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Interesting related article I think I saw here a while ago:

Healing of acute anterior cruciate ligament rupture on MRI and outcomes following non-surgical management with the Cross Bracing Protocol

https://bjsm.bmj.com/content/early/2023/06/13/bjsports-2023-...

TL;DR they braced the knee at 90 degrees flexed and saw evidence of some healing in 90% of enrolled patients after 3 months

Isn't this common treatment already? Don't actually know, just remember my stepmom and everyone else I've known that had knee surgery getting a cool knee scooter thing to roll around on for the months long recovery period.
No, this is instead of surgery, as far as I can tell just splinting it bent at 90 degrees to allow it to heal.
My wife healed her fully severed mcl without surgery. It's difficult but possible. You have to be really disciplined and follow the protocol.
From what I gathered from the article abstract I posted above, this is unique because it's a protocol for healing a fully severed ACL, where the MCL heals much more readily than the ACL apparently for reasons of blood supply and positioning.

I love it when doctors can use conservative treatment to avoid the need for surgery though, very exciting when a natural process can do the work.

If you have any anecdotal discussion from your wife's experience I'd be interested to hear more about it - I haven't banged up my knees yet but it's just a matter of time, already down some functionality in an ankle.

Yes, although if you have a few million and access to a daily MRI you can even heal a PCL this way. See the Connor McDavid documentary "Whatever it Takes".

For my wife, it was strict bracing at specified angles with forced stretching to retear the tendon at periodic intervals as it healed. She was on advil and a cryo cuff immediately after injury which really helped. I'd recommend having a cryo cuff on hand or a plan to quickly get one if knee injuries are likely in your future.

Look into red light therapy for ankle, for example: https://a.co/d/7CPLFkl

This seems to be saying that a completely torn ACL will actually reconnect if the knee is kept immobilized? I did my ACL and in the MRI it was just gone aside from a fuzzy puddle on top of my tibia, it'd be incredible if that could regrow.

> knee immobilisation at 90° flexion in brace for 4 weeks, followed by progressive increases in range-of-motion until brace removal at 12 weeks

Compared with an ACL reconstruction with Gracilis tendon graft (the procedure I had), I wonder if complete immobilization for four weeks might do more damage than just having the surgery. I was limping but still loading up the leg as much as possible for four weeks after the accident and then off it for a week after surgery, and the muscle loss and general degredation was severe. It took months of physio and most of a year of exercise to rebuild back to ~95%. Taking 2-3 months to get weight back on it sounds light it could be worse overall.

If it grows back "correctly", that's still way better than surgery, since who knows if they "get it right".
That's no more convincing than "If the surgery 'goes well,' that's still way better than just leaving it, since who knows if it grew back 'correctly'."
Is "rupture" a full tear? The "common knowledge" is that "ligament full tears can't heal". In fact, 10 years ago, people were told that partial tears can't heal either, and you might as well not bother.
>Is “rupture” a full year?

Yes. Complete discontinuity of ACL fibers on MRI.

They claim they can prevent them from being rejected with their "special sauce" which they won't reveal.

What else can this be other than washing away all of the cells and leaving behind only the scaffolding? Decellularization is already a thing for tendon xenografts. Maybe they have a unique way of doing it but that's pretty doubtful. In general this field is getting close to large scale use in humans as it is.

Oddly, there's already a different Australian startup from another university doing extremely this. https://www.imcrc.org/blt-allegra/

Lo and behold, the patent [1] says:

> [0038] In preparing the xenograft for use, the tendon is surgically dissected and removed from the paratenon (tendon sheath). The tendon is composed mostly of an extra-cellular collagen matrix, which is non-immunogenic. The tendon may therefore require no denaturing (decellularisation) prior to implantation into a mammal. In some embodiments, the tendon may be subjected to a decellularisation process prior to implantation. In removing the cells from the tendon, the immunogenic antibodies within the cells are also removed, thus rendering the tendon non- immunogenic. Methods of decellularisation of tendon tissue are known in the art. Such methods include physical, chemical and enzymatic treatments, wherein the cells within the tendon are lysed, leaving an undamaged extracellular matrix having the same physical and biochemical properties as the natural tissue.

So it is decellularisation, they aren't claiming any particular decellularisation method, but it's quite possible they have some particular recipe for decellularisation which works well, and which they are keeping secret.

[1] https://patents.google.com/patent/WO2019014698A1/en?oq=20179...

> They have also developed a way of ensuring the kangaroo xenografts are not rejected after transplant. The key to this is what he describes as “the special sauce”, and it is a closely guarded secret that has already been patented.

PATENTS DO NOT WORK THAT WAY!

Anyway this appears to be it:

https://patents.google.com/patent/WO2019014698A1/en?oq=20179...

I love it when people do this "patented secret" thing. Patents are public for very good reason - society protects ideas that are documented publicly so that the public knowledge is improved after the patent expires.
Like most (all?) governments the U.S. government has a strict set of rules that it must follow unless it decides it doesn't want to.
Well sure. Because if the US govt's patent on hypersonic rocket propulsion (as a conjectural example) were public knowledge, it would be trivially simple for their rivals to use that information in their own programs or countermeasures.

Surely it's evident that most nations would find an imperative in keeping that knowledge guarded?

The govt doesn't have to patent these techniques at all. They do so for the benefit of public enterprises (so contractors and military industry can benefit) and so that the knowledge does eventually enter the public commercial sphere. That article itself mentions multiple patents that eventually had the veil lifted and/or expired.

How do contractors benefit from the patent?

They can "eventually" release the information whether or not they had a secret patent.

they "benefit" by agreeing to play ball getting the (often absurdly huge) defense contract.

and since the contractors are taking federal money, the gub'mnt reserves the rights to any of their findings; agree or don't get the contract.

but this then gives the Gov another angle if the contractor deliberately or accidently releases or sells those secrets -- not just distributing classified materials, but also patent violations, and potential lawsuits. it's a tool to ensure compliance if/when the government is funding stuff they don't want released

It allows Boeing, for instance, to patent their version of hypersonic propulsion (again, a conjecture, not a real example) without worrying about the information becoming public knowledge; which a non-protected patent would require. Government or agency patents are a matter of course and provide attribution and protection to their authors (similar to public patents).

There are plenty of technologies the US govt researched and implemented that they did not patent and instead released directly to the public domain. Many of those related to Arpanet and baseband cellular technologies are key examples. So your point is moot. They do both, it's discretionary to their strategic interests, in much the same way commercial entities will sometimes patent their research but make it freely licenseable.

Ah, yes, ahem, I definitely understood exactly what that patent is saying, but perhaps you could summarize it for all the other people who can’t parse a patent immediately?
It basically confirms the theory discussed in this thread:

https://news.ycombinator.com/item?id=36785816

In layman's terms, they're using achilles or tail tendon from certain kangaroo species that have been carefully dissected to retain only non-immune-reactive tissue (or decellularized), and sticking it in people's knees and other ligament sites in the body because it's strong.

Which part is difficult to understand? They use medical and scientific terminology, but otherwise it's pretty straightforward.

It essentially covers the usage of macropod (kangaroo, specifically, of an enumerated variety) tendon and ligaments in a grafting procedure using "undisclosed" materials for compatibility. It then enumerates specific elasticity parameters before giving a description of the problem (background).

Basically, exactly what the topic article summarizes into layman.

Ironically, the whole patent appears to be about the concept (how is that patentable?!). The actual treatment is “known in the art “.

Quote: “The tendon is composed mostly of an extra-cellular collagen matrix, which is non-immunogenic. The tendon may therefore require no denaturing (decellularisation) prior to implantation into a mammal. In some embodiments, the tendon may be subjected to a decellularisation process prior to implantation. In removing the cells from the tendon, the immunogenic antibodies within the cells are also removed, thus rendering the tendon non- immunogenic. Methods of decellularisation of tendon tissue are known in the art. Such methods include…”

Furthermore the patent states that "Methods of decellularisation of tendon tissue are known in the art." which means he either lied in the patent, or it's not "special sauce"
I mean, it starts out by saying that the special sauce usually isn't even needed.
Seems like the special sauce is nothing at all but what seems to be well known prior art:

    [0038] In preparing the xenograft for use, the tendon is surgically 
    dissected and removed from the paratenon (tendon sheath). The tendon is 
    composed mostly of an extra-cellular collagen matrix, which is non-
    immunogenic. The tendon may therefore require no denaturing 
    (decellularisation) prior to implantation into a mammal. In some 
    embodiments, the tendon may be subjected to a decellularisation process 
    prior to implantation. In removing the cells from the tendon, the 
    immunogenic antibodies within the cells are also removed, thus rendering the 
    tendon non- immunogenic. Methods of decellularisation of tendon tissue are 
    known in the art. Such methods include physical, chemical and enzymatic 
    treatments, wherein the cells within the tendon are lysed, leaving an 
    undamaged extracellular matrix having the same physical and biochemical 
    properties as the natural tissue.
This was tried with pig tendons about 20 years ago.

I wonder what has changed.

From a cursory glance, the animal.
Yeah seems like kangaroo tendons are much stronger than pig/cow ones. Per the article.
Seems pretty obvious, considering the way kangaroo legs work. I'm surprised it took people this long to figure this out, though I guess since pigs and cows are eaten as food so much, there's a huge surplus of their tendons, unlike kangaroos'.
Though according to both the article and comments ITT, kangaroo meat isn’t unheard of in Australia so a surplus does exist. Probably not one for a global application of this procedure, but enough for experimentation. Perhaps by the time we perfect this lab-grown tendons may be a superior source, or other animals can be used.
THere are more Kangaroos than people in Australia, and while it is a food source, there is ample surplus.
Another case of this:

> You've heard of the golden rule, haven't you? Whoever has the gold makes the rules.

Patents can in fact work that way in practice. Generally speaking the art of the patent is to describe the technique in as broad a way as possible as to cover any possible way to accomplish anything similar while avoiding as many important details needed to actually accomplish the goal as possible. That way the patent is useless for anyone who wants to solve the problem but very useful for you to go after anyone who manages to figure it out on their own.
That is indeed the current practice, but it is the opposite of the original intent of patent concept. The idea was to grant a temporary monopoly in exchange to revealing the technique — it was supposed to advance technology faster.

