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Comment by andyidsinga | Hacker News Reader

"Conventional knee and hip implants have to be replaced after about 10 years due to wear and tear."

this is really amazing to me! you put metallic, designed-to-last object inside an organic blend of tissue and bone and human activity and in 10 years its worn out. So much opportunity in the area!

Along the same lines, interesting how delicate our bodies are in the short term but rather durable in the long term.

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Your own body basically goes through a skeleton every 7 years, although it's a gradual procedure of course. Your bones are constantly being eaten away, and replaced as part of their maintenance. It's truly amazing, but the secret is definitely, "We can rebuild it" not "Unbreakable".

So much for wolverine's longevity.

Would it be possible to coat a human bone with this new alloy?

Are you planning on becoming Wolverine?

No, I'm too tall.

Don't give up so easily. According to Marvel[1], Wolverine is only 5'3, but Hugh Jackman played him at 6'2. For me, the most surprising stat from that page is that he weighs 195 lbs without the metal skeleton, and 300lbs with. He must be insanely stocky for that height.

1. http://marvel.com/characters/66/wolverine

He has at least 80 lbs of sideburns.

Fun fact: Australians are naturally taller, as a result of being suspended upside-down on the bottom of the planet!

unreliable narrator

I think that the defining characteristic for Wolverine is the regeneration rate, not the metallic skeleton (which has as a prerequisite the regeneration rate).

The bone is a living organ coating it with stuff can kill it.

I think there was a darpa paper about surrounding bones with carbon nano tube meshes that would renforce them, prevent or reduce shattering and could be used as an internal cast with minimal fixture but I hope we never get to that point.

Why do you hope that we never get to that point?

Would be pointless, the coating would just wear off.

Yes! .. i love thinking about things that way!

Speaking about that mentality > the right to repair : https://news.ycombinator.com/item?id=12088631

...raises the question about who can service and repair medical implants. I imagine pace makers would be an interesting case study.

I imagine any inorganic implamt is going to degrade, and have proprietery patents included. Your last question reminded me of the Jarvik Heart, in particular. Interesting read on evolution of the permanent to impermanent artificial heart:

http://mobile.nytimes.com/2016/03/21/us/artificial-hearts-ti...

that is a great read, thanks!

It really only avoids being an issue now because of the nature of surgery, the longevity of typical patients vs. implants, and so on. Hopefully, eventually, both of those factors will change and the law is going to be shown to be woefully behind.

Hopefully, somewhere, there's research to use the body's own maintenance and repair to maintain an artificial limb. That'd be the ideal.

Regenerative medicine is the goal, and hopefully the future, but it's not easy to get right without accidentally setting off cancers or immune responses you didn't expect or want.

I thought that's why coral was used for bone implants it's first shaped like the part needed then once implanted your own bone cells gradually take over.

Maybe it was just a trial I saw to see if it worked or maybe it can only be used for small patches not entire sections of bone like a femur or hip joint.

No, you're absolutely right. Coral is porous, and pretty biocompatible. It's the same thing that happens with a graft from a cadaver!

makes me wonder about 3d printing with powder-compound coral or cadaver bone - potentially even with very simple FDM 3d printers.

I was astounded to learn about the composite materials being developed for cheap 3d printers - see http://colorfabb.com/ and https://ninjatek.com/products/filaments/ninjaflex/

TIL something really cool, thanks.

We should adjust our justice systems to this cycle. You can sit in jail for max 7years. After that you are considered a different person. The justice apparatus needs to use that 7 years to form this new person in a way that it can behave according to the outside system.

There's something to what you're saying here! - the justice system, and the people involved with it need a real change in mindset.

It isn't that you might be a different physical person after 7 years, but a different person based on the current context!

There was a great invisibilia podcast on the subject : http://www.npr.org/programs/invisibilia/482836315/the-person...

See also (referenced in podcast) : http://www.columbia.edu/cu/psychology/indiv_pages/mischel/Wa...

While lots of hip and knee prosthetics last longer than 10 years, too many don't. The implants use synthetic materials to replace both sides of the joint, so there isn't for example, a metal femoral ball running against the patient's original hip socket in a hip prosthetic. It's metal/metal or metal/plastic.

I've done a little work in prosthetic materials. It's amazingly complicated. There are metals, plastics, and ceramics as basic options. There is every combination of one of those running against the other in hip implants. There's at least a half-dozen variants within each of the three materials classes. Typical materials are CoCr (metal), Al2O3 or ZrO2 (ceramics) and radiation cross-linked ultra high molecular weight polyethylene (UHMWPE plastic).

Prosthetic lifetime gets more and more important as the population of recipients gets younger. They're more athletic, put more load on their implants and they're going to use them longer than the earlier, older recipient population.

Yes, serious opportunity here. I hope implants are a once in a lifetime procedure if I ever need them.

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