Actually, my husband had 2 knees needing TKR...he decided to have one done and then have the other one done shortly, but in the meantime, starting taking the Glucosamine/Chondroitin...the 'bad' knee stopped hurting...SO...I decided to do it, as well. I have a pain management doctor, and I told him I was taking it (it's over the counter) and his response was, 'I have many knee patients who have taken it with a lot of success.' So that's why I started it!