The standard was (and AFAIK, still is) that the technique or technology must be revealed in sufficient detail that it can be reproduced "by a skilled practitioner in the field without undue experimentation".

Of course, that was at a time when technological progress was much slower, and less transnational.

yeah, there's a pretty wide gulf between patents in practice and their original intent, alas.
<joke>I wonder, does this also make knees harder and faster?</joke>
As someone with trouble giving up on meat this is a highly hypocritical comment but news like this always gives me an unsettling feeling in my stomach. We are sacrificing the life of an intelligent entity to fix the knee of another. Like I said it is hypocritical and I probably found a way to explain it away if I needed itvmyself and am happy for the people it will help but still, we as a species do have the tendency to put ourselves above others. I feel very conflicited by it.
I'd draw a pretty big distinction between this and regular meat eating; you're not getting a new tendon several times a week.

In this case, it's not even extra animal deaths:

> It was important to Dr Hartnell that no kangaroos were killed expressly for his research, and this has remained his practice throughout his investigations: all of the work has been done only using kangaroos that have either been culled for reasons of population control or harvested for meat.

That is true, I think I agree with this.
TIL kangaroos are harvested for meat
Yeah. Very similar to venison, in both taste (lean and a bit gamey) and reasons for culling; too many in an area and no real predators other than humans.
That sounds ironic as kangaroo’s predators were predated (“culled”) by humans.
We're just going to work our way down the food chain.
Already have, many people personally cull grass periodically.
We even have solar panels.
Same with deer (wolf culling)
not just, but yeah !

Kangaroo meat is super lean and very tasty. needs to be cooked very carefully or it goes very chewy and dry.

Leather as well - kangaroo leather was rather prized in the motorcycle community for being more abrasion-resistant per thickness/weight than cow-hide leather. I think its popularity has somewhat fallen off but I believe it's still the most performant material.
Same for whips as I recall. Niche use cases, but it’s apparently much better than others.
Hmm, I wonder which material properties contribute the most benefit to that application. "Abrasion resistance per weight/thickness" seems like it would be somewhat lower on the scale for whips than it is for motorcycle rider protection.
You can buy the jerky on Amazon last I checked. This amazed me the first time I learned about it but apparently it's pretty mundane in Australia
It's a common ingredient in dog food. If a dog is having some sort of allergic reaction, a vet will often recommend switching to kangaroo food to try to rule out a dietary cause. (I guess because kangaroo allergies are rare in dogs? At least in NA?).
If you're in the US, meat selection tends toward the conservative. People have literally been fired for serving kangaroo: https://time.com/5430454/nebraska-school-cook-fired-kangaroo...

But in some European countries, more bits of the animal are being eaten (beef tongue, e.g.), and more animals are being eaten (e.g. horses). In Switzerland, kangaroo and ostrich became somewhat popular when at the height of the Mad Cow Disease epidemic, people were reluctant to eat beef.

You can definitely get beef tongue in the US.
Yes, I did not mean to imply that you can't. But in my informal surveys of Americans, "Do you eat beef tongue?" is an interesting shibboleth to determine culture of origin of the respondent.

I think I've yet to meet somebody with a Christian Anglo-Saxon background who said they did. People with Hispanic, Jewish, Eastern European, and many continental Western European backgrounds often do. Of course beef tongue is also found in Chinese cuisine.

Thanks for pointing that quote up. Nonetheless I have the feeling it only respond to GP in a very short-sighted term. I do understand medical research should go on but don’t mismatch research process with industrial application, especially when they bring ethical concerns.
I suppose this sort of grafting is a behaviour unseen in the natural world, whereas eating is.

I admit my first thought was "are they going to at least eat the kangaroo?" - like that's any consolation for the animal.

Almost all of medicine (aside from the few natural/herbal remedies that actually work) is unseen in the natural world, I don't think we justify closing all the hospitals and medical clinics on that basis.
I really encourage you to try and give up meat and eggs again! It's not too hard -- just like any other habit to build and continue. And honestly I have the same mindset as you. The sacrifice we make to intelligent creatures for 5 minutes of sensory pleasure (taste/smell) makes no sense.
But they're sooooo tasty! Other animals kill other animals, humans are no different.
Sure I think there is broad agreement with taste argument. However, I think we can agree that humans are on another scale with respect to animal killing. We are way past the survival of the fittest on the plains of the Serengeti here.
We might be, but that's not by choice for many.

I hate factory farming and if we lived in a world with more wilderness and healthier oceans, I think hunting is a fairly humane to operate. For most wild animals they die horrible deaths, the most humane way to go is being taken by an expert marksman or archer during adulthood.

I've seen a fish have it's face mauled off by squid, and much worse. If that fish could've been dispatched by fish spike in seconds as opposed to having it's face mauled off, I think it would've went with the spike.

What would you say to someone who’s only qualm is the animals humane treatment?

I typically only eat chicken but I just don’t see an issue with if the chickens are humanely treated and killed. What else would we do with all the chickens besides eat them? They’d die out if we stopped eating them and it’s not like anyone’s going to put them in a zoo.

