I can attribute two definite factors to how I developed my SI joint injury, and a possible third.
Definite Factor #1: Abnormal Movement Patterns Over Time
It all started in the fall of 2011. I had actually been having very significant knee pain due to chondromalacia patella, a condition involving inflammation in the knee.
For a few months, I was not able to put weight fully on my right leg (the affected side). I walked with a limp, always leading with my left leg.
Over time, the muscles in left leg, particularly in the front of my left hip, became very tired and tight from being constantly asked to take on more work than they were accustomed to.
At the same time, I think the rest of the muscles in my body suffered as result of the inactivity. I tried to perform non-weight-bearing exercises as much as I could, but whatever I was doing was obviously not enough because I ended up pretty weak and out of shape.
Definite Factor #2: Blunt Force/Trauma to the Area
The final blow came one day when I was at the hospital for an x-ray of my knee. I had to walk all the way in from the parking garage to the main entrance, and my knee was screaming at me the entire time.
Once my mom and I reached the main lobby, I practically hopped on one leg over to the wheelchairs which sat lined up for hospital guests to use.
Relieved, I let my weight sink down onto what looked like the soft cushion of the seat, only to realize with a rude awakening that the cushion was not so much a cushion, so much as a piece of fabric stretched over a metal bar.
The back of my right hip (aka my right butt cheek) slammed down super hard on the metal bar, and I jolted back up immediately, convinced that somehow I had just been injured. I didn’t know how exactly, but I had never felt an impact of that force anywhere on my body, and it somehow didn’t make intuitive sense that I could walk away from it without somehow being injured.
But no injury was immediately apparent. I thought for a moment that I ought to be asking them to x-ray my pelvis, rather than my knee, but I sort of went into denial mode and just tried to forget about the pain and see what happened.
Three days later came the very first time one of my sacroiliac joints locked up.
I have since read that trauma to the area, particularly in a way that is asymmetric and disproportionately impacts one side, can push the bones of the pelvis out of alignment and sprain the ligaments that normally hold the SI joint in place. And one you stretch those ligaments out, they are never really completely able to hold the joint in place optimally again.
Possible Factor #3: Chiropractic adjustments
After struggling with SIJ dysfunction for five years, I came to realize that the chiropractic adjustments I’ve been getting regularly for my SI joints for these past five years have actually been backfiring and somehow making things less stable overall.
As I wrote here, although I do think my chiropractor is skilled at identifying where things are out of “alignment,” and although I don’t think the adjustments were technically injuring me in the strictest sense of the word, it does seem that they were ultimately serving to destabilize the area. I think it’s possible that they were putting too much force on the ligaments in my pelvis, and slightly straining or stretching them out so they couldn’t hold things in place as well.
Looking back, I remember that I had actually already been going to see my chiropractor back in 2011 before my SI joint problem started. I remember I had started to get some much more mild back pain, which I had attributed to the fact that I was walking funny from the knee issues, so I had been hoping my chiropractor could fix that.
I think the wheelchair incident was definitely the watershed moment, but I think all the stress that had been placed on my back by months of limping, and generally being out of shape, combined with the force of the chiropractic adjustments, ultimately came together to set me up for failure as well.