Anyone have any experience with this? What was the treatment? Advice is welcome. Thanks in advance!

I am dealing with this same issue.  I haven't done anything yet.  However, with the swelling that has occured to this point I will be getting an appointment with a performance vet and looking for more information and options.  My vet says that they can make an incision to cut the Annular which will let the ligaments move freely following healing and my mare should be able to go back to work, after recovery / rehab.  My vet has done this procedure before with good results. However, I want a specialist / surgeon to give a second opinion (sono or MRI) to see exactly what is going on inside prior to a decision and course of action.  FYI my mares Annular ligament is restricting the movement of tendons and causing swelling (think windpuffs), but on the front leg.