metal used in hip replacements?

I should know, but it's Saturday and physician's office is closed. I'll ask Monday but I don't know what kind of metal he put in my hip for hip replacement surgery. I have a question which he may or may not be able to answer, so your input could be helpful. Since I have metal there I was looking at putting magnets on my thigh and knee to reduce inflammation. I don't know if it works, but I am wondering if it's safe.