The thin, slippery layer of cartilage between the bones in the knee is magical stuff: strong enough to withstand a person’s weight, but soft and supple enough to cushion the joint against impact, over decades of repeat use. That combination of soft-yet-strong has been hard to reproduce in the lab. But now, Duke University researchers say they’ve created an experimental gel that’s the first to match the strength and durability of the real thing.

Many people could benefit from something like this. Currently knee replacements - which involve pretty invasive surgery - may only last for a couple of decades before they need to be replaced again. 

https://today.duke.edu/2020/06/lab-first-cartilage-mimicking-gel-strong-enough-knees