Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Safely fixed hip prostheses

27.01.2009
Artificial hip joints are firmly anchored to the patient’s damaged bone by screws. But which parts of the bone will safely hold the screws in place? A simulation model is to calculate the strength of the bone from computer tomography images.

Hip prostheses do not hold forever. If an implant comes loose, the doctors have to replace it. Most patients need this second operation after about 15 years. By then, the first prosthesis has often worn down the pelvic bone in several places.

Moreover, the bone density, and thus also its strength, changes with increasing age. Medics therefore have to work out where best to place the screws that connect the artificial joint to the bone, and what shape the hip prosthesis needs to be in order to fit the surrounding bones as well as possible.

At present, doctors examine patients using computer tomography (CT), and determine the rough density of the bones from the images. On the basis of various assumptions, they then calculate how strong the bones are in different places. The problem is that, although there are various theories on which the simulations can be based, the results often deviate significantly from reality. The consistency of the damaged bones is usually different from what the simulation leads to believe.

This is set to be changed by researchers at the Fraunhofer Institute for Machine Tools and Forming Technology IWU in Dresden and their colleagues at the biomechanics laboratory of the University of Leipzig. They are developing a model with which doctors can reliably and realistically calculate the density and elasticity of the bone from the CT scanner images. To this end, the researchers are transferring methods usually used for component testing to human hip bones, which involve inducing oscillations in the bone. This type of examination cannot be carried out on the patient. The bone has to be clamped into an apparatus. “The nature of the oscillations enables us to deduce local properties of the bone – such as its density and elasticity,” explains IWU group manager Martin Quickert.

The researchers compare these results with scanned images of the bone and describe the correlations on the basis of a mathematical model. This should make it possible in future to determine the strength of a bone directly from the CT scanner images. The scientists have already performed the first examinations on prepared and thus preserved bones, and plan to induce oscillations in unprepared bones left in their natural state over the coming months. The researchers hope that in about two years’ time, doctors will be able to obtain a realistic simulation model of unprecedented quality from computer tomography data. The prostheses can then be perfectly anchored, and will be held safely in place for longer.

Martin Quickert | alfa
Further information:
http://www.fraunhofer.de/EN/bigimg/2009/rn01fo6g.jsp
http://www.fraunhofer.de/EN/press/pi/2009/01/ResearchNews012009Topic6.jsp

More articles from Medical Engineering:

nachricht Noninvasive eye scan could detect key signs of Alzheimer's years before patients show symptoms
18.08.2017 | Cedars-Sinai Medical Center

nachricht Water-filtered infrared-A (wIRA) overcomes swallowing disorders and hypersalivation – a case report
10.08.2017 | Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V.

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>