People often confuse the terms tendonitis, tendinosis, and tendinopathy. These terms, along with paratenonitis, tendon rupture, and partial tendon rupture, describe a variety of tendon conditions, including inflammation, degeneration, and injury.

Tendons are the fibrous tissues that connect muscle to bone, and there are hundreds of tendons throughout the body. Certain tendons are more prone to problems than others. For example, many people have strained an Achilles tendon at one point or another. Moreover, a single tendon can have more than one problem at a time. For example, a person who has tendonitis can also have tendinosis.

Below are descriptions of the terms used to describe common tendon conditions.

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Tendonitis

Once used to describe almost any tendon pain, medical professionals now only use the term tendonitis to describe inflammation of the tendon (the suffix “itis” indicates inflammation). Patients may experience localized pain, swelling, warmth, and redness. Recommended treatments to reduce inflammation may include resting the affected joint and taking over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (e.g. Motrin, Advil), or naproxen (e.g. Aleve, Naprosyn). Patients with tendonitis typically recover within several weeks. Tendonitis is less common than tendinosis. Chronic tendonitis can lead to tendinosis.

Read about Achilles Tendonitis and Tendon Injuries

Tendinosis

Experts make a distinction between tendonitis and tendinosis, which is the non-inflammatory degeneration of a tendon. This degeneration can include changes to the structure or composition of the tendon. These changes often result from repetitive micro-traumas or failure of the tissue to heal following a tendon rupture.

Key differences between tendonitis and tendinosis:

  • Unlike tendonitis, which can often be successfully treated within several weeks, tendinosis can take several months to treat.
  • Treatment methods for tendinosis and tendonitis may vary. For example, some experts assert that tendinosis should not be treated with NSAIDs, because NSAIDs inhibit the growth of collagen, which is necessary for tendon healing.1

Some practitioners use the term tendinosis and tendinopathy (defined below) interchangeably.

Paratenonitis

Certain tendons in the body, like the Achilles tendon, have a surrounding thin sheath of tissue, called the paratenon. When this tissue becomes inflamed it is called paratenonitis. This condition cannot be definitively diagnosed without a biopsy and is therefore not commonly diagnosed. Moreover, some practitioners do not believe paratenonitis is a separate diagnosis at all. Since the treatment for paratenonitis and tendonitis both involve reducing inflammation, it may not be essential to make this distinction for treatment purposes.2

Complete and partial tendon ruptures

When the tendon tears it is called a rupture. If a tendon is torn in two pieces it is called a complete rupture, and if some of the tendon still remains intact it is called a partial rupture.

Some physicians make a distinction between acute and chronic tendon ruptures.

  • An acute tendon rupture is a one-time event that can result in immediate pain and decreased function of the affected joint, and may be followed by swelling or bruising. An acute rupture is typically recognized and treated within a week of injury.
  • Chronic tendon ruptures may result from:
    • A partial rupture that slowly worsens over a prolonged period or
    • An acute rupture that goes untreated for several weeks (many experts believe this time varies between 4 to 6 weeks, depending on the tendon).3

Depending on the patient, the affected joint, the severity of the tear, and the duration of symptoms, a doctor may recommend either surgery or a period of rest to treat the tendon rupture.

Tendinopathy

The suffix “pathy” is derived from Greek and indicates a disease or disorder. Therefore, tendinopathy literally means a disease or disorder of a tendon. Tendinopathy (sometimes spelled tendonopathy) is typically used to describe any problem involving a tendon.

While most experts define tendinopathy as an umbrella term to describe all tendon conditions, others may use it to describe a chronic tendon condition that fails to heal. For example, a runner who has suffered a hamstring tendon rupture that does not heal properly may be diagnosed with tendinopathy.

See Chronic High (Proximal) Hamstring Tendinopathy

To avoid confusion, patients who are diagnosed with tendinopathy should ask their doctors how they define the term.

References:

  1. Tsai WC, Tang FT, Hsu CC, et al. Ibuprofen inhibition of tendon cell proliferation and upregulation of the cyclin kinase inhibitor. J Orthopedic Resear. 2004. 22(3): 586–591. doi: 10.1016/j.orthres.2003.10.014.
  2. Paavola M, Järvinen TA. Foot Ankle Clin. 2005 Jun;10 (2):279-92. Review. http://www.ncbi.nlm.nih.gov/pubmed/15922919. Accessed October 7, 2014.
  3. Flint JH, Wade AM, Giuliani J, Rue JP. Defining the terms acute and chronic in orthopaedic sports injuries: a systematic review. Am J Sports Med. 2014 Jan;42(1):235-41. doi: 10.1177/0363546513490656. Epub 2013 Jun 7. Review. PubMed PMID: 23749341.