future knee replacement

first off, I have loved your workouts for a long time. the only problem is that i have issues with arthritis and other joint challenges. i know joint replacement is in my future but want to put it off as long as possible. you guys **love** your squats, lunges etc. (i kind of, too) however, i have noticed that there are many people using fb that probably deal with similar issues as i do. would you consider making some series of routines for those who are restricted from those types ofexercises but still want to look, feel and move as good as we can??? i'm currently doing fb30, but find it sometimes nearly impossible because of knee and ankle pain. thanks for ALL you have done and do for this community!!