Congrats for finally getting the approval and prayers for it going well. When I have heard of some not going well, it has usually been because of the patient not following the doctor's orders and those of the physical therapist after the surgery. Do not try to do something you are not supposed to too early. Occasionally there can be some infection from the surgery but that seems rare. Most have been very happy afterwards and wished they had done it earlier but they were questioning it for a while after the post-op and during the therapy.