Hyaluronan
"While doing a twist in Zumba in January I felt a pop and terrible pain in my knee.  I was in great pain when walking, for a month, with a knee I have never had a problem with. When I went to the orthopedic Dr he told me I was bone on bone and a candidate for knee surgery.  I am 68 yrs old, very active and have never been overweight, I was shocked at the diagnosis.  Cortisone gave me no relief.  Starting in March I had one injection for 4 weeks, with minimal relief.  A month after the last shot (middle of May) I got out of bed with 90% relief and a bit more improvement for 5 to 6 days.  It is now 5 months and I am almost pain free!  I will have this again when it wears off."