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German scientists creating a high-tech artificial hip

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May 7, 2012

Fraunhofer's experimental new artificial hip (right)

Fraunhofer's experimental new artificial hip (right)

While modern artificial hips are made of a number of high-tech materials, metal is still often the material of choice for younger, more active patients. This is due mainly to the fact that it’s so robust. Unfortunately, however, difficulties can arise in the metal ball-and-socket interface – where the artificial head of the femur meets the artificial socket of the pelvis – if things aren't perfectly aligned. In particular, the metal surfaces can wear against one another, decreasing the longevity of the implant and potentially causing health problems in the patient. Now, researchers from Germany’s Fraunhofer Institute for Manufacturing Engineering and Automation are developing a new type of heavy-duty artificial hip, that contains no metal at all.

Both parts of the system take the form of thin shells, that are attached over top of the existing bone surfaces.

The socket implant (which is attached to the pelvis) is made of carbon fiber-reinforced PEEK, a biocompatible, high-strength, wear-resistant polymer composite. The femoral head is made from ceramic, and incorporates a coating of the natural bone component hydroxylapatite, where it joins the patient’s original femur. This attracts stem cells from the adjacent bone marrow, helping the bone to grow into the implant.

Along with the hydroxylapatite on the femoral head, the implants both feature a scaffold-like material containing tiny pins, on the surfaces where they join the bone. This allows them to be pressed and tapped securely into place, using a specialized disposable tool that is attached to standard surgical instruments. They can also be detached and repositioned as needed, while being implanted.

No bone cement is required – bone cement can sometimes crack and fail, causing the implant to come loose. Additionally, because it’s just a shell, the femoral head doesn’t require the traditional long attachment stem that extends down into the inside of the femur. This means that less of the patient’s own bone material needs to be removed.

Because both of the implants are reasonably flexible, more like bone and less like steel, they have been shown to transfer less stress into the surrounding bone than steel systems. Their performance has been tested using a robotic rig that simulates activities such as walking and climbing stairs, while the bone attachment scaffold has been demonstrated on cadavers.

Fraunhofer is developing the hip implants as part of an international team of organizations, that are taking part in the ENDURE (Enhanced Durability Resurfacing Endoprosthesis) project.

Source: Fraunhofer

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
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7 Comments

Being in materials science, and not a hip recipient, I've still seen lots of joint replacement schemes, from a distance. This is certainly one of the more promising concepts. I've always been appalled at how much the femur is changed during a hip replacement procedure. this looks a lot less scary.

joez
8th May, 2012 @ 10:38 am PDT

you know its a good article when there is a lack of comments.. lol

Michael Mantion
8th May, 2012 @ 10:47 am PDT

I'd like to see some new inventions for knees. I have a knee without a kneecap, and most knee replacements need the kneecap to work correctly.

Kelly Priest
8th May, 2012 @ 11:13 am PDT

Hear Hear,with an aging population suffering from the effects of thier sporting/occupational and accident suffering pasts,we need better replacement technology.

gragraposker
9th May, 2012 @ 02:52 am PDT

I am assuming that the hip replacement was necessitated due either to wear and tear or accident. I wonder how well the new bone growth would stand up if the original one did wear out or break. In any case this is definitely a very promising research and development.

pmshah
23rd May, 2012 @ 12:49 am PDT

Being a receipiant of recalled MOM hip resurfacing and not wanting a conventional hip replacment this sounds like a tarific option and I would be glad to try one. Once you cut that femur there is no going back

Stuart Quigley
4th October, 2012 @ 02:36 am PDT

Great idea...would like more information

And testing before I would want it...

Becky Hall
27th June, 2014 @ 05:33 am PDT
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