good luck. i would take the above posters advice lol. i have sacroilitis as well but its due to ankylosing spondylitis and poly arthritis from an auto immune disorder. mine is nothing mechanical. the two are one of the same but treated very differently. do u think physical therapy could help? if its not aligned right it may be causing the incontinece. OR you may just have an underlying bladder issue.. but if theres no pain in ur bladder i would say its prob the hip issue.
good luck !! :)