4 years ago I could only walk with crouches due to pain.
Last month I competed in 2 half-marathons.
I was able to get much much better by doing a lot of PRP (platelet-rich plasma) injections over past years and a single SVF (stromal vascular fraction) injection 1.5 years ago.
My MRI shows that cartilage has grown back significantly (not fully, but I no longer have a gaping hole in it).
A generic advice that I learned is that muscle-strengthening exercises help A LOT. Basically muscles form a protective corset around your knee and reduce the stress on your joints by a lot.
Also, arthritis often happens due to low blood flow, so as painful as it may be, you have to keep moving, try not to sit too much.
Another generic piece of advice is controlling your weight, this is just simple math, the less you weigh, the less stress your knee receives.
What also worked for me was hyaluronic acid injections, when I was in a lot of pain and it was hard to work on my muscles, hyaluronic acid helped to reduce this pain by being a good lubricant. Probably I am going overboard with it now, but I keep having injections every 3 months just to be safe. It can be of different concentration and volume. If you inject something with a smaller % you have to do it multiple times in a row with 5-7 days between, if you inject something with a higher % then a single injection is okay.
The PRP / SVF part you already read about. I am also a 31 yo, so while I am young my body is better at regeneration, I don't think elderly people get the same effect from these. I did 3 sessions x 5 PRP injections with 6 months between sessions. The effect is by no means immediate.
It's certainly a hard road, but better than a wheelchair.
Adequate stress on joints from right exercises executed in good form are part of this. Beginners almost never got this right and overdo things, investing into professional help in the beginning is very good idea.
Same with weight - when people react to degrading health due to say being obese, one is beyond point of return in many things comprising overall quality of life and health. Like getting your act together after first heart attack, way too late.
If in pain, generally don't exercise through it, body is saying something ain't right so rather address it. Try things like swimming which put very little stress on the knees yet can work whole body efficiently. You really want to have all parts of body developed well, otherwise you will be always chasing some degradation like whack-a-mole without ever winning.
You essentially get a completely new joint surface from a donor and have to be in crutches for 3 months but it was 100% worth it for me. I refused to do fusion and avoided any doctor that said nothing could be done.
https://pubmed.ncbi.nlm.nih.gov/31045670/
Another solution for end stage ankle arthritis is distraction surgery but I didn't look into it much but it could be useful too: https://www.hss.edu/conditions_ankle-distraction-arthroplast...
I was doing them back in Russia and a PRP injection there would cost around $80.
I keep doing hyaluronic acid injections every 3 months just to be safe, whatever I am doing it seems to be working, so I continue doing them. Right now I live in Georgia they cost around $105 here ($90 for the syringe, $15 for the doctor).
SVF seemed to have a much stronger effect than PRP, it's hard to quantify, but I would say a single SVF felt close to all the PRPs I did before.
I think it's worth it considering getting a paid surgery in a "2nd world" country, like Kazakhstan, Turkey, Russia (pre-war, feels uneasy going there now) and etc. Things there cost 10 times less and most surgeries, where hospitals don't need very advanced equipment, are probably done on the same level as "1st world" countries.
Glad you were able to rehab so well!
With SVF they make you a small liposuction (around 80 ml if I am not mistaken, local anesthesia), then also extract cells from it that are similar in function to stem cells and inject them into your knee.
PRP is very noninvasive. SVF is more invasive, mostly the liposuction part, but I'd say it's still walk-in the part if you compare it with something like arthroscopic surgery.
There was no pain during them, but once you cool down you feel all the beating you received.
I mean, I am still not 100% healthy, I get some swelling after exercise, and I don't think I can compete with anyone doing it seriously, I just can't get the same volume of exercise a healthy person can. Like, I can only run 10-16km every 2 days, because I need to give my knee time to recover, while a healthy person can run it every day.
But hell, just some time ago I was looking with jealousy at people running at all.