Allie, regarding your mom's hip replacement: If she has fallen since having it, something could very well have slipped out of place and is causing the pain. If it were dislocated, she would not be able to bear weight on that side at all. Since she doesn't follow through with appts., I doubt she's been in for x-rays. When I've had hip replacements and revisions, I've had to go in for f/u x-rays and visits at 6 wks., 3 mos., 6 mos. and eventually just once a year.
A fall is the worst thing that can happen to a hip replacement patient. If she complains of hip pain, insist on taking her in for an x-ray. If she refuses, then there's nothing you can do.