In this video, a spine surgeon explains the differences between SI joint dysfunction and inflammation.
Basically, he explains that dysfunction is more of an umbrella term, referring to the fact that the joint moves abnormally because the ligaments have become stretched out.
However, when ligaments become stretched, they also tend to be inflamed, so the two can often go hand in hand.
This video is from Zyga– the company behind the SImmetry surgical procedure. They’ve got a lot of informative videos on Youtube.