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Responses to my query: FujiFilm in the tibiofemoral joint

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  • Responses to my query: FujiFilm in the tibiofemoral joint

    Dear Colleagues

    I sent the following query on 23rd December 2010.
    I'm trying to perform some experiments with sheep knees to find out the force
    distribution pattern in the tibiofemoral joint. I need to put FujiFilm pressure
    sensitive sheets below the meniscus and press the whole joint. Now we have some
    practical difficulties for which I would be grateful if anybody can share their
    experience and comments:
    1- The menisci slide and move under load.
    2- The FujiFilm sheets slide and stick out of the joint under pressure
    3- We want to put two or three different sheets of different pressure range on
    each other to capture a wider range of pressures. How can we fix the sheets on
    each other so that they do not slide and move relative to each other.
    4- To protect the sheets from the humidity of the joint surfaces, we put a sheet
    of thin plastic (normal kitchen plastic bags) around them. Is there any better
    option?
    Thank you very much in advance for your comments.

    Several replies came immediately, but unfortunately my mailbox somehow deleted them and I was left with only two replies. I would like to ask those colleagues who have sent me a reply, to kindly resend them. Then, I will write an update to this message in the forum.

    The replies I have are from:
    1- Clifford Beckett
    2- Axel Kalpen

    Thanks a lot for your kind help.

    Feras Hakkak
    PhD candidate in biomechanics
    Biomedical Engineering Department
    AmirKabir University of Technology
    Tehran, Iran
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    1. Clifford Beckett (beckett@msu.edu):

    Hello Feras,
    ***** We have experience in using Fuji pressure film inside of joints.*** When we use the film, either in single pressures or* multiple pressure levels, we seal the pressure film in small plastic bags that we custom make to the hold the sheets tightly in place on top of each other.** The bags are made from polyethylene and are similar to the bag material that is used in thermal food storage bags which are designed to seal food to be placed in the freezer (freezer storage bags).** We cut the film slightly larger* (3 - 5mm) than the desired sheets and use a small hot temperature controlled iron to touch the edges and form a seal.** The iron we use is* the one used for thermally shrinking the plastic skin on remote controlled model airplanes.** So* it is available from hobby supply stores like Tower Hobby for $19.95 Tower Hobbies Sealing Iron.

    Cardinal medical supplies source for Steri-lok bags

    3M catalog description of steri-lok bag 8251

    To hold the bag in position during a test and to mark its orientation during a test, we place some short small pins or needle(s) into the bone-joint at some location outside of our area of pressure interest. I will have to check with our lab personnel to find out what kind of pins we use and how we place them.
    I hope this helps you. I should be able to come up with a medical journal article that describes this process based from one of our published studies.

    We have found that the film calibration changes when the pressure is applied for only a short period of time, and it changes if you stack the pressure films on top of each other. So, we found that we had to create our own custom calibration curve by running tests on the film using the same pressure film packages (stacks of film in the plastic bags) and testing at the same rate and duration of loading that we were going to use on our specimens. We used a Microtek brand color scanner to scan the film. Our Microtek scanner did better than our HP scanner at converting the red pressure film into gray scale images that the HP ones did. We used Sigma Scan software to convert the grayscale image data into numeric intensity data and convert the intensity data back into pressure numbers. If you sent the film into Fuji for analysis the numbers you get back would not be accurate because they assume long duration (several seconds long) application of pressure to expose the film and they do not take into account the plastic bag or multiple layer stacking. You could use them, in place of purchasing a scanner, to scan the images and return the raw (256 bit) gray scale image data. But, you would still need to create your own custom calibration curve and image analysis routines. Eric Meyer has gone through this process and may have some instructions about how he did this process.

    I talked with Eric and he said he used the NIH Image program ( which is now called Image J) which can be downloaded for free from http://rsbweb.nih.gov/ij/
    to calibrate the pressure film and analyze the images. I have some old S.O.P. s (standard operating procedure) files which describe how we did it a few years ago, but I need to get permission from our lab director before I can send copies of these files to you.
    Hope this helps. This may be all the information I will be allowed to share with you.

    Clifford L. Beckett office: 517-355-4659
    Electronic System Designer cell: 517-449-8226
    A411 E. Fee fax: 517-353-0789
    OMM Department email: beckett@msu.edu
    Michigan State University web: www.obl.msu.edu
    East Lansing MI, 48824

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    2. Axel Kalpen (axel.kalpen@novel.de):

    Dear Feras,
    Just received your request from Biomch-L. Please feel free to have a look at http://novel.de/novelcontent/pliance/knee

    for a system, which allows you to measure the pressure distribution dynamically. For this application a pliance pad with 256 individually calibrated, capacitive sensors is used, which is connected to the pliance analyzer and transmitts the data wireless to the PC.

    The sensors can also be sterilized (Sterad by J&J) and have already been used in the OR for measurements on patients. An example for this is attached as video and also two pares describing the system.

    Please let me know, if you would like to receive more information. We have also a representative in Iran, the company Arang Teb.

    I am looking forward to hearing from you.

    With best wishes,

    Dr. Axel Kalpen
    Director Biomechanics
    novel GmbH
    Ismaninger Straße 51 | 81675 Munich, Germany
    Tel. +49 (0) 89 4177 67-0 | Fax. +49 (0) 89 417767-99
    mailto: axel.kalpen@novel.de
    Geschäftsführer/ CEO: Dipl.-Ing. Peter Seitz
    Amtsgericht München/ Registered Office: Munich HRB 56124
    http://www.novel.de

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