that even today medical professionals are still having difficulty distinguishing between achilles tendonitis and tendinosus. In the early 1990’s, it was discovered by sports medicine professionals that most people that have achilles pain have achilles tendinosus. Accoding to Wilson et. al, American Family Physician, there are such things as acute tendinopathies, but most patients that have chronic symptoms suggest they have a degenerative condition that would be better characterized as a tendinosus or tendinopathy.

In radiologic tests (such as an MRI), the difference between a tendinosus is: a) the absence of any inflammation and b) a change in the appearance of the collagen of the tendon. Histologic studies done on painful achilles tendons have demonstrated a more disordered collagen arrangement together with increased proteoglycan ground substance and neovascularization. In layman’s terms, the muscle tissue is scarred and thickened, and that must be corrected to allow for the muscle to heal properly and function correctly. Otherwise loading will result in more “tearing” or further damage to the scarred collagen, leading to increased pain.

Treatment options for this patient should have started with cross-friction massage, which he did not receive at all from either of the previous PT clinics. This would have allowed for the scarred collagen to be broken down. To assist with the proper collagen repair, exercises focusing on stimulating the achilles tendon should have followed, progressing from low load isometrics to eccentric muscle activity. Something he also did not receive at the previous facility. It is important that clinicians realize the difference between the two different tendon diagnoses. For the diagnosis will help to determine the appropriate treatment plan. And the appropriate treatment plan, can help to prevent a prolonged course of rehabilitation and allow for optimal outcomes and a quicker return to full function.

For more information on achilles tendon injuries or tendinosus check out these sites: