Featured Research

from universities, journals, and other organizations

Hip implant for long-term use

Date:
May 4, 2012
Source:
Fraunhofer-Gesellschaft
Summary:
Hip replacement is one of the most frequent operations carried out in Germany. Each year, doctors implant some 200,000 artificial hip joints. Often the artificial hips need to be replaced just ten years later. In the future, a new implant currently being developed using high technology materials could help prevent premature revision surgeries.

As the interface between the cell and its environment, the cell membrane, which consists of fats and proteins, fulfils a variety of vital functions. Scientists at the Max Planck Institute of Biochemistry in Martinsried near Munich have performed the first comprehensive analysis of the molecular structure of this boundary layer, and revealed precisely how it is organised. In yeast cells, the entire membrane is made up of independent domains, each containing just one or a few protein types. If a protein is relocated to an inappropriate domain, it may even fail to function. The study shows that the membrane is a kind of patchwork quilt and should help scientists to gain a better understanding of basic cellular processes.
Credit: Image courtesy of Fraunhofer-Gesellschaft

Hip replacement is one of the most frequent operations carried out in Germany. Each year, doctors implant some 200,000 artificial hip joints. Often the artificial hips need to be replaced just ten years later. In the future, a new implant currently being developed using high technology materials could help prevent premature revision surgeries.

Thanks to artificial hips, people with irreparable damage to the joint have been able to lead active, pain-free lives for the past 50 years. Still, some hip replacements do not function completely as intended, and metal-on-metal implants in particular, demand accurate positioning in surgery and implants positioned non optimally are often susceptible to premature failure notably in small female patients. Physicians are even calling for a prohibition on the use of artificial joints made of cobalt-chromium alloys in which the joint's metal ball rubs against its metal socket whenever the wearer walks. Poorly designed or positioned metal on metal implants can lead to higher wear rates and this releases elevated cobalt-chromium ion levels that spread out through the blood and lymph, potentially damaging organs and triggering inflammation. Metal ions are also suspected carcinogens. Because these hip replacements are so robust, however, to date they have often been implanted in young, active patients.

A metal-free composite

Researchers at the Fraunhofer Institute for Manufacturing Engineering and Automation IPA in Stuttgart, partnering in an international team on an EC-funded project entitled "ENDURE" (Enhanced Durability Resurfacing Endoprosthesis), have now developed a new kind of hip implant that, unlike the conventional counterpart implants on the market today, provide a metal-free solution and bone-like elasticity. This is the result of a metal-free, high-tech composite: The hip socket is made of carbon fibre-reinforced PEEK -- a high-strength, wear resistant, biocompatible polymer composite. For the femoral head, ceramic was used. In addition to this, a hydroxylapatite coating at the interface to the bone helps ensure that the bone tissue will fuse thoroughly with the surface structure of the implant. "The cobalt-chromium implants in use to date are very rigid, and the load transfer to the bone is non-optimal leading to potential adverse bone adaptation. Thanks to the new combination of materials, the transmission of force through the PEEK hip socket to the pelvic bone is modeled on natural conditions. And there are no metal ions released," notes IPA engineer Jasmin Hipp. The researcher and her team were able to confirm the good wear resistance in initial tests of the new hip replacement using a robot that simulated various series of movements such as walking or climbing and descending stairs. The experiments used a prototype of the implant.

Tiny pins protect bone tissue

The ENDURE implants follow the bone-preserving principle of hip resurfacing: they are thin-walled shells which replace the bearing surface of the joint articulation alone, instead of employing large metal stems for support, which require a substantial volume of bone to be removed. Researchers have also redesigned the way the prosthesis is mechanically attached to the bone. Without cement, and using a press-fit and an integral scaffold-type structure on the surfaces of the implant that contact the bone, the hemispherical ball and socket are tapped onto the prepared femoral head and into the acetabulum -- the natural, concave surface of the pelvis -- and anchored in place.

To ensure the best possible positioning of the artificial hip, the researchers at IPA have developed a size-scalable tool that attaches the implant to standard surgical instruments, enabling implantation, re-alignment and removal. The tool can be discarded after a single use -- like a disposable surgical glove. The challenge is to attach instruments to the very thin-walled cup implant, with sufficient strength for implant repositioning. The instrument features a smart collet pin combination allowing strong, quick, single-position attachment and detachment by the surgeon. The scientists have already submitted a patent application for the tool. A team of physicians at the University of Newcastle have demonstrated in operations performed on cadavers, the new hip can be set in place and, if necessary, removed without any difficulties. Meanwhile, the preclinical studies have been completed, and final development work is being planned to allow clinical studies to commence. Partners in the EU-funded project are Aurora Medical, Medicoat, Hunt Developments, Ala Ortho, CeramTec, Invibio, Biomatech and the Universities of Gothenburg and Southampton.


Story Source:

The above story is based on materials provided by Fraunhofer-Gesellschaft. Note: Materials may be edited for content and length.


Cite This Page:

Fraunhofer-Gesellschaft. "Hip implant for long-term use." ScienceDaily. ScienceDaily, 4 May 2012. <www.sciencedaily.com/releases/2012/05/120504135811.htm>.
Fraunhofer-Gesellschaft. (2012, May 4). Hip implant for long-term use. ScienceDaily. Retrieved August 23, 2014 from www.sciencedaily.com/releases/2012/05/120504135811.htm
Fraunhofer-Gesellschaft. "Hip implant for long-term use." ScienceDaily. www.sciencedaily.com/releases/2012/05/120504135811.htm (accessed August 23, 2014).

Share This




More Health & Medicine News

Saturday, August 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Newsy (Aug. 21, 2014) An experimental drug used to treat Marburg virus in rhesus monkeys could give new insight into a similar treatment for Ebola. Video provided by Newsy
Powered by NewsLook.com
Two US Ebola Patients Leave Hospital Free of the Disease

Two US Ebola Patients Leave Hospital Free of the Disease

AFP (Aug. 21, 2014) Two American missionaries who were sickened with Ebola while working in Liberia and were treated with an experimental drug are doing better and have left the hospital, doctors say on August 21, 2014. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
Cadavers, a Teen, and a Medical School Dream

Cadavers, a Teen, and a Medical School Dream

AP (Aug. 21, 2014) Contains graphic content. He's only 17. But Johntrell Bowles has wanted to be a doctor from a young age, despite the odds against him. He was recently the youngest participant in a cadaver program at the Indiana University NW medical school. (Aug. 21) Video provided by AP
Powered by NewsLook.com
American Ebola Patients Released: What Cured Them?

American Ebola Patients Released: What Cured Them?

Newsy (Aug. 21, 2014) It's unclear whether the American Ebola patients' recoveries can be attributed to an experimental drug or early detection and good medical care. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins