Mark, so sorry to hear your mom is having tkr, but, it will go well.
I am an older woman, and just had my second total hip replacement and a few years ago I had knees done one at a time. So at the age of 65, in the past 7 hears these 4 joints have been replaced.
Tell your mom, it will hurt like crazy, but, well worth it, just use her walker for 6 weeks, and keep up with the therapy.......She will do great, best of luck to her and you have a smile and that will encourage her.
Roboticlady