Due to an injury, my horse hip likes to rotate to the right, so it looks dropped. It was pretty bad. It was causing mild lameness that no one could pinpoint, but I hadn't yet done a specialized lameness exam.
My horse's chiropractor found it and fixed it. The next day, lameness was gone. But the ligaments are weak, I guess, because it is a bit of a chronic thing. It does slowly slide back, but nowhere near what it was before it was diagnosed. And with proper muscling building up now, it should, in the future, keep things in place. But I imagine it'll always be a thing with him.
Find someone that does manipulations with amazing reviews. Your chiro should've given you some thoughts about it. I first had him looked by at a certified chiro vet, and while she noted it the hip was dropped, she didn't do much. It took someone who does manipulations but isn't technically a certified chiro to actually successfully help him and put him on a successful rehab program.
So those are my thoughts. And we're doing dressage and it doesn't seem to be holding us back at this point. =)