What is Tendinitis vs Tendinosis ?
What comes to mind when you think of tendinitis? If you’re like most people, you’ll start to think about burning discomfort, reduced range of motion and pain. In particular, pain with repetitive activities, including the sports and hobbies you enjoy. However, the reality is that our understanding of tendon injuries have evolved over the years. We now know that most of the symptoms we typically associate with tendinitis are actually often due to a different type of tendon pathology, termed tendinosis. Understanding the difference between these two terms can have important implications in the recognition and management of these painful conditions.
Tendons are tough, dense connective tissues that join muscles (musculotendinous junction) to bones (enthesis). They primarily function to create movement of a body part by transmission of muscle contraction forces to the skeleton.
The term tendinitis refers to an injury to the tendon that creates an inflammatory response. This can be due to micro-tears that occur when the musculotendinous unit is suddenly overloaded with significant tensile force or it may come about after degeneration occurs in the tendon. Tendinitis is ultimately caused by inflammation and will lack findings of microscopic tendon damage.
On the other hand, tendinosis is a degenerative condition that occurs when tiny tears occur in the tissue in and around the tendon. Tendinosis can develop due to overuse or repetitive activity or may begin with an acute injury. In an attempt to heal these micro-tears in the tendon, the body orchestrates a repair process that includes laying down new collagen fibers along with cells, nerves and blood vessels. Unfortunately, this process results in a disorganized matrix of immature type III collagen fibers (compared to mature type I fibers seen in healthy tendon tissue), nerves and vascular structures that do not provide the same utility as blood vessels. This partial repair of the damaged tissue results in an abnormal scar tissue which can be a source of pain and ultimately causes the tendon itself to become weaker and is termed tendinopathy. In particular, chronic overuse tendinopathy can impair the function of the tendon to such an extent that it can tear or possibly rupture with further injury.
Who is at risk for developing Tendinopathy?
This is a common condition and occurs most frequently in adults between the ages of 30-60 years old. Oftentimes, tendon injuries occur near joints, such as the elbow (lateral epicondylitis – “Tennis Elbow”), shoulder (rotator cuff injuries), hip (gluteal tendons on outside of hip), knee (patellar tendinitis – “ Jumper’s knee”) and ankle (achilles tendinitis) . Certain systemic diseases that affect the whole body, such as rheumatoid arthritis and diabetes, may also result in tendinopathy.
What are the common symptoms of Tendinopathy?
- Localized pain, swelling and tenderness over a tendon.
- Pain worse at night
- Pain aggravated by movement or certain activities (particularly repetitive activities)
- Stiffness in the affected area in the morning
How is Tendinopathy managed?
The first step in the management of this condition is to have the painful region evaluated by a medical provider. Most often, a clinical diagnosis is made on the basis of the patient’s history, physical exam and possible imaging of the affected area. Certain imaging studies such as MRI and ultrasound can help to differentiate between tendinitis and tendinosis/tendinopathy.
In cases where tendinitis is suspected, the timeline for recovery is approximately 4-6 weeks. Initial treatment will consist of activity modification including avoiding the repetitive or overuse motions that are linked to the pain and allowing the affected body part to rest. As this is an inflammatory condition, short term use of anti-inflammatory medications (i.e. ibuprofen) can be helpful. Braces and straps may also be recommended depending on the location of the pain, such as a Cho-Pat elbow strap that can be used for tennis elbow. Additional treatment options include the use of ice, compression, taping and massage. Physical therapy can be used to help stretch the tendon, strengthen the surrounding musculature and enable gradual loading of the affected tendon. In certain cases, a steroid injection may be indicated to help decrease inflammation and relieve pain, however it is important to note that steroids may impair tissue healing.
If patients do not respond to the above conservative treatments and if tendinosis is suspected, additional treatments may be considered. These include regenerative medicine treatments such as platelet-rich plasma (PRP) that is derived from the patient’s blood. PRP is known to have growth factors and may be injected into the affected region to help stimulate healing of the injured tendon. In certain cases, this may be done in combination with a medical procedure known as tendon fenestration to help promote further healing. Surgery may be indicated in cases of severe tendinopathy that have not responded to any of the above treatments.
Fu SC, Rolf C, Cheuk YC, Lui PP, Chan KM. Deciphering the pathogenesis of tendinopathy: a three-stages process. Sports Med Arthrosc Rehabil Ther Technol. 2010;2:30. Published 2010 Dec 13. doi:10.1186/1758-2555-2-30.
Steinmann S, Pfeifer CG, Brochhausen C, Docheva D. Spectrum of Tendon Pathologies: Triggers, Trails and End-State. Int J Mol Sci. 2020;21(3):844. Published 2020 Jan 28. doi:10.3390/ijms21030844
Submitted by Ron Avraham, MD.
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