Researchers at Columbia University Medical Center & Cornell are working on a method of regenerating knee meniscus in place. It is a combination of 3D printing and getting stem cells to do the regeneration.
Interesting as the 3D printing is, the key is the way to hold two growth proteins that atttract stem cells that do the work. They successfully did this in sheep so that they could walk, but a few years are needed in the lab to make it practical for you and me.
Photo: Tech Crunch