Do a web search for cartilage transplant.

[Darkius]

Doctors now have an approved procedure to take cartilage from a non load bearing part of your body and clone the cells and implant them in your cartilage cracks. Or they can get donor cartilage from knees that came out of people with total knee replacement.

I'm glad I did not get a knee replacement. I have many cracks for them to put cells into.

[Heisman2]

I don't follow this literature but there is definitely lots of theoretical potential for this type of thing. How much does this approved procedure cost?