[vervez]

Bioengineer here able to chime in with niche expertise. Cartilage is and has been a holy grail in biomedical engineering but is very difficult to grow and transplant. There have been some successful neo-cartilage projects but integrating that into a defect and successfully integrating with host cartilage is the problem. The boundary of the defect actually has electronegative components that actively oppose integration of host and transplant (synthetic) cartilage. I think the most likely solution won't be a tissue-engineered transplant but rather an active cellular component that appropriately responds, and builds upon, this negative feedback cycle via cellular programming.

[xwdv]

Could we harvest cartilage from other animals? Such as pigs perhaps.

[vervez]

That's a strategy but there are issues with immune rejection since that's a xenograft. I think there are some products based off of this concept for other areas (skin grafts) after removing all xeno-cells from the tissue, but articular cartilage is more difficult to remove/replace xeno-cells with autologous or allogenic cells.

[scheme271]

I think cadavers are the typical source. Since there's no blood vessels in it, tissue rejection isn't as much of a concern.