Tendonitis or Tendinosis?

Distinguishing the signs and symptoms of joint pain – and why it’s a critical difference.

Vol. 26 • Issue 6 • Page 8

Sports Medicine Focus

Tendinosis, the degenerative condition in a tendon, is far more severe and much less diagnosed than its cousin tendinitis, an inflammatory condition. Although tendinosis diagnoses are less common, the condition is actually more prevalent, especially among athletes. The more alarming fact is that popular treatments for tendonitis can actually have little-to-no success when treating tendinosis, which could delay or even terminate an athlete’s career.

Patellar tendinosis is often referred to as “jumper’s knee” or “runner’s knee.” It occurs mostly with athletes whose knees, specifically the tendon, are making rapid movements in multiple directions and being overused, like those in sports such as volleyball and basketball, or with strenuous activities like running and hiking.

Differentiating Tendinopathies

“The majority of athletes I see with patellar tendinopathies usually fall into two categories: high school basketball players, and runners of any age coming in at a close second,” said Cody Barnett, PT, owner and physical therapist at Bodyworx Physical Therapy in Wichita, Kan.

This injury is most certainly not limited to athletes of sports that mainly require movements like jumping. “It’s like tennis elbow; really, only about 10 percent of people who have tennis elbow actually play tennis,” Barnett said. However, patellar tendinosis specifically is found quite often in the athletic population, especially among basketball and volleyball athletes.1

So, why is tendinosis in general more common yet less diagnosed than tendonitis? For starters, it’s not always noted as being a different condition than tendonitis. “People in general have a tendency to let things go,” said Barnett. “The medical community in general, even the physical therapy population, is not as well educated on the differences as they should be.”

“The knowledge is improving, but I wouldn’t consider it good,” said Barton Bishop, PT, DPT, SCS, CSCS, chief clinical officer of Sport and Spine Rehab in Rockville, Md., and chair of the Knee Special Interest Group of the APTA’s Sports Physical Therapy Section. “There’s still going to be a lot of PTs out there that see patients who are coming in with anterior knee pain, and get a diagnosis from a medical doctor or their family physician that says ‘patellar tendonitis’ and they treat it as such. They treat it with ice massage, rest, and other tendonitis treatments.”

Bishop says it’s crucial for PTs to delve into the causes behind the symptoms of their condition, rather than just going off what they think the patient has. “They don’t think, ‘why do these people have the condition?'” he said.

Therapists should be using a sort of process of elimination when it comes to figuring out whether their patient has degeneration or inflammation, advised Bishop. Since the patellar tendon is so close to the skin, PTs should be looking for obvious, visible symptoms of tendonitis to rule out tendinosis.

“What you should see with tendonitis patients are the hallmark signs of inflammation, like swelling, redness, or palpable amounts of fluid in or around the tendon,” said Bishop. And if you don’t see these signs, the pain the patient is experiencing is most likely caused by the degenerative condition rather than the inflammatory. “In the absence of those symptoms, the likelihood is that people don’t have tendonitis — but they have tendinosis, and this condition must be managed in a different way.”

Role of Eccentric Training

Treatments for tendonitis are vastly different from those of tendinosis, and there is no room for overlap. In fact, tendonitis treatments can worsen the condition of a patient who actually has tendinosis.

“It could worsen the condition if you’re talking using anti-inflammatories, icing and resting with no physical activity,” said Bishop. “The most important thing is to understand the mechanism of tendonitis and tendinosis, and the pathomechanics happening in the tendon. Rest and modification of activity and increasing inflammation is the opposite of what you want to do in a tendinosis condition.”

So what are the right ways to be treating this condition? Eccentric training has been studied and shown to be a positive and effective treatment for tendinosis patients for multiple parts of the body.2Bishop says research is clear that eccentric activity and eccentric training are going to be the best way to treat tendinosis. “It’s been shown not only in the knee, but also the hamstring, Achilles, elbow, shoulder — all over the body.”

In fact, eccentric loading and training should be the preferred, primary treatment for any PT to utilize before considering an alternative like surgery, which comes with its own risks and recovery time. In a 2006 study published by The Journal of Bone and Joint Surgery, authors performed a randomized controlled trial in which one group with patellar tendinosis received a 12-week eccentric training program, while the other group with the same condition went in for an open tenotomy, followed by an exercise regimen slowly leading to eccentric training.2

The authors concluded that there was no particular advantage to open tenotomy surgery over an eccentric training intervention period. They recommend any tendinosis patient receive a 12-week rehabilitation program with eccentric training before considering surgical operations.2

Complementary Therapies

As important as eccentric training is for tendinosis conditions, there is always something more PTs can be doing. “There is no one treatment that is going to fix everything. PTs should always be thinking ‘eccentric training and,'” said Bishop.

Other treatments that can assist in the healing process during eccentric training have become more prevalent in the physical therapy field. Low-level laser therapy (LLLT) has been known to have a positive effect on tendinopathies when working alongside eccentric training. “Laser has become more and more popular. It has potential, and there are some nice randomized control trials that are showing that laser treatment is effective,” said Bishop.

In a 2014 study, 21 patients suffering from patellar tendinopathy were divided into three groups: one treated with eccentric training alone, another treated with LLLT alone, and the third treated with both. Each group was treated for a 4-week intervention period.3

The authors came to find that the combination of eccentric training and LLLT treatments was more effective than either treatment alone, and recommended that PTs consider LLLT as a useful additive to their patients’ eccentric training. The study was published in the International Journal of Photoenergy.3

“There have also been articles out on platelet-rich plasma (PRP) injections,” said Barnett. “It’s definitely showing some promise.” In a 2012 study, 36 patients were treated with PRP injections after already starting eccentric training. The results concluded that PRP should also be considered as a treatment combined with eccentric training before opting for surgery.4 Barnett does caution that he would still recommend conservative physical therapy first before trying an invasive treatment such as PRP injections.

The most interesting take from this study is that group one, who were treated with either cortisone, ethoxysclerol, or surgical treatment, or a combination of these, did not have strong results as compared to group two, who had no history of previous failed treatments.4 This brings back the original point: it is crucial to distinguish between tendinosis and tendonitis so that patients can receive the proper treatment based on the correct diagnosis.

“There’s no question that if we are not fully versed in the difference in conditions and treatments, we could be setting up our patients for long-term disability and re-injury,” said Bishop. “We would be harming our athletes’ potential to continue to participate in the sport that they love.”


  1. http://bmb.oxfordjournals.org/content/110/1/47.abstract
  2. http://bjsm.bmj.com/content/48/7/638.1.abstract
  3. http://jbjs.org/content/88/8/1689.abstract
  4. http://www.hindawi.com/journals/ijp/2014/785386/
  5. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3427446/

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