I'm not sure if all hip replacement parts are titanium, but I was told when I had my 5 level cervical fusion in 2004 (which left me with 10 screws (c4,c5,c6,c7,t1) and 2 rods that titanium did not trigger metal detectors? They did give me a card to carry saying I had orthopedic implants in case.

I'm hoping to wait for further advances in med. tech. that will coat the bone to bone areas in the hip with teflon or something. They are doing that with some success in knee operations and other joints, I read a while ago.