Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Aircraft technology helps diagnose artificial hip, knee problems

21.02.2003


To assess the wear and tear on jet engine parts, mechanics used an old technology called ferrography to run the aircraft’s lubricating fluid through a magnetic device to separate out metal shavings and other ferrous engine debris. A University of Rhode Island researcher uses a similar process to assess the wear and tear on artificial hip and knee joints so patients can reduce the number of follow-up surgeries they must undergo or reduce the time spent in revision surgery.



Donna Meyer, an assistant professor of mechanical engineering, anticipates using her research to create a "wear atlas" that can be used by orthopedic surgeons as a diagnostic tool. She said the atlas could be used to help identify the potential problems that patients are having with their implants prior to revision surgery.

Most artificial hips consist of a polyethylene socket and metal ball or metal-on-metal combinations that are connected to adjoining bones with screws or cement. Total knee replacements are made of similar materials. Over time as the ball, socket and bone rub against each other, tiny debris is produced and settles between the bone and the implant interface, discouraging the much needed growth of bone around the prosthesis. This contributes to the loosening and separation of the interface, which necessitates revision surgery to repair it.


"Polyethylene wear debris can be a significant problem for patients because a loosened joint can cause great discomfort," said Meyer, a Cranston resident. "If we can determine the number and size of wear debris contained in a patient’s synovial fluid, and also look at the ratio of polyethylene to other constituents like metal, bone, and cement particles, we can create a tool to assist in diagnosing the problem with the implant before surgery is necessary. Ultimately we would like to minimize the number of revision surgeries that patients face, or at least minimize the amount of time spent in surgery for additional operations."

Meyer takes a sample of a patient’s synovial fluid — " it’s a large component of the lubricating fluid around your knee or hip," she said — and uses a process called bio-ferrography to capture the tiny particles of polyethylene, metal, bone and cement using a very strong magnet. Since most of the wear debris isn’t magnetic and therefore wouldn’t be collected by the device, she adds to the fluid sample a magnetic compound that binds to the non-magnetic particles.

"We need to capture every tiny particle in each sample to make sure the atlas is accurate," said Meyer, whose research is funded by the National Science Foundation and the Rhode Island Biomedical Research Infrastructure Network.

Meyer’s interest in this research was sparked when she was a graduate student at Rensselaer Polytechnic Institute studying the lubrication of artificial hip joints. She talked to the chief of orthopedic surgery at the time at Albany Medical Center, who told her of his interest in bio-ferrography. She’s been researching the subject ever since.

Once she perfects the technique for collecting the wear debris, she will begin creating the atlas. Meyer said the atlas will be designed so doctors can easily compare a patient’s age, activity level, implant type and time since implantation with the size and composition of the wear debris to quickly determine which part of the implant is the likely cause of the problem. For example, small particles are more likely to lead to implant loosening. Large pieces of debris, on the other hand, contribute greatly to the wear volume, but it is not certain how much it contributes to implant loosening, if at all.

"The atlas can be used by doctors as a maintenance guide, in addition to a radiograph for example, and hopefully give more information about early wear detection, just like the guides used by aircraft mechanics," she said.

Todd McLeish | EurekAlert!
Further information:
http://www.uri.edu/

More articles from Process Engineering:

nachricht Design treatment of advanced metals producing better sculpting
08.03.2019 | Purdue University

nachricht Laser Processes for Multi-Functional Composites
18.02.2019 | Fraunhofer-Institut für Lasertechnik ILT

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: The taming of the light screw

DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.

The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...

Im Focus: Magnetic micro-boats

Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.

The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Solving the efficiency of Gram-negative bacteria

22.03.2019 | Life Sciences

Bacteria bide their time when antibiotics attack

22.03.2019 | Life Sciences

Open source software helps researchers extract key insights from huge sensor datasets

22.03.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>