Recurring Meeting of Cleveland Clinic Core Team

Date: March 22, 2016

Time: 10:30 AM EST

Means: In person meeting


  1. Ahmet Erdemir
  2. Craig Bennetts
  3. Snehal Chokhandre


  1. Discuss immediate action items from the last meeting.
  2. Continue evaluation of drafts for data manuscripts.
  3. Discuss progress of tissue testing protocol evaluation.
  4. Decide immediate action items for the next meeting.
  5. Other.

Immediate Action Items:

Ongoing Action Items:



  1. Discuss immediate action items from the last meeting.
    • Craig returned back to the imaging manuscript to continue incorporating previously discussed recommendations.
    • Craig will catch up with work to document cartilage surface geometry resampling and geometry generation for other tissues.
    • Ahmet summarized the issues in contact pressure analysis results of some specimens, e.g. unit inconsistencies. He recommended Craig to check last meeting's minutes for details. He also mentioned the need for subplots and uniform scaling for patellofemoral joint testing manuscript. Craig will work with Robb to address these. Craig will also analyze contact pressures to determine anatomical sensor orientation.
    • Snehal has been able to cut the tissues more uniformly.
    • Snehal showed some data files from repeatability/reproducibility testing. All data for a specimen, including thickness measurements are saved in a folder with a read me file. Snehal described the testing process for a sample as i) choose the load cell based on tissue type/test, ii) assemble sample, iii) find contact at a low loading rate to identify 0.5 g compression or 1g tension (for 1k load cell), and with filtering (force control) - get absolution position to set starting position of the test, iv conduct test by first going to the absolute position obtained in previous step and subsequently move to relative positions for multi-step relaxation test; data are not filtered for stress relaxation. She repeated the same test on the sample after letting the sample rest for an hour. Later, she took out the sample, placed it back, and conducted the test again. Tissue thickness was measured by OTMS twice, before sample was assembled to the testing machine.
    • The group went over different tests and compared average moduli. Snehal calculated three moduli - by a line fit (not enforced to pass at zero stress-strain point), average of three moduli (from multiple steps), and a linear region moduli (between last two loading steps). For unconfined compression the moduli varied between tests. The group attributed these to the different resting times before each test, in or out of water.
    • For unconfined testing, the team decided to test two neighboring samples over a two day period. In the first day, the cartilage specimen will be removed from the freezer, thawed and samples will be prepared. Each sample will be kept in saline solution for an hour. In following, sample thickness will be measured and testing will be conducted. Later, samples will be refrigerated until the next day to repeat the protocol again. This scheme will allow the quantification of uncertainties associated with the sampling location and for the same sample due to testing protocol.
    • Snehal also showed repeatability data from confined compression and from tensile testing. It appears that the find contact threshold, e.g. 1 g, may be too low to identify the starting point for these experiments and to recruit the sample to desired strain levels. Ahmet recommended Snehal to increase this threshold. She may want to do this for unconfined compression as well. It is advisable do some tests up to failure to determine actual range of tissue responses.
    • There was a discussion on the resolution of the force transducers. The reported resolutions will likely be with filtering. Ahmet recommended to collect unfiltered force data at unloaded states (static or with a movement profile) and calculate the RMS error to quantify load cell resolution in practice.
  2. Continue evaluation of drafts for data manuscripts.
    • Robb, Tara, and Jason were not available. Manuscript discussions will continue in following weeks.
  3. Discuss progress of tissue testing protocol evaluation.
    • See relevant notes in the discussions of immediate action items from the last meeting.
  4. Decide immediate action items for the next meeting.
    • See Immediate Action Items above.
  5. Other.
    • Ahmet discussed various Open Knee(s) related projects with Snehal and Craig. He has been trying to prioritize the work to follow current Open Knee(s) activities.

RecurringMeetings/2016-03-22 (last edited 2016-05-04 22:09:47 by localhost)