Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Medtec 2015: Getting the perfect fit for artificial hips

08.04.2015

When a patient receives a new hip, it is usually adjusted only approximately to leg length. Greater accuracy requires a more precise measuring process as well as adjustable implants. Now, a new type of measurement method coupled with a modular implant should allow orthopedic surgeons to precisely calibrate leg length after the operation so it matches its original length. The researchers will be introducing their development at the Medtec expo in Stuttgart, April 21-23 (Hall 7, Booth B04).

A painful hip that feels unstable and no longer has the same range of motion: For many patients, this means they need a prosthetic hip – something that happens to more than 200,000 people each year in Germany alone.


Modular hip implant.

© Fraunhofer IWU


Measuring system for determining leg length.

© Fraunhofer IWU

Implant manufacturers face numerous challenges; for example, the artificial joints may eventually break. In addition, orthopedic surgeons currently have no suitable method for precisely measuring leg length before the operation or for adjusting the implants accordingly.

The result is that after the operation, the leg can actually be longer or shorter than it used to be. This leads to problems with the spine, which have to be resolved using shoe inserts.

There’s a better solution on the horizon: With the completely new measuring technique developed by the Fraunhofer Institute for Machine Tools and Forming Technology IWU, orthopedic surgeons will be able to measure their patients’ leg lengths much more precisely.

The Fraunhofer researchers collaborated on the new system with several project partners: the Clinic for Orthopedics, Trauma Surgery and Plastic Surgery at the Leipzig University Hospital; University of Applied Sciences Zwickau and its Research and Transfer Centre; AQ Implants GmbH; and MSB-Orthopädie-Technik GmbH.

“The margin of error in our process is less than one centimeter,” explains Dr. Ronny Grunert, a researcher at IWU. “Eventually we’d like to get that down to five millimeters.” Currently, the usual procedure calls for the doctors to determine leg length with a tape measure, which can lead to errors of up to two centimeters.

Here’s how it works: With the patient in a prone position, the doctor affixes a small plastic box containing two LEDs to the patient’s shin. The doctor then takes hold of the patient’s heel and lifts it upward. With that motion, the two lights trace an arc that is recorded by a camera positioned about 1.5 meters to the side of the patient.

The principle is similar to that of a compass. The hip joint, from which the leg “hangs,” is essentially the point of the compass, while the LEDs act as the pencil. If the distance between the two changes, i.e. if the leg becomes shorter or longer, that will change the arc traced by the LEDs. The doctor takes this measurement twice – once right before the operation and once after the implant has been temporarily inserted. The box remains on the leg during the operation.

A software program compares both arcs to determine if the leg is the same length it was before the procedure. If necessary, the doctor can make adjustments to the artificial hip. Initial testing of a measuring system prototype has already met with success at the Leipzig University hospital. There are plans for a clinical trial later this year, and the new system could be on the market in about two years.

Unbreakable, adjustable hip implants

Fraunhofer’s researchers also optimized the hip implants, again working together with partners from industry, medicine and research. “We’ve developed an implant that can be adjusted to each individual patient,” says Grunert. The trick was to do away with prefabricated implants in various sizes and use a modular system instead.

In this method, the doctor can select the right hip stem as well as the right neck for each patient. Special screw connections are used to attach the individual parts to each other and the combined unit is implanted in the hip for testing. The doctor now measures the leg length, and, if necessary, can easily separate the implant’s various components to exchange them for better-fitting parts or adjust them as required.

Another advantage is that the artificial hip is less prone to breakage than conventional modular models with a conical clamping ring. Currently, the doctor connects the stem and the neck of the prefabricated artificial hip during the operation with a well-placed stroke of the hammer. This puts tremendous stress on the connection point, a conical clamping ring.

Furthermore, once the parts have been joined together, it’s virtually impossible to separate and adjust them. That’s not the case for the specialized screws that hold the parts of the new implants together. The point where they connect is mechanically stable and prevents the implant from breaking.

The new system was developed within the “artificial joints” cooperative network, which is funded by the Federal Ministry for Economic Affairs and Energy (BMWi) and coordinated by Fraunhofer IWU. At the Medtec expo, the researchers will present the leg-length measuring system and the modular hip implant as well as the artificial joint network.

Weitere Informationen:

http://www.fraunhofer.de/en/press/research-news/2015/april/getting-the-perfect-f...

Britta Widmann | Fraunhofer-Gesellschaft

More articles from Trade Fair News:

nachricht Functional films and efficient coating processes
14.02.2017 | Fraunhofer-Gesellschaft

nachricht Nanotechnology for life sciences and smart products: international innovations with IVAM in Tokyo
07.02.2017 | IVAM Fachverband für Mikrotechnik

All articles from Trade Fair News >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Biocompatible 3-D tracking system has potential to improve robot-assisted surgery

17.02.2017 | Medical Engineering

Real-time MRI analysis powered by supercomputers

17.02.2017 | Medical Engineering

Antibiotic effective against drug-resistant bacteria in pediatric skin infections

17.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>