The Difference Between Tendonitis and Tendinosis (and how this affects your treatment plan)

Here’s a common question we here in the clinic: “Do I have tendonitis or tendinosis?  And what does that mean?”

Since these 2 terms are used so frequently, and often interchangeably, I wanted to clear up what they both mean.

In addition, once we cover what they both mean, then we can discuss how understanding the difference can improve your success when designing a treatment plan.

(If you’d like to skip reading this post, I summarize everything in the video at the bottom of the page.)

So let’s start with tendonitis…

If you break the word down, it means inflammation of a muscle tendon (“-itis” stands for inflammation).

This means that the muscle is irritated where it tapers down into a tendon and attaches to the bone.

The 2 examples I use in the video and that I’ll use in this post are “rotator cuff tendonitis” and “Achilles tendonitis.”

So let’s say you decided to do a bunch of overhead activity this weekend, like chopping some wood, painting your ceiling or throwing the football around.

And come Monday morning, your shoulder is really sore.  In this case, it’s very likely that you have rotator cuff tendonitis, meaning that your rotator cuff muscles/tendons are inflamed.

You can imagine a similar scenario with your Achilles tendon after a long hike and a lot of walking.

Here are the basic characteristics of your issue (tendonitis):

• The tendon is inflamed and irritated
• Swelling and warmth are common, as your body is increasing blood flow to the tendon to help repair and heal it
• At this point, if you don’t have any previous injuries, there shouldn’t be any structural damage

So as you can see, this is an “acute” or short-term issue that will hopefully resolve with things like rest and ice (although you probably know by know that rest and ice don’t always work…).

Now let’s look at someone with a longer-term, more chronic issue, which will lead to tendinosis…

Picture someone who has had multiple shoulder injuries over the years and who’s been having a low-moderate level of shoulder pain over the last 1-2 years.

Their pain is pretty much constant now and doesn’t vary much, and on a recent MRI they were found to have “moderate tendinosis” of the rotator cuff tendons.

So how do the 2 differ?

Here are the characteristics of the second person with “tendinosis”: