Recurring Meeting of Cleveland Clinic Core Team
Date: July 29, 2014
Time: 10:30 AM EST
Means: In person meeting
Attendees:
- Ahmet Erdemir
- Jason Halloran
- Craig Bennetts
- Snehal Chokhandre
- Katie Stemmer
- Robb Colbrunn
- Tara Bonner
Agenda:
- Discuss immediate action items from the last meeting.
- Discuss pilot specimen testing outcomes.
- Decide immediate action items for the next meeting.
- Other.
Immediate Action Items:
- All
- Update oks004 wiki page to provide information on specimen-specific experimentation.
- Recommend changes in specifications based on oks004 testing experience in the oks004 wiki page.
Notes:
1. Discuss immediate action items from the last meeting.
- Ahmet asked everyone to update the oks004 wiki page to reflect what was learned, especially related to their specific tasks, during the pilot test. This page will document any deviations from the existing specifications, which includes recommendations by the team members, and allow the community/group to decide the changes that may be needed in the general specifications. One time deviations may happen, and they should be noted in each specimen's page. One example would be to document the fact that the tibia was mounted “up” and the team can discuss whether this is a general change or specific to this knee.
- Snehal began updating her sections in the experimentation summary of the oks004 knee, which effectively serves as a pilot test as it is outside the desired specifications for actual Open Knee(s) specimens. Ahmet addded protocol deviations as well as notes, that may not be currently included in the notes.
- The team briefly discussed options for tibia and femur registration, which includes rapid prototyping more “round” spheres, as opposed to using the existing hollow spheres.
- Craig noted filling the lead and supporting team members for each task from the pilot testing would help the team know where they need to their efforts. Time was spent documenting each of these sections with the appropriate team members.
2. Discuss pilot specimen testing outcomes
- Related to the above discussion, everyone has a task to update their sections in the notes for the oks004 pilot testing.
- Snehal noted that the fellow (who helped with tissue testing preparation) managed to excise the MPFL and medial and lateral capsule for future testing.
- The fellow noted the specimen was “healthy” with no obvious signs of degradation.
- Major hurdles during the test were discussed. Specific to preparation, thawing required approximately 22 hours. One issue that was not previously discussed was fixation of the fibula. It was fixed during the testing by passing a drill bit through to the tibia. The issue may be that the knee should also be imaged in this state, though obviously metal should not be used. Various potential solutions were discussed, which included plastic fixation for imaging replaced by a metal screw before the actual testing.
- Another hurdle, specific drill bit sizes had not been tested/decided and time was wasted determining the pilot hole sizes that were needed for the various holes/screws (plugs and registration spheres).
- General deviations have already been noted, including potential solutions that were implemented “on-the-fly.”
- Snehal noted the figure for specimen preparation for imaging needs to be updated to reflect what was actually done before the testing.
- Regarding imaging, at first glance the images look acceptable. Related, specific documentation concerning the “localizer” and setup of the location of the field of view (e.g. the center of the images) needs to be documented. This includes making sure the registration markers are included in the general imaging set (the isotropic 0.5 mm square image acquisition settings).
- The largest deviation in the tibiofemoral testing was mounting the tibia up, as opposed to the femur. This allowed direct measurement of the tibia reactions, as opposed to measuring reactions through the flexion axis (includes resolution through two transducers).
- For patellofemoral testing, the orientation of the knee had to be turned on the platform so that the quadriceps actuator acted directly above the patella. Digitization of this line of action was not well documented and also needs to be updated. Ahmet thinks one sensor per knee is appropriate, especially given the troubles in putting the sensor in the joint. Using the same sensor again may be risky. Ahmet is inclined to keep the current specifications and try this protocol again on the next knee. The current approach needs to be documented in more detail on the wiki. The sensor that was used for the pilot testing should probably be re-calibrated to compare with the pre-testing calibration results (by applying both calibration files to the same sensor results).
- The surgeon (a fellow) helped dissect the knee. Snehal has 30 tests to perform, which encompasses 22 samples (confined and unconfined compression tests on the same samples). Snehal noted the cartilage was harvested on the following day, which was not ideal. Snehal asked that we start a bit earlier to avoid another day in the fridge.
- Of note, tendon samples from the foot were acquired and tested in parallel with the knee tests, both joint and tissue tests. Consistent environmental conditions were adopted and a simplified loading regime (a shortened stress relaxation test) was used. If drastic changes are noted, this may warrant a study focused on the potential for tissue degradation throughout the testing.
- For thickness/width measurement, Snehal notes we still do not have a “good” optical measurement approach. This data will compliment the robot data as well as provide an estimate of the poisson effect for changes in sample cross section during testing.
- Specific to tissue testing, Snehal noted it is still challenging to fit all required tests for a single specimen in one day, especially for the compression tests. The result is another day out of the freezer, which is not ideal. Snehal will document the required time for each test so that they can be fit into a single day per sample. Logistics will be worked out but options include using multiple personnel (as Tara noted) to support the testing.
- Including the offsets in the left to right knee conversion for kinematics description is being worked on by Robb. Ahmet noted that a “sanity check” should be performed to verify matrix results yield expected results, e.g. varus prescription actually moves a knee in varus, etc. Coordinate frame verification needs to be performed first for the J2C data before it is published, and then for the pilot testing (oks004).
- Ahmet uploaded most, if not all, of the oks004 data to the Midas platform. It's relatively unorganized at this point but it will be cleaned up as the data is used.
3. Decide immediate action items for the next meeting.
- Immediate action items were discussed and agreed upon.
4. Other
- None noted.