My orthopedist has begun the preapproval process for me (right knee, lateral osteoarthritis, Stage 3) for the same injections. He said that my carrier (Anthem Blue Cross PPO) would deny the first request, and then the *real* approval fight would begin, and we would know in four to six weeks.
The doctor said that 60% of the patients have a good result with the series of shots (three to five shots, spaced a week apart), and that it takes a little time (a few days to a week or so) to know if it is working. "Good results" means they had much-reduced or no pain for four to six months, and could repeat the shots at intervals for several years before they stopped finding relief.
I will keep you posted on whether or not I get approved, and the results of the shots. I figured it was worth finding out sooner, rather than later, as I am very reluctant to go down the cortisone-shot route.