Recurring Meeting of Cleveland Clinic Core Team

Date: May 27, 2014

Time: 10:30 AM EST

Means: In person meeting


  1. Ahmet Erdemir
  2. Jason Halloran
  3. Snehal Chokhandre
  4. Elvis Danso
  5. Katie Stemmer
  6. Robb Colbrunn
  7. Tara Bonner
  8. Emily Oliver


  1. Discuss immediate action items from the last meeting.
  2. Discuss tissue testing progress.
  3. Decide immediate action items for the next meeting.
  4. Other.

Immediate Action Items:


  1. Discuss immediate action items from the last meeting.
    • Snehal gave a high level overview of the project for the two first-time attendees of the Open Knee(s) meeting (Emily and Katie, see attendee list above).
    • Jason covered his progress for uploading the scripts related to patella registration. The sphere fitting algorithm will include the source code licensing; it is same as Open Knee(s). Other scripts, e.g., for singular value decomposition) will also be uploaded.
    • Jason also updated the picture for the patella registration hardware. The task also stated to “update the extensor mechanism” description though this was unclear as to the specific task desired. It was decided Tara and Jason will update the description of the “clamp” used to secure the quadriceps tendon to the actuator.
    • Snehal covered the tissue testing room preparation and summarized accessories that need to be manufactured. Installation of eye wash station is pending, which is one of the last items before the mechanical tissue testing equipment can be moved into the room. The vibratome was already moved into the new space. Tony Shawan (Prototype Core) has not completed the tall bath with flat walls for tissue testing. Snehal was informed that this will be completed this week.
    • Snehal clarified the tissue harvesting procedures in the specimen preparation page. Snehal also updated the group on the tissue testing progress. The thickness measurement test problem has not been completed but Snehal will likely start that today. Martin Garon (from Biomomentum Inc.) replied to Snehal's latest email. The single axis resolution of the load cell may be modifiable as per Martin's suggestion. Sampling of video data at different rates, to accommodate the high strain rate initial response followed by the stress relaxation (fewer data points are needed during stress relaxation) was also discussed. After stress relaxation tests the specimen could be retested with two separate protocols, one a ramp load (without stress relaxation) with a high video sampling rate and another a low strain rate loading to obtain the quasi-static response with a low video sampling rate. This may not be exactly equivalent to the original loading, especially if the preconditioning and the tissue state (water content) is not in the same state. Another possibility is the resampling of the video data immediately after the test is done with video data acquired at the maximum capacity.
  2. Elvis prepared the tensile samples last week with Snehal's help. Sample ligament, meniscus and cartilage tensile testing with the new system is near completion. Snehal will provide a summary of the data for ligament testing in the upcoming weeks. Related to completion of Elvis' tissue testing protocols, the BioRobotics Core will be using the robot over the next two days. Elvis may need to isolate his testing setup to prevent others interfere with data collection during tissue testing, e.g. tape off the area to limit potential bumping of the testing equipment.

    • Ahmet covered the meeting he and Craig had with the team at Stanford University. The post-processing test problem was prepared and will be incorporated into cloud computing prototype. Joy Ku (from Stanford University) would like to demo this feature in the upcoming World Congress of Biomechanics.
    • Tara uploaded a new image of the Optotrak probe and also sent Robb and Jason a picture of the tendon clamp hardware. These pictures will be added to the wiki.
  3. Discuss tissue testing progress.
    • Ahmet summarized the approach for uniaxial tensile testing of the ligaments. One issue is specifying the “zero force” or the tarring condition. This value should potentially be specified as a stress value to accommodate different size samples and can be adjusted for different tissue types to accommodate similar initial strains. The resolution of the load transducer should be accommodated to reach a target stress value, which should be as low as possible. As it stands, a minimal stress will be targeted as the pre-load value, and the corresponding load will be calculated and compared to the capability of the machine. If the transducer is not capable of registering the desired load, the pre-stress value will be increased to the capacity of the testing system. Note that the zero load condition (inflection point as force accumulates) of the sample can be obtained once the data is collected. Nonetheless, this initial referencing with a target stress value will ensure that stress-relaxation tests span both the toe and linear regions of the tissue stress-strain response.
    • There's a potential for a phase lag in the data collection if filtering of force measurements is turned on. While data filtering may enhance identification of the tarring state, its influence on the data should be evaluated before any further use.
  4. Decide immediate action items for the next meeting.
    • Action items were discussed and agreed on; see Immediate Action Items above.
  5. Other.
    • Robb will add documentation of the “right knee abstraction” issue for joint testing. Necessary coordinate systems that needs to be provided in the "physical representation" should be identified so that proper interpretation and registration is achieved.
    • Robb updated the group on the new motors for the robot. They should arrive next week.

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