The way I see it is we’ve bred these animals as livestock and we’re responsible for them as livestock and that’s okay. It’s how we treat them as livestock that matters. Factory farms are one of many gross byproducts of industrialization that we now have to deal with like fossil fuels.

> They’d die out if we stopped eating them and it’s not like anyone’s going to put them in a zoo.

There are feral chickens in quite a few places. https://en.wikipedia.org/wiki/Feral_chicken

Tahiti's airport has a bunch of them.

I'm not sure I agree that a feral chicken has a better life than a domestic chicken being humanely raised for meat/eggs. The feral chicken probably lives in a state of borderline starvation and is at risk from disease and predators; the domestic chicken gets to walk around in a protected area and has a good supply of nutritious food and water and a place to get inside at night and when the weather is bad.

Sure the big factory chicken farms are something else, but you can buy ethically sourced chickens (or raise them yourself if you have the space) if that bothers you.

I mean, we're getting into Star Trek episode ethical/moral dilemmas; is it better to live in a gilded cage, or be free but at risk of poverty? No right answer to this.
Well, the decision isn't between having feral chickens vs. caging them.

Domesticated chickens are bred into existence. We could just stop doing that if we had ethical problems with it. The consideration doesn't hinge on whether there exists some wild variant of the animal we're breeding.

My note about feral chickens was to contest the stated idea upthread that the species would die out if we stopped intentionally breeding them.
True, my comment was really for them: What's wrong with stopping the breeding of a species, especially one we bred to exploit.
> I typically only eat chicken but I just don’t see an issue with if the chickens are humanely treated and killed.

If that's your only concern, and not environmental destruction, then that's fine - if you're ensuring that the chickens you eat are humanely treated and humanely killed. The best way to do that is to buy from local farms you can visit - otherwise it's just aspirational and in effect identical to someone who doesn't care at all.

> The way I see it is we’ve bred these animals as livestock and we’re responsible for them as livestock and that’s okay.

But we can stop mass producing them. There don't need to be 30 billion of them. Scale is what makes factory farming such a catastrophe (environmentally, ethically, and for our own health).

> What would you say to someone who’s only qualm is the animals humane treatment?

The typical response to this would be a game of Name The Trait.

For example, what would be wrong about farming humans as long as we treat them humanely?

Or more generally, what's true of animals that if made true of humans would make it okay to farm humans? And then when you come up with a symmetry breaker, we apply it to humans and see if you're okay with the reductio. If so, you bite the bullet on a crazy human atrocity, and if not, then it's not the trait that actually matters to you.

That's trivially solved with shared culture. Simply by both being human, we share a level of shared experience that would make me uncomfortable eating you. To a lesser extent, we have a shared experience with our domesticated pets, which is why we find it repugnant to eat them, but unlike with Grandma it's okay to give them the Old Yeller' treatment when need be.

Most edge cases you could come up with are covered by "it wouldn't necessarily be unethical to eat them, but we have a universal taboo because edge cases are so absurd and rare."

You're putting forth multiple traits, btw, but I don't think it's as trivial as you think it is.

One trait seems to be "shared culture" whatever that means. What about humans with cultures we don't share? What about humans with downright alien cultures we can hardly understand nor agree with? What does "shared experience" with a dog mean? What about brain-dead humans that we don't share an experience with?

Another trait seems to be "being a human". What about Santa's elves or any hypothetical sentient being that's not a human? Does any alien race that discovers us have the ethical justification to farm us?

> it wouldn't necessarily be unethical to eat them, but we have a universal taboo because edge cases are so absurd and rare.

Would it be okay to farm or enslave humans if we simply didn't have that taboo? Or in a hypothetical world where it wasn't taboo: would it be okay then?

These aren't edge cases btw, these are reductios that test for position's consistency and dispel the sort of "I'll know it when I see it" hand-waving we like to do.

Any coherent position has a coherent answer to hypotheticals.

There is a trivial answer that does nip it easily in the bud: we agree to value sentience thus we stop farming sentient beings whether they're human, cows, or Santa's elves.

Finally, I was just offering a potential response to your question. HN is a poor place for this kind of discussion, but I hope you at least see that there is conversational meat on the bone, pun not intended.

The less "like us" they are, they more justified we are in killing them. "Like us" is tied around shared culture and experience. If you asked me to choose between saving the life of an elf and the life of a human being, I'd choose the human damn near every time (barring cases where the human deserves death regardless of the dilemma).

"Shared experience" in this case is a basic history of doing stuff together, or in a sympathetically similar way. Dogs have been shaped to serve side-by-side with humans as companions, sharing in our experiences. So eating them is wrong. There are no humans that are less like us than than the animals we eat. Brain-dead humans are an example of just following taboo: We don't kill and eat other humans, because of the whole "we are more alike than we are different" thing, and incidentally extend the same courtesy to things that take complex explanations for not being us.

If we ran into other conscious, sapient species, we'd probably be hesitant about killing them due to the shared experience of sentience making them a lot more like us than a cow. But on the other hand, killing an alien would be a hell of a lot more permissible than killing a human.

And I apply the same kind of logic to people. My friends and family are significantly more valuable than random strangers. In a trolley scenario with one of my friends on one track and 3 strangers on another, I'd save my friend, every time, and I wouldn't trust anybody who would answer otherwise.

There's a philosophical problem you run into here. A man who has no hair is obviously bald, and so is a man with exactly 1 hair. But how many hairs does it take for this man to suddenly no longer be bald? Not only is there no "real" answer; the practical answers will vary in subjective and inconsistent ways from person to person. It's an abstract and largely subjective value judgement. And I think the same is true here. There's no single binary value where something goes from A to B.

Take mosquitoes. Even in areas where mosquitoes rarely if ever carry diseases, people are perfectly cool with widescale genocide. Why? Because half of those animals can, on occasion, give us a little itchy that's mildly inconvenient for a few moments. Roaches are another example. In their case, their life itself is often worth less than our mild annoyance or discomfort at seeing them. And so on. In practice, most people are perfectly fine with killing the overwhelming majority of species of animals.

And so too here. I simply do not see any problem with killing a e.g. chicken for food. Oddly enough I have a strong suspicion that the more one is around animals, the more this becomes true. Which is paradoxical, because contrary to what you might think, even chickens can be awesome little affectionate critters. It's probably because you see the cycle of life itself more regularly. Foxes are cute, clever, and awesome critters - until one makes its way into your chicken coop, kills every hen, and takes exactly 1 away. At the same time, that's just the nature of life. It's all as natural and normal as the fact that you and I too will be wormfood soon enough.

Using animal behavior as a blueprint to justify human behavior won't end well.
Other animals also practice cannibalism and so do humans. Killing other animals for food is not the same as killing humans, but also we humans differ from other carnivores and omnivores.

I find meat also very tasty and eat meat. There are several ways to reduce impacts though: Eating less will most likely also have a health benefit. Game doesn’t suffer it’s whole life but only when it gets hunted.

Other animals also commit rape for pleasure, but we don't use that as a moral guideline for human behavior.
It's possible to get adequate nutrition with a vegan diet but it's a lot of effort (at least until it becomes habit) and for children it's particularly risky. People are omnivores and meat provides a lot of the nutrition we need. I don't think anyone should feel guilty about eating meat per-se, though the conditions and treatment of animals in some farming operations are valid concerns.
> the conditions and treatment of animals in some farming operations are valid concerns

Anyone who has the room for a chest freezer in their garage and can afford it can go to a local farm and buy a whole (or half or quarter) cow, lamb, or pig and have them slaughtered and deep frozen.

Depending on their locality, there are usually plenty of such farms that usually treat their animals much better than the farms supplying super markets. Makes it much easier to inspect their farm in person too.

I understand that paradox. The way I rationalize when it comes to food is that we wouldn't feel bad for a lion eating a gazelle... well we might but it would be required as lions eat that food. We're somewhere on that spectrum of omnivores who eat meat and that means eating animals.
The lion doesn't really have our capacity to reason (to the same extent) or come up with alternatives. Lions can't make an Impossible Burger; we can, which changes the ethical calculus a bit.
That's because the lion doesn't have an abundance of resources that allow it care about "ethical calculus." It simply eats, mates, socializes, and sleeps; and it is satisfied with this arrangement -- never feeling the need for "more."

In my opinion, thought that verges beyond: "how to acquire food," "how to acquire mate," "how to acquire friend," and "how to acquire sleep" is "too much," and a neuroses. Or maybe all of our actions are predicated on fulfilling these base needs? And that our civilization has created an environment where these needs can no longer be simply attained, so we come up with ever more complex ways to attempt attaining them.

One can also make the distinction that those needs are also simply just "feel good" and "don't feel bad." For a lion, the aforementioned things are enough to "feel good." But for us people, the simple pleasures have become unattainable in any sustainable sense. So we once again try to find something to make us feel good. For the GP, that might be practicing vegetarianism; for the readers of Hacker News, it might be stuffing their minds full of information of only temporary utility.

And for what? So we can feel good, and escape the bad. "Ethical calculus" is no different. It's simply a rationalization of our base needs. Though I wish the simpler pleasures were more readily available... I'm getting awfully tired of working harder and smarter to find outlets!

> we wouldn't feel bad for a lion eating a gazelle

Most people probably do feel bad. Presumably you'd also feel bad if a lion attacked and ate a human even though it was just doing what you purport to be "required".

Where it goes south is when people cherry pick the behavior of animals to justify their own actions.

Say you're driving down the road and get into an accident. A choice in front of you is that you either hit a squirrel or a child.

Would you feel better or worse?

Chimps kill and eat monkeys and even other chimps. Not sure what I should rationalize through that behavior.
Maybe that we should incarcerate chimps?
I don't I always find it crazy that society has drawn these weird lines where if you want some chicken tenders you can slaughter a billion and treat them terrible but if you want to push the limits of human knowledge you need 6 levels of oversight.
It's a phenomenal demonstration of the human brain when a video of a guy being mean to a dog will win the outrage of Twitter while 23,000,000+ land animals are slaughtered per day for food in the US.

What we seem to care about as a civilization is like a narrowly focused laser: we can only wrap our heads around the things small enough to fit in the tiny spotlight. Anything bigger and we just kinda take it for granted.

