I was surfing the internet and saw your question and though I would respond. I just had an ultra sound guided PRP injection two days ago so can't answer your question exactly at this point but certainly can keep you updated with my progress. My labrum tears are from 20 years of long distance running so just due to wear & tear and not from an impingement, probably similar to you. I turned 45 last year and I swear my body started falling apart. I had an MRI to confirm the tears in may and stopped running completely by august as even a 3km run was excruciating both during and after. I can't even hike for over 1.5 hours without post exercise pain but can seem to bike for 2-3 hours without any issues.
My sports physician thinks PRP injections may become a commonplace procedure in 5-10 years but right now they are not overly popular in Canada and even my physician friends are unfamiliar with the procedure. Although I should remark my sports doc did not do the procedure or even recommend the orthopaedic surgeon who did it. I happen to visit the surgeon for another matter & he then mentioned he did the PRP injections. I did a bit of research and then decided to try it. I live in Ontario so I paid $385 per hip for the procedure because my provincial health care covers the injection part just not the blood withdrawal and separation in the centrifuges. I had a good concentration of plasma but not a lot of it so I may have to go back & get a second set of shots in a month.
I am really hoping the PRP injections help heal the labrum although I have already decided my running days are behind me but want to continue cycling, hiking, strength training, etc and really don't want surgery.
I'll keep you posted on my journey with the PRP.