Hi Marilyn @marilyncarkner, Both of my knees were bone on bone from degenerative arthritis but the pain was severe in my right knee so I ended up having a knee replacement at Rochester Mayo. Prior to the knee replacement I discussed both synvisc and possible stem cell treatment with the surgeon and was told that when the joint is bone on bone the treatments aren't recommended. Here's more info:

Synvisc effective when patient has bone on bone in the joint?
https://www.hopkinsarthritis.org/ask-the-expert/synvisc-effective-when-patient-has-bone-on-bone-in-the-joint/
Having my right knee replaced has been one of the best decisions I've made. So far my left knee is without pain so I just try to keep the leg strong with daily exercise. Hope this helps.