It's not that weird. We bred dogs for millennia to read and express human-recognizable emotional responses. They are sympathetic by design. In contrast, We bred most everything else to be delicious. A more fun one is to look at people's responses to guinea pigs, which were bred for eating but now are seen as pets.
That may be a satisfying explanation at first pass, but it breaks down quickly under scrutiny, I think.

We can recognize the emotional state of pigs and cows, probably more than even we can with cats. Certainly more than we can with rodents and other pets.

I also think most people wouldn't accept a video of someone abusing a cow, pig, or even a chicken. Let's just replace dog with piglet in my comment if that helps track the point.

I'd wager most people wouldn't find footage inside a slaughterhouse or factory farm very palatable. But this happens by the hundreds of millions daily.

Cats may not emote in human terms as well as dogs, but they are unusually good among the animal kingdom at reading human emotional expression.
>we as a species do have the tendency to put ourselves above others

I mean, all species do this. Antelope don't lay down to be eaten by lions because it is good for the lion.

It is funny that you feel like this is wrong while eating meat. I also eat meat and I would say it is morally much worse to kill a pig because I like the taste of the food and killing a kangaroo to provide significant quality of life improvement through increased mobility to those with severely damaged knees. I have zero issue with this being used until a better solution without killing a kangaroo could be developed.

Kangaroos don’t have many natural predators anymore. Even if you don’t harvest them for meat, you’d have to cull them to prevent them overpopulating and destroying their environment.

The article mentions that the kangaroos harvested for meat are sufficient to meet the current worldwide needs for ACL surgeries.

Sometimes killing animals is the ethical thing to do. Reality is complex.

What makes the kangaroo problem even worse is they're grazers, and maybe it's just a former British colony thing, but people like to plant grass.
Grasses plant themselves and taken over from much of the native vegetation. We do like to cut down trees and clear bushland though. Every new cow paddock is also a kangaroo paddock.
> you’d have to cull them to prevent them overpopulating and destroying their environment.

We don't do this for cats, why should we have to do it for kangaroos? Trap Neuter Release exists. There have been struggles with implementing it, but it seems largely to do with lack of awareness and funding.

AFAICT, no one around here culls or traps cats, but we don't have a cat overpopulation problem. OTOH, even with hunting seasons, we definitely have a deer population problem, and the rabbits have been going insane this year for some reason.

Perhaps it's just a case of different strategies for different regions.

New Zealand apparently does. Never been there, seems lovely

(edit: this opening graf is too good not to share)

"Animal welfare protestors at a hunting contest in rural New Zealand have faced off against a group of child attendees, some clutching dead feral cats, who repeatedly chanted the word “meat” at demonstrators."

https://www.theguardian.com/world/2023/jun/28/chaos-at-new-z...

Cats are predators, that’s very different from say deer or kangaroo populations, which tend to overboom and then starve after they strip the environment of the plants they eat.
We do cull cats. With numbers in the millions killing billions of native animals per year and already contributing to many extinctions, nothing is going to work except for science fiction bioweapons. Discussion and research is more around how to efficiently kill as many feral cats as possible without killing native animals or pets.

https://www.abc.net.au/news/2021-02-08/federal-inquiry-propo...

NSW is culling them because of overpopulation. At least that's what the kangaroo scrotum keychain the gift shop was selling said.
kangaroo scrotum ? where I live they sell souvenirs allegedly made of camel scrotum. it seems the scrotum trick works seemlessly on all tourists whatever origin they have :)
If it helps to put your mind at ease, in some parts of Australia Kangaroos are a pest. They are culled in agricultural areas and this treatment prevents some of the animal from going to waste. They're also often roadkill as they chase headlights at night.

Companies pay hunters around $1-$2 per kg for the kangaroo meat. An adult kangaroo can be upwards of 60kg (130lb). The meat is often used for dog food, but is extremely lean but a bit gamey tasting I've been told.

So, hopefully this treatment doesn't cause additional death of the roos, but helps to make their deaths less wasteful.

It’s possibly the Disney effect on the culture affecting your subconscious.

If we had happy cows as cartoon characters we might not eat as much beef.

A film that explores a similar theme is The Island (2005) - recommended!
I am not conflicted in the slightest. It's a "dog eat dog" world where every species put's its survival over others.

I hunt and slaughter animals. While I do fully understand and appreciate the sanctity of all forms of life, I also understand that my actions are part of the natural order of the universe.

If they’re using decellularization to prevent rejection, does the tissue have to be … freshly harvested (i.e. in a medical setting) ?

Or would the offcuts from abattoir-killed roos be of sufficient quality ?

It seems tu be sufficient. Although maybe the abattoir have to really follow sanitary rules for once, that'll cut into the profits.
Just in time for the WWC where there's recent news articles about why the women's game has so many ACL type injuries.
This is very cyberpunk.
Kangaroo knees? Where do I sign up?

And if you could replace my spine too while you're at it, that'd be great.

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One assumption this skips over is that it's okay to put athletes on the field with ligaments 6 times stronger than human baseline.

Of course this is a phenomenal treatment assuming it works as planned, but isn't there a performance enhancement angle that needs to be considered for it's inclusion in professional sports?

