Are there 3 main types of SI joint dysfunction?

I have been thinking a lot recently about different ways to classify different types of SI joint dysfunctions.  Based on all the reading I’ve done, learning from other people who’ve struggled with this issue, and talking with various medical professionals, I’m starting to think there are 3 main types.

The following types refer both to the nature of the problem, as well as the symptoms, if that makes sense.  All of them involve some sort of weakening of or injury to the ligaments that are supposed to hold the joint in place.

Let me see if I can explain…

Type 1. Joint Hypermobility due to a Ligament Injury 

Joint hypermobility means that a joint is moving more than it should, in this case because the ligaments are stretched out.

My friend Kelsey struggled with SI joint dysfunction for a few months, at one point in time, however her case was pretty easily resolved compared to mine.

She had stretched out the ligaments in her right SI joint because she was in a car accident where she was rear-ended, while she was stomping her foot down on the break.  That impact created too much force for her SI joint ligaments, so it created a lot of pain.

However, Kelsey was able to recover with one course of physical therapy, with the first physical therapist she happened to see.  (God, could we all be that lucky!).

Her pain was caused by her right SI joint moving beyond its normal range of motion.   Any time you have a joint that’s moving too much, it puts strain on all of the ligaments of the joint (not just the one that may have been initially injured).  It also overworks the muscles, which can spasm up to protect the area, and create inflammation.

This, obviously, can be painful.

However, Kelsey never seemed to experience the main symptom that has plagued me, which is my joints moving out of place and staying that way.

Type 2.  Hypermobility can lead to hypomobility: Joints that get stuck in an abnormal position

Here’s the thing about hypermobile SI joints.  In some people (like me), the hip bones can rotate out of place, in relation to the base of the spine, and then stay that way.

With my SI joint dysfunction, my main symptom was actually never pain.  It was that one of my SI joints would get “stuck,” and I wouldn’t be able to fully use the leg on that side.  Then that would create pain, but it seemed to be more as a result of having my leg restricted.  If I didn’t move, it usually didn’t hurt.

So in technical terms, you have a joint that was hypermobile (moving too much), but once one of the hip bones moves enough that it gets jammed against the base of the spine and doesn’t move anymore, then it has become hypomobile.

From my conversation with the first physiatrist I ever saw, I have come to understand that whether or not someone’s SI joints get stuck actually has a lot to do with the shape of the bones they were born with.

In my physical therapy prerequisite classes, I have learned that there are multiple factors that can affect how stable a joint is, based on its shape.  Some people are simply born with more stable joint shapes than others.

Personally, I had the luck to be born with joints that are on the extremely unstable end of the spectrum.  (The orthopedist who performed my surgery for compartment syndrome has actually pointed this out about most of the joints in my body).  Basically, I’m prone to injury more than other people, because my joint shapes leave me vulnerable.

So basically, it seems that the main difference between someone like Kelsey and me might have less to do with the way we were initially injured, or the types of things we did to recover, but the actual shape of our bones, which obviously neither of us can control.

So if you’re suffering from prolonged SI joint dysfunction, and you don’t understand why you aren’t getting better compared to other people, it’s not your fault.  You may be doing everything right.  But you can’t help the shape of your bones. 

(What you can do, according to my orthopedist and everyone else, is to do everything you can to strengthen your muscles, because that helps to protect the joints).  

Type 3.  Joint Hypermobility caused by a disease or genetic condition

This is the category of SI joint dysfunction that I am the least familiar with.  However, there are conditions known as connective tissue disorders, in which someone is genetically predisposed to have a weakening of their ligaments and other connective tissues.

For example, one of the first places in the body that Ehlers-Danlos syndrome seems to affect is the SI joints.

If your doctor suspects you may have a condition like this, it’s obviously a very important matter to investigate.  However, I don’t want anyone to worry unnecessarily that they have it.  It is something to talk to your doctor about, and then they will be able to do certain tests (blood work and possibly x-rays, I believe) to see if you have it or not.

If you want to learn more about connective tissue disorders, I really recommend the blog Jelly-Like Joints, written by a highly knowledgeable patient.

So, these are my main three.  

What do you think?  Do you agree, or have any suggestions?  Feel free to chime in below!  This is really just a hypothesis I’m working on, so I want to know if I forgot anything.

Thanks for reading!

Here are a few related posts I’ve written previously:





3 thoughts on “Are there 3 main types of SI joint dysfunction?

  1. The Bookish Crafter says:

    I’m honored that you linked to my blog! 😀 It’s nice to have an organized list of all the causes of joint hypermobility. I never thought of becoming hypermobile from an injury, but I knew people who probably were hypermobile from their bone structure when I was taking ballet lessons. I wonder what effect sports that encourage flexibility have on joints in the long-term. Do people get hypermobile joints simply from all the stretching in ballet, even if their bone structure doesn’t make them hypermobile? Or is it really just that they are flexible, but they don’t have joint hypermobility?

    • sunlight in winter says:

      Of course! I love your blog!

      Hmm… I’ve thought a lot about your question! I don’t know much about ballet, but I found this article on how SI joint injuries can actually be a pretty common result of yoga poses that stretch out the ligaments:

      I think the takeaway from this is that any activity that stretches out the ligaments and creates extra mobility in the joint is likely to result in pain and injury. Our ligaments are supposed to be a certain length, and any “wiggle room” beyond that, so to speak, does not help us. So, if someone is able to keep up with the rigorous demands of ballet dance, I would guess that the main factor is that they have more muscle flexibility than the average person, and possibly some hypermobility due to bone shape (which doesn’t necessarily lead to injury right away, just makes you prone to injury).

      Hope that makes sense!

      • The Bookish Crafter says:

        Yes, that makes sense! When I was taking ballet lessons in middle school there was a lot of emphasis on strengthening so we could handle the flexibility, and on being careful not to overstretch. For the first three years, we did strengthening exercises on the floor at the beginning of every class.

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