There's those blade foot prosthetics that make a
no-legged athlete, who had barely trained in running, able to outrun Olympic runners. Turns out he killed his girlfriend and was let out on bail despite the fact his main claim to fame is
running real fast. There are also
robotic hands that can feel sensory inputs. I recall one interview with a researcher saying that the big problem with robotics was that they can give you a really strong hand, or a really dextrous hand, but it's difficult to do both. Although a weak dextrous hand is probably good enough for most people, once they break that design barrier we're good to go.
There's various stuff going on about exosuits to help soldiers carry very heavy loads (such as armor and ammunition, but also just gear so they can remain in the field longer and not get so tired). We have brainwave-controllers that can allow a quadriplegic person move a cursor around a screen - which is about 20 years away from being completely incredible.
Part of researching how to make a replacement part is being able to make a whole robot that works well. There's the robo donkey that a guy shoving on it can't knock over - it's too agile and just rebalances itself. Thing can follow its people on its own and carry huge loads, navigating novel broken terrain well. We have that dumb dancing Honda robot. Spider robots, etc.
They've found a few different ways to make undifferentiated stem cells without harvesting from babies. I read something recently about one research team that was able to get differentiated cells to revert to an undifferentiated state, from which they would naturally differentiate depending on environment much like a stem cell. They
stressed the cells with acidic solutions which killed many but undifferentiated a large percentage. The trick is they were differentiated cells from newborn mice. They haven't reported on attempts to do it with older cells in more adult mice - but note they didn't just take stem cells from a baby mouse. This is very exciting stuff but it's in the earliest stages still.