Is there any possibility that a pain pump can be inserted to the hip joint for pain control?

My 85 year old mother has severe arthritis that is almost to the point of the joint being frozen. It causes her severe pain regardless of the pain medication regimen she is on.

She has waited too long to have the replacement surgery. She now has coronary artery disease that can only be controlled by medication as well as irregular atrial fibrillation.

She had a cadiac catherization and was told she was ok for the surgery. But the Cardiologist gave her a very poor risk factor for either suffering a stroke or a heart attack during the surgery. Her pain is so bad that she stays mostly in bed. I tried getting her to do physical therapy to strengthen and condition the rest of her body, but she lost interest in that (did I mention she is very stubborn?)

I don't think she has the strength to go through the rehab now if she did have the surgery. This is why I am inquiring about an implantable pain pump.

Any constructive thoughts or advice?

eff