The tendons are thick, fibrous tissues that attach your muscles to your joints. Tendonosis (or tendinosis) is a chronic condition involving the deterioration of collagen (a structural protein) in the tendons.

Tendonosis is caused by chronic overuse of a tendon. It can occur in any tendon but most often occurs in the tendons of the:

  • heel (in the Achilles tendon)
  • wrists
  • elbows
  • knees (in the patellar tendon)
  • shoulder (in the rotator cuff)

Tendonosis is different and more serious than tendonitis. Tendonitis is acute (short-term) inflammation in the tendons. It may go away in just a few days with rest and physical therapy. Tendonitis results from micro-tears in the tendon when it’s overloaded by sudden or heavy force.

There is no inflammation in tendonosis, but rather the actual tissue in the tendons is degrading. Untreated tendonitis can eventually lead to tendonosis. It’s important see a doctor for a proper diagnosis. Tendonosis and tendonitis are treated differently.

Symptoms of tendonosis include:

  • pain in the affected tendons when moved or touched
  • stiffness and restricted movement in the affected area
  • in some cases, the appearance of a tender lump

Tendonosis is caused by chronic overuse of a tendon. Tendons require a long time to heal because of their poor blood supply. Continued and repetitive activity puts stress on the tendon and slows down the healing process. This eventually leads to tendonosis.

Tendonosis is more common in people who are middle-aged or older since the tendons are more prone to injury. It can also occur in people:

  • who exercise vigorously or play sports without enough rest in between
  • who perform repetitive work tasks (like driving machinery)
  • whose tendonitis is left untreated
  • with poor posture
  • who wear poor-fitting or improper footwear
  • with tight calf muscles

A doctor will first take a detailed history and perform a physical examination. Be sure to tell your doctor exactly where you’re experiencing pain, when the pain started, and which activities make it worse. The doctor might touch (palpate) the area where you’re experiencing pain directly to pinpoint where the pain and swelling are most severe.

Your doctor might also take an X-ray, MRI, or ultrasound to evaluate how much of the tendon is affected, to look for any tears, or to rule out other causes.

The main goals for treating tendonosis include preventing injuries, reducing pain, thickening the tendon, and replenishing collagen within the tendon.

Treatment recommendations include:

  • resting the affected tendon
  • taking a break every 15 minutes if your work involves performing a repetitive task
  • applying ice for 15 to 20 minutes, several times a day
  • using ergonomic keyboards and chairs
  • wearing braces or tape for support of the affected tendon
  • performing light stretching exercises
  • moving the affected area through its natural range of motion to prevent shortening of the related muscles and increase circulation
  • physical therapy
  • light eccentric strength training
  • massage
  • nutrition, including vitamin C, manganese, and zinc for the synthesis of collagen production

A nutritionist can help you see if your intake of nutrients needed for collagen production is sufficient.

Unlike with tendonitis, anti-inflammatory drugs and cortisone injections aren’t recommended for treating tendonosis. These types of medications may inhibit the repair of collagen.

Tendonosis can make your tendon more prone to injuries. The tendon may rupture (tear) and require surgery.

Tendonosis takes longer to heal than tendonitis. If recognized early, it might be treated successfully in as little as six weeks. Chronic cases often take three to six months to heal completely, and sometimes longer. About 80 percent of people are able to recover fully.

Massage, stretching, strength training, and warming up before starting work or exercise can help to prevent tendon injuries and keep the tissue as healthy as possible.

Getting prompt treatment for acute tendonitis and allowing your tendons to rest and recover when experiencing pain or after intense exercise can also help prevent tendonosis from developing.

Wearing supportive, cushioned athletic shoes can also help prevent tendonosis.