I have a client with a double hip replacement, and Nancy is correct about the age of the replacements. Mine should not cross over her center line or perform exercises that externally rotate/expand her hips beyond hip distance (think plié squat). Her replacements are about 20 years old. If your potential client becomes a client, I would consult with her doctor to get any limitations.
I’ve also had clients with a double knee replacement–same concept about consulting with her doctor, but I’ve not had any limitations there (each client is different).
Best to you,
How old are the replacements? (newer ones can have way better ranges of motion – I have a client with a double hip replacement who has very good movement, including crossing over her center line as approved by her doctor but not do-able with older replacements)
What does her doctor say?
This is a case where I would request a doctor or PT note.