Good to heqarr the DO's movement worked for you.
Not sure where you live but check out National Spine and Pain Centers ... My treatment was at one of their affiliated centers in Chevy Chase, MD. And if you want to check our prolotherapy check out the website for ProlotherapyNashville. The Dr. there has some good explanations.
The idea is that the irritation of the shots tells your body that something in that ligament needs to be fixed and initiates the body's own healing system that for some reason has not done it's job. For me, my hyperextending SI Joint relied on the attached ligament and that damaged it. It became "lax" and could no longer do its job. I also had the leg length differential fixed by an operation on the other hip after a fall on the ice. UGH! Now I can put it back from it's small extensions by pulling a knee to the chest and keeping my major leg muscles in good shape. The subluxing leg stopped after the prolotherapy!