It has been over a decade since I worked on any MR project, but iirc, the dicom data should have bone density in it. You should be able use it as an average like JimC5 wrote.
Unless of course you are trying to design custom hip implants based on patient-specific bone structure. If that is the case, you would probably be best to develop your own proprietary software for the job. Other than that, cadjunkie is correct that dicom data can be converted to stl.