World's First Biodegradable Joint Implant Grows New Joints

cylonlover writes "Joint implants should always be made of materials like titanium, so they can last the lifetime of the patient ... right? Well, not according to researchers at Finland's Tampere University of Technology. They've developed a product known as RegJoint, which is reportedly the world's first biodegradable joint implant. Unlike permanent implants, it allows the patient's bone ends to remain intact, and it creates a new joint out of their own tissue."

Comments

The details

[arnoldo.j.nunez]

So I'll save anyone wanting to read the article for scientific details the trouble: they don't even mention the material used!

So I searched around and found this. http://www.scaffdex.com/sites/default/files/RegJoint_IfU_rev_0_1.pdf

I thought I knew polymers, but my biochemistry is a bit weak. 96L/4D poly-L/D-lactide copolymer fiber. Seems to be porous, is that the key to making a bodily joint?

Apparently it loses it strength as quickly as within 15 to 24 weeks and then completely loses its strength within a few years. Meanwhile, your body is allowed a framework to develop around after physical trauma.

Re:The details

[dbIII]

I went to a presentation about materials in joints around 1998 and one very interesting point was raised by a Japanese researcher.
Hard joints grind your bone ends into bits. Hundreds of millions of little bits. It does things to the immune system (which attacks solid bone in such situations after being fooled by lots of tiny bits of bone) and creates extra wear on any cartlidge, tendons or anything else in the vicinity. We are bags of mostly water so that stuff doesn't stay put. The life of the joint depends on both it's structure and the damage to the surrounds, which can be measured in inches/centimetres so the replacement joint has to be a lot larger.
At the time making the surface of a joint very porous and relatively soft was the way things were going since it's now expected that people with artificial joints will live for more than a decade after the joint is put in place. The old style of using very hard materials in direct contact with bone doesn't last long enough.

Re:The details

[muon-catalyzed]

I read TFA and they claim the damaged joint structure regenerates by itself, the copolymer is a scaffold that triggers stem cells to grow a brand new joint structure completely replacing the said copolymer with the body's own tissue after a while. In other words, that would be the holy grail of joint repair, of course, only if the stuff is really working as advertised.

Re:The details

[Ihmhi]

I'd rather have some kind of hybrid, like a titanium kneecap with this polymer connecting the end joints.

Dammit, if I'm going to get body parts replaced when I'm older I want to be able to knee someone in the head and have it sound like an aluminum bat hitting a soft ball. *tink!*

Re:Porn Use?

[cosm]

If your Penis has joints in it, you've got more serious concerns.

Like which axial direction to articulate in? One direction could lead to a new baby while the other will have you questioning the bars you've been going to.

Re:Porn Use?

[jlar]

"If your Penis has joints in it, you've got more serious concerns."

Like maybe having too many genes in common with chimpanzees or gorillas?

http://en.wikipedia.org/wiki/Baculum

Re:Why aren't we already using bone made bones?

[ByOhTek]

Really, it is only embryonic stem cells that ever have an issue here with banning/restriction. That isn't nearly as much of a setback now as it was 3-4 years ago. Even if you ignore the ethical issues, the setback is probably worth it - it has accelerated the development of techniques for "undifferentiated" adult stem cells so they can create more cell lineages than they could have naturally. Why is this a big deal? What kind of rejection issues will you have to face when your new transplant comes from another person's tissue? Now, what if it comes from your own? That's the advantage.

Re:Why aren't we already using bone made bones?

[sheepe2004]

As I understand it the problem is in the other stuff that surround the cells (disclaimer: I only did one very short course on tissue engineering).

Basically it's a chicken and egg problem: the stem cells need a good structure to grow in but the structure needs to be created by the cells. A solution is to create an implant which allows the cells to grow within it and then gracefully degrades as it is replaced by the natural bone/collagen etc. which seems to be what these guys have done.

It's a difficult (materials science) problem because there are a lot of requirements. For example it needs to be as tough as bone but break down after a reasonable amount of time. It needs to be non-toxic (before and after breaking down). It of course needs to be cheap(ish) and reasonably easy to mass produce. Anyway there's much more information here.

Re:Implants are not titanium

[pnewhook]

Joint implants are not titanium. No, no no. That's a myth that won't die.

No, sorry it is you that is mistaken. Medical grade titanium (Ti6Al4V Grade 5) is widely used for joint implants because it is biocompatible and MR safe. ASTM-75 is only classified as MR Conditional at best so its effect on MR image quality and localized tissue heating has not yet been fully established.

Just do a search on Titanium joint implant and you'll see they do in fact exist and are quite popular