Re: cyst in hip joint
Two things, a cyst related to osteoarthritis (wear n' tear arthritis) which would be treated by treating the OA and possibly draining the cyst. If the hip degeneration was severe enough, by hip replacement.
Secondly, you said, "its not benign . . ." Not benign means cancer - was that a typo? A bone cyst related to bone cancer is totally different from a little osteoarthritis cyst.
A burst cyst wouldn't cause infection though it could be very painful when it happened - you'd probably pass out. The fluid that isn't immediately absorbed by the body would drain through the lymph canals into your leg. You'd have some swelling for a few days till all the fluid was completely absorbed.