Replying to PRP therapy / Stem Cell Therapy

I was wondering if anyone has heard of or had PRP therapy, and what their outcome was with it? It looks like a great alternative to surgery for a lot of injuries-reducing the recovery time to only about 2 weeks and strengthening, tightening, and healing the muscles/ligaments.

I've had 2 and a 1/2 knee dislocations, and am aware that I most likely need surgery. I am trying to give it one last go by strengthening the muscles around my knee as much as possible.

If anyone has had PRP/ stem cell therapy for any kind of injury please tell me how your experience and success rate with it was. Thank you!