I use to be very fit. Even worked as an instructor, years ago. I have had 4 total knee replacements on my right knee within a two year period. I now have chronic pain in my rt knee. I have lost full mobility in the knee also (ex.) Cannot make a full revolution on a bike. My leg will no longer bend to cycle a bike or go down steps without moving one at a time. I have gained 40lbs. Over weight. After any work outs I am in severe pain. Can anyone help?