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Tendonosis: Symptoms, Causes, Treatment, and More

Tendonosis is a common condition affecting tendons, most commonly at the rotator cuff of the shoulder, which affects up to 30% of the general population.

What is Tendonosis?

Tendonosis, often referred to as chronic tendon injury, is a condition that primarily affects tendons – the tough, fibrous connective tissues that attach muscles to bones. Unlike its counterpart, tendinitis, which involves acute inflammation of the tendons, tendonosis is characterized by a degenerative process that occurs in the absence of significant inflammation. This degeneration leads to structural changes in the tendon, including alterations in collagen arrangement and cellular composition.

Tendonosis most commonly affects tendons at the shoulder (rotator cuff tendons), elbow (tennis elbow or lateral epicondylitis), knee (patellar tendon), and heel (Achilles tendon). It is prevalent among athletes and individuals engaged in repetitive activities, but it can also occur in non-athletic populations due to various factors.


The symptoms of tendonosis can vary depending on the location of the affected tendon. Common signs include:

  • Pain which is chronic and localized that often worsens during or after physical activity and can even persist at rest
  • Stiffness and reduced range of motion due to reduced elasticity in cases of tendonosis
  • Weakness leading to a decreased ability to generate force
  • Mild swelling in the affected area
  • Crepitus which creates a crackling or grating sensation when moving the affected joint


The precise causes of tendonosis remain a subject of ongoing research. Some common contributors include:

  • Overuse and repetitive Stress: engaging in repetitive activities or movements that strain the tendons beyond their capacity can lead to microtrauma and subsequent degeneration (1).
  • Age: tendonosis becomes more prevalent with age, as tendons naturally undergo changes in structure and composition over time (2).
  • Poor biomechanics: faulty movement patterns, improper technique during exercise, or poor posture can increase the risk of tendonosis.
  • Vascular changes: tendons rely on blood vessels to provide nutrients and remove waste. Changes in blood supply to tendons can impact their health and healing potential.
  • Genetics: some individuals may be genetically predisposed to developing tendonosis due to variations in collagen production and other related factors.
  • Inadequate warm-up or cool-down: failing to properly warm up before engaging in physical activity or neglecting to cool down afterward can leave tendons more vulnerable to injury and degeneration.
  • Sudden increase in activity: rapidly increasing the intensity, duration, or frequency of physical activity can overwhelm tendons that are not accustomed to such stress, increasing the risk of injury.
  • Previous injuries: tendons that have been previously injured or strained are more susceptible to further injury and degeneration. Improper healing or scar tissue formation can weaken the tendon’s structure.
  • Smoking: smoking can negatively impact blood flow, which is essential for the delivery of nutrients and oxygen to tendons. Reduced blood flow can impede the healing and maintenance of tendon tissues (3).
  • Medications: some medications, such as corticosteroids and floroquinolones, can weaken tendons and increase the risk of tendonosis (4).


Accurate diagnosis of tendonosis is crucial for appropriate treatment planning. Healthcare providers typically employ a combination of clinical assessment, imaging, and patient history to make an informed diagnosis. Some common diagnostic methods include:

  • Physical examination: a thorough evaluation of the affected area can help identify pain points, stiffness, weakness, and other clinical signs.
  • Imaging: ultrasound or MRI scans can provide detailed images of the tendon, revealing structural changes associated with tendonosis.
  • Patient history: understanding the patient’s activity level, past injuries, and symptom progression can provide valuable insights into the condition’s cause and severity.
  • Palpation: identifying the specific location of pain through techniques like palpation can aid in pinpointing the affected tendon.

Treatment Options

Managing tendonosis requires a comprehensive approach that addresses both the symptoms and underlying causes. Treatment strategies may include:

  • Rest and activity modification: initially, reducing or modifying activities that exacerbate symptoms is crucial to allow the tendon to heal.
  • Physical therapy: targeted exercises to improve flexibility, strength, and biomechanics can help rehabilitate the affected tendon.
  • Eccentric exercises: these specialized exercises involve lengthening the tendon while under load, which has shown promise in promoting tendon healing.
  • Platelet-Rich Plasma (PRP) Injections: PRP therapy involves injecting a concentrated solution of the patient’s own platelets into the affected tendon to promote healing (5).
  • Surgery: in severe cases where conservative measures fail, surgical intervention might be necessary to remove damaged tissue or repair the tendon.
  • Biological treatments: emerging treatments like stem cell therapy aim to harness the body’s regenerative potential to heal damaged tendons.


Tendonosis is a complex and often chronic condition. The causes of tendonosis are likely multifactorial and include overuse, age, poor mechanics, training errors, and genetics. Tendonosis is treated with a combination of rest, targeted exercises, and emerging research in regenerative medicine. This condition is diagnosed through a combination of patient history, physical examination, and imaging. Early diagnosis and a comprehensive approach to treatment are essential to alleviate symptoms, restore function, and prevent further degeneration.