Had surgery on my knee approx. 18 yrs. ago. Was told then I would develop arthritus in that knee. Have recently twisted the same knee. Was sent to therapy and had an M.R.I. with die imageing. The doctor that did the MRI in his report said fresh tear in the maniscus and the beginning of OA. The surgen that I was sent to said the OA was extensive and that he didn't feel that the tear was fresh. He gave me a cortizone injection and said the heavy jell injections didn't work. Is he correct? The cortizone injection does not seem to be working all that well. Should I ask for another cortizone shot?