Revision of Birmingham

[Hipsterpain]

I got a Birmingham hip about 10 years ago. From day one I have had a bad hip flexor. I have asked the Dr. and he thinks the hip flexor is riding up on the artificial joint. I am a little guy and I think the Birmingham is just too big. I have also had a traditional hip on the other side about 20 years ago. That one is great. My Dr. seemed to be confused about a possible revision going to a smaller traditional hip replacement, as the size of the cup is now too large and Dr. did know if there's a way to make the cup side smaller for this. Does anyone know anything about going from a Birmingham to a traditional artificial joint? Thanks.