The stuff they can do with 3D modeling and manufacturing is pretty awesome. I'd imagine they use some sort of FEA to balance loading. Between the really good polymers and metals (& metal finishing) it's really astonishing what they can crank out on a near assembly line basis. I'm guessing the cylindrical parts that mate into the milled out slots in the bone are a sintered metal, that the bone will grow into. That's how my hip was (sintered finish, not the same geometry).
Not only is medicine remarkable, but availability is pretty good too. Look at the wait times in the UK. We're truly blessed to have what we have.
OP, if it's like hip replacements, they'll give you a little card to keep in your wallet with details on your new part. You'll have to remember when you go through metal detectors that you'll probably set them off. I tell guards as I approach any metal detector "fake hip" and pat it. They wand me and away I go. I didn't know they had fake ankles and I'd guess some security guards won't either. They'll wand you but keep the card handy just in case.