The Enhanced Games will be stoked for this.
Like the old SNL sketch: The All-Drug Olympics!
I'm okay with dealing with this problem when it comes, I definitely do not consider it a good reason to slow down medical progress. I'd rather sport adapts to medical progress, not the other way around!
The inverse of your position would mean that athletes would be forbidden from ever having surgery, including for sports injuries. Taken to an extreme, athletes should be forbidden from having any kind of medicine: vaccines, bandages, antibiotic ointments for cuts, etc.
I don't think so, the tendons make the knee potentially more stable, the performance so comes from the muscles. And it requires surgery, usually that kind of surgery is hard on the body, and requires extensive physio therapy and training afterwards.

So, the kangaroo tendons are potentially better than traditional implants, the question you pose so is whether or not they are better than the original, human ones. And I somehow doubt that, but I am just a semi-engineer with a ruptured, but still working, knee and not a physician.

That's my thinking too, but I am left wondering if athletes with this implant will be able to pull riskier corners knowing that their knees are unlikely to give this time.

I look forward to finding out either way

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This surgery has a very long recovery time. The ligaments are just part of the story, the bigger risk is the cartilage in the joint - if it tears, good luck, we have nothing to fix it. Expensive stem cell therapy maybe kind of works. CPM (continuous passive motion) sort of works over years, and then there are the cripple-you-for-life titanium joint replacements surgeries.

In short, this is far, far from being a concern, as cartilage will fail even if the ligament can take it. Similar issue as steroid-user muscle growth outpacing tendonds.

Medicine can't repair anything. I will repeat this for the 1000th time, if you think we have tech realize that we - can't fix an artery, re-attach a nail to the nail bed, fix some crystals on teeth (enamel), regrow hair, etc, let alone re-attach a nerve (though we do bypasses now). Basically, people way overestimate the reality of what they can do when they hear 3d organ printing myths.

Recovery is indeed long: my surgeon, who specializes in this stuff and treats professional soccer players as well, talkes about a year until a potential return to normal training and 6 months until being able to run in non-straight lines... Well, for now it seems I can get away without suregery (we'll see what skiing this winter has to say), but it is nothing an athlete would do, loosing a year of training will not be worth it, on fact it can and does mean the end of a career.
I wonder if human muscles can pull those stronger tendons as they should to walk and run normally. Probably the surgeons can weaken them a bit before the implant.
I for one welcome tendons of a kangaroo, teeth of a beaver, arms of a gorilla.

viva la meta-human!

It becomes a problem if your post-college Tommy John requires you to get a kangaroo tendon to be competitive in MLB. Not sure how you solve that problem in a fair and repeatable way though.
Across species, tendon strength is strongly correlated with modulus (normalized stiffness). Greater stiffness has the risk of reducing range of motion. When a graft is used it is intended/hoped that the graft will remodel over time to become more similar to the original tendon's properties, which match what the entire organ system needs to function properly. Nor does a stronger graft mean that the connection between the graft and the bone will be 6× stronger. 6× stronger might also be optimistic; prior work suggests more like 2× stronger and stiffer.

https://pubmed.ncbi.nlm.nih.gov/23599401/

> One assumption this skips over is that it's okay to put athletes on the field with ligaments 6 times stronger than human baseline.

I would love this, if only so I have less chance of going through a fix again. I received a patellagraph to fix a torn ACL, and the rehab is what makes it such a PITA. It took 9ish months to be cleared for sports again, and I didn't feel confident in my knee until 18 months or so.

I gather that kangaroo "leather" is also quite resilient.
What if the "bionic man" from SciFi is not robots and nanomaterials but actually just us borrowing things from nature that happen to work better than the human version
A menagerie of animal-part patchwork humans sounds like a great time!
Is it possible to farm Kangaroos for this purpose? Perhaps its brutal to suggest, but I imagine hunting wild Kangaroos is not what we want here, as their numbers are already in decline, IIRC.

Can the rest of a Kangaroo be used in some productive way? I'd honestly feel ethically bad that we are killing Kangaroos just for their muscle tendon in certain areas

The bloody things breed like rabbits... you dont need to farm them.
I was under the impression that Kangaroos were an overpopulated nuisance.
> Can the rest of a Kangaroo be used in some productive way? I'd honestly feel ethically bad that we are killing Kangaroos just for their muscle tendon in certain areas

From the article:

> It was important to Dr Hartnell that no kangaroos were killed expressly for his research, and this has remained his practice throughout his investigations: all of the work has been done only using kangaroos that have either been culled for reasons of population control or harvested for meat.

Kangaroo populations are fine; culling is done to keep them from overpopulating. Similar to deer in the US.

https://www.theguardian.com/environment/2019/jul/12/koala-ka...

Total numbers are anything but in decline. Unfortunately though, we seem incapable of correctly managing the required culling and puts pressure on the more endangered species rather than the intended ones. And there are disagreements about the methodology used to count the population numbers and thus the number that need culling.

The meat is available for human consumption, but often isn't stocked due to consumer boycotts. So most of the meat from culling ends up as dogfood or wasted. Maybe this will change with Australians embracing traditional culture more, but for now 'eating the national animal' horrifies many who will stick to their non-native farm animals.

