Poor Pearly has OCD

Pearly woke me up at about 2am. She was whining and crying and was lame on her left front leg. Even when she was laying down she was moaning, crying and shivering. I took her to the vet and he has preliminarily diagnosed her with OCD (osteochondritis dessicans). This is the 3rd time I have had her in for lameness in that shoulder since last March. Last time x-rays weren't conclusive but now she is having pain even at rest. He prescribed Rimadyl,Cosequin DS and rest for the next 2 weeks. If no better then the next set of x rays will have to be under anesthesia. If we can't control the pain she will need surgery. Has anyone here had any experience with this? I have been looking at things on the web and I understand the process. I don't want uneccessary surgery but on the other hand I don't want to make things worse by waiting. I hope the Rimadyl kicks in soon. She beside me and whimpering. yvonne