I don't know for sure, but it may be that they replaced the top of your femur AND lined the pelvic socket with metal. Metal rubbing on metal will shed ions. THRs and TKRs these days are done with metal on polyethylene (plastic) prosthesis. In the case of a THR, the socket is smoothed out and then a polyethylene liner is put in place.

I can't be sure, but if you are metal on metal, it's probably time for a revision.

(I had both knees replaced and they use polyethylene spacers where the menisci were. So no metal on metal. and my surgeon used the Mako robotic assistant.))

All the best to you.

Joe