I had patella tendinitis and once it got in there it was a bugger to get rid of. I would rest until the pain went away. As soon as I resumed activity it would come back. Finally knocked it out with steroids. There is cartilage on the back side of the knee cap (patella). Apparently you can grind it right away until you have bone on bone and then you are pretty much done. Hope that’s not where Buck is at.