I'm sorry, don't know much about it, in fact I've never heard of a snapping hip......looked at the font of most knowledge and found this....
snapping hip sign - General Practice Notebook
In GP land, we used to try our upmost to prevent surgical intervention for some orthopaedic problems, (unless "barn door")-as the long term results weren't always proven. The technology is now improving, but I'd hazard a guess that surgery probably isn't the best option at this stage. The jabs tend to work initially, but in my experience, tend to be less effective, the more they are used.
The usual interventions included weight loss, exercise, nsaid's, physio etc.
It sounds like you're doing your bit though. Interesting to hear about the "competitive stuff."
You don't mention your age, but could it be time to listen to your body, sell the karate gear and purchase some golf clubs?
Less impact, more fluidity?