Sounds interesting. My wife has had one knee replaced (2017) and now desperately needs the other one done, but the doc has been dragging his feet. Her next evaluation is in July. She can barely walk with a cane now.
You could have her try tablets of Glucosamine/Condroitin/MSM 2 in the morning and 2 at night, with some food. There are also a number of other supplements that can help general physical health. I was already taking a number of them/ Then when I was 82 I hurt my knee crawling out a small window to fix the roof. I bent my knew too tight and felt a pop. It hurt a lot, but I added the GCM and in a year my knee was good as new. I am 86 now.