I honestly don't know where the support for saying Regenexx is "shady", comes from, nor do I understand the reluctance to try Regenexx over ACI. (Yes, 15% is a high failure rate, and does not indicate anything about the percentage who make a "full recovery")
ACI or microfracture, or whatever other surgery one is considering is likely going to cost a few thousand after all expenses are considered. I'd rather pay the $9000 (assuming I needed three Regenexx SD procedures), given what I know about stem cells and their (successful) applications delineated by Dr. Centeno and others (in other fields of medicine).
How anyone can turn a blind eye to Dr. Centeno's continuous updates on his Regenexx webpage is beyond me. It's not like he only has a few cases (he has hundreds), or that he tries to hide the failures (on the contrary, he points them out).
I am also going to put this out there.. upon viewing other sites I have noticed that there are shills hell-bent on discrediting Dr. Centeno's work due to "insufficient evidence" and "lack of FDA approval". Some of them are somewhat versed in molecular biology, and can fool those who are not due to their background. Some are just so good at debate, that they can convince well. And some are just doggedly and vitriolically screaming something to the effect that Dr. Centeno is a quack.
It's all interesting to watch for various reasons. However, I will be the first to say that each individual should CONVERSE with advocates and detractors alike, and carefully analyze not necessarily what is being said, but how.