The leather is great, used for top-tier foot ware and sporting equipment like footballs. But this is being replaced with synthetic materials, driven by consumer ethical concerns again. Most of those concerns seem driven by problems in the culling industry, and the horrific news articles it generates fairly regularly.

Bone as usual goes to fertilizer.

>"undisclosed" materials for compatibility"

Should not it invalidate the patent?

Should genetic engineering on humans ever become feasible to the point where you can make large changes to the body plan, I wonder if reverting bipedalism would be easier than fixing all of the problems it causes (such as, I assume, knees, due to taking all of the load on half of the limb joints, but, also, back problems, etc). With human computer interaction technology advancements, we may eventually move beyond needing hands at all, anyway.
When predictable genetic engineering of animals will become possible, there will be no difficulty in growing both two hands and four legs, like in the mythical Centaurs.
Not necessarily. That is like saying “when predictable engineering of bridges becomes possible, there will be no difficulty in creating a floating-in-air bridge”. Engineering challenges still exist. My point is whether going to a more standard body plan is an easier engineering problem than fixing the design flaws in the nonstandard human one.
Your counterexample is not valid. There are reasons why a "floating bridge" would not be easy to make, but the fact that all the vertebrates with jaws that exist today have no more than four paired limbs is just a historical accident and only small changes in their body plan would be necessary to make one with six paired limbs or even with much more.

In some vertebrates, i.e. amphibians, it is very easy to generate supernumerary limbs without any genetic engineering, but just by manipulating the embryos.

Due to defects in the development of the embryo, birds or mammals and even humans are sometimes born with polymelia, i.e. with extra legs, and some of them succeed to have a relatively normal life.

https://en.wikipedia.org/wiki/Polymelia

The purpose of predictable genetic engineering would be to ensure the development of a body precisely into a form optimized for a certain purpose. Obtaining random monstrous forms is easy even today, by using various mutagen agents and/or embryo manipulations.

The problem isn’t generating something with a certain body plan, I agree that is easy. The problem is achieving a design without common or significant mechanical problems over the lifespan of the organism. Can we assert that, in your example, animals with extra limbs don’t have problems on par with the back or knee problems of bipeds? I don’t think we can?
It is very unlikely that predictable genetic engineering for animals will become possible earlier than twenty years from now and a time between 50 years and 100 years from now seems most likely.

We are still very far from completely understanding how a single nucleated (eukaryotic) cell works. After understanding a cell we should first be able to completely understand simpler multi-cellular living beings like fungi and plants. The animals are the most complex and there is no doubt that they will be the last for which it will become possible to change some genes and then predict with certainty what kind of animal will develop from such a modified cell.

In any case, when that will happen it will be possible to design the body of an animal, within certain constraints, like we design now any complex machine. Bad designs will always remain possible, but good designs should easy avoid mechanical problems in the legs. By that time the simulation possibilities should be much better than today.

This comment is peak HN. Like it's so absurd that it feels like it must be satire.
Bipedalism doesn't cause problems. Sitting on your ass all day and then occasionally doing stuff that overstresses your now-weakened joints causes problems.
You only get knee and back problems when you're old, which is because the body just stops repairing itself as effectively as it does when you're young.

It's going to be far easier to re-enable the ability to self-repair our bodies as we do in youth than to completely change the function of two of our limbs.

Completely false. Lots of people in their 20s have knee and back problems. Torn ACLs are common in athletes and people who participate in sports. I had a coworker a few years ago who had his ACL replaced; he was in his mid-to-late 20s.
Please re-read and reconsider the context of my post. This reddit-tier "must seek to contradict and attack others" behavior doesn't do anyone any good.
Ok, fine. I re-read it, and it says: "You only get knee and back problems when you're old, which is because..."

Your statement is blatantly false. It says, literally, you only get knee and back problems when you're old. This is wrong, and stupid.

Why are you arguing this?

Don’t know why people have objections to this, we already use bovine and pig valves in hearts, saves lives, improves health. I am comforted by the fact that if I ever need to rebuild a knee someday in the future, kangaroo tendons may be an option, so I can stay off the bench and stay on the basketball court.
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Bold of you to assume someone hasn't already created that thread/meme.
Doesn't this increase the chance of novel diseases when they cross from kangaroo to human?
The ligament is denatured/ all cells removed which just leaves a scaffolding for the natural tendon to populate
Question: Would my new kangaroo enhanced legs disqualify me from the Tour de France?
One has to be rather careful about the wordings of such announcement. I keep thinking "Dr. Nick want's to replace bits of my mom body with kangaroo parts.... I wonder how my dad feels about that?".
How would this not result in kangaroo harvesting farms/extinction?
hahaha if you can figure out how to farm Kangaroos, let us Aussies know please!
Cool but I’d rather have fully automated robotic legs that can let me jump like 30ft and sustain falls from 100+ ft.
I need one, I just ruptured my ACL.
I just happened to suffer an ACL tear 5 weeks ago. A week later I had ligamys implanted to great success. Four weeks post-op not only can I walk, I can also cycle. I am surprised this is not mentioned in the article. It is true ligamys only works if done soon after the tear but it would seem to my naive few that it would cover most cases.
That sounds very promising. Too late in my case I would have needed it 15 years ago.