Overview

This page provides specifications of knee specimen OKS002. This is a (possibly osteoarthritic) elderly female specimen candidate.

TableOfContents()

Specimen Characteristics

Right knee

Gender: Female

Age: 67 years

Race: White

Height: 1.55 m

Weight: 45.3 kg

BMI: 18.9

Serologically tested: Yes

X-Ray:

Experimentation

-- ["aerdemir"] DateTime(2014-11-03T14:19:24Z) All, please complete relevant sections of this page during and after experimentation.

Specimen

Reference Specification: ["Specifications/Specimens"] - [http://wiki.simtk.org/openknee/Specifications/Specimens?action=recall&rev=40 Revision as of November 2, 2014]

Leading Team Member: Snehal Chokhandre

Supporting Team Members: Ahmet Erdemir

Timeline: November 2, 2014 @ ~ 9:00 AM (specimen pulled out of freexer)

Data Location: In this page.

Protocol Deviations:

  1. Specimen was placed tibia first in the scanner.

Notes:

  1. None.

Specimen Preparation

Reference Specification: ["Specifications/SpecimenPreparation"] - [http://wiki.simtk.org/openknee/Specifications/SpecimenPreparation?action=recall&rev=130 Revision as of November 3, 2014]

Leading Team Member: Tara Bonner

Supporting Team Members: Snehal Chokhandre, Craig Bennetts, Ahmet Erdemir, Eryn Merico

Timeline:

Data Location:

Protocol Deviations:

  1. In specimen dissection, proximal and distal tissue regions (for femur and tibia, respectively) were marked as 4.5 inches. This is needed to accommodate symmetric bone cutting levels, which was recently incorporated in the specifications. THIS IS A SPECIFICATION UPDATE to accommodate flipping of the joint between tibiofemoral and patellofemoral testing.

Notes:

  1. A soft copy of serological testing for this specimen and all others should be placed in the in-house data management system in the appropriate specimen folder.
  2. Specimen was thawed for 24 hours unwrapped. This may be a good guideline to update specimen preparation specifications.
  3. For patella registration and Optotrak marker alignments, brass base plugs were used. Note that the use of a plug simply ensures referencing of the marker sets to the same position and orientation.
  4. For patella registration and Optotrak marker alignments, the order of divot probing was the same as oks001. A picture is available to denote this order, which should be included in specimen preparation specifications.
  5. One of the femur registration markers was placed anterolaterally rather than anterior or anteromedially.
  6. Data from coordinate system optimization (passive flexion) and pre-conditioning are also collected if needed.

Joint Imaging

Specimen Preparation

Reference Specification: ["Specifications/SpecimenPreparation"] - [http://wiki.simtk.org/openknee/Specifications/SpecimenPreparation?action=recall&rev=130 Revision as of November 3, 2014]

Leading Team Member: Craig Bennetts

Supporting Team Members: Snehal Chokhandre

Timeline: ~1:00 PM - 2:00 PM November 3, 2014 (patella registration marker will be placed next day)

Data Location:

Protocol Deviations:

  1. None

Notes:

  1. None.

Imaging

Reference Specification: ["Specifications/ExperimentationAnatomicalImaging"] - [http://wiki.simtk.org/openknee/Specifications/Specimen/ExperimentationAnatomicalImaging?action=recall&rev=120 Revision as of November 4, 2014]

Leading Team Member: Craig Bennetts

Supporting Team Members: Snehal Chokhandre

Timeline:

Data Location:

Protocol Deviations:

  1. Specimen was inserted tibia first in scanner.

Notes:

Joint Mechanics

Equipment Preparation

Reference Specification: ["Specifications/PressureCalibration"] - [http://wiki.simtk.org/openknee/Specifications/PressureCalibration?action=recall&rev=17 Revision as of November 4, 2014]

Leading Team Member: Robb Colbrunn

Supporting Team Members: Ahmet Erdemir

Timeline: 9:30 AM - 11:40 AM November 4, 2014

Data Location:

Protocol Deviations:

Notes:

  1. Sensor model is 5051, label is 5051-P1-16813DT1-1200.
  2. Equilibration pressure is 6.21 bars. Equilibration is done with Equilibration-1 and Equilibration-2; files are saved as single pass and double pass accordingly. Equilibration files are available in the oks002 folder of pressure sensor measurement laptop.
  3. Calibration used single pass equilibration as double pass was problematic (maybe double pass equilibration needs two distinct loading). Calibration file is available in the oks002 folder of pressure sensor measurement laptop.

Specimen Preparation

Reference Specification: ["Specifications/SpecimenPreparation"] - [http://wiki.simtk.org/openknee/Specifications/SpecimenPreparation?action=recall&rev=130 Revision as of November 4, 2014]

Leading Team Member: Tara Bonner

Supporting Team Members:

Timeline:

Data Location:

Protocol Deviations:

  1. For patellofemoral joint testing, grommets were not used for placement of the pressure sensor. The knee was small. To place the sensor, the cavity of the patellofemoral joint was exposed. Without disrupting the surrounding capsular structure, the sensor insertion area was cleaned up. The sensor was curved transversely, which gave it some stiffness along the insertion direction, and pushed through the joint as far as possible. This may be a specification change to expedite preparation. The sensor was actually placed on the robot.

Notes:

  1. A woodscrew was used to fix fibula to the tibia. The bone quality of the specimen seemed low and a drill bit passed through these bones were loose. Therefore the drill bit was pulled out and a woodscrew was used to secure
  2. During potting bottoms of the tubes were 7.5 inches away from epicondylar axis. This needs to be updated in the specifications.
  3. During tibiofemoral joint mounting, the specimen appeared to be a valgus knee.
  4. For patellofemoral joint testing, the specifications need to provide the location of quadriceps tendon clamp attachment. The loop of the clamp should be slightly above the bottom plane of femur pot.

Testing

Reference Specification: ["Specifications/ExperimentationJointMechanics"] - [http://wiki.simtk.org/openknee/Specifications/ExperimentationJointMechanics?action=recall&rev=91 Revision as of November 4, 2014]

Leading Team Member: Tara Bonner

Supporting Team Members: Robb Colbrunn

Timeline:

Data Location:

Protocol Deviations:

Notes:

  1. Reproducibility tests (AP laxity at 30 degrees) used 5 seconds wait instead of 10 seconds wait of the actual laxity tests. This seem to be the case in all previous specimens and causes an issue at low forces only. The specifications may need to be updated to refer this test as reproducibility test and indicate its wait time.
  2. Quadriceps line of action was digitized in the order of inferior then mid then superior. This may need to be described in the specifications in more detail.

Tissue Mechanics

Specimen Preparation

Reference Specification:

Leading Team Member:

Supporting Team Members:

Timeline:

Data Location:

Protocol Deviations:

Notes:

  1. Semitendinosus tendon was dissected and stored.
  2. Medial and lateral capsular components were dissected and stored.
  3. Fat bursa under patellar ligament was dissected and stored.
  4. ACL and PCL had fibrous and fatty connections, which were dissected.
  5. Fibula was dissected and stored.
  6. Femoral cartilage was divided into 9 regions (3 for medial condyle, 3 for lateral condyle, 3 for patellar groove) with 3 targeted for dissection (femoral grove, medial condyle - mid section, lateral condyle - mid section.
  7. Medial and lateral tibial cartilage was targeted to be dissected as a whole.
  8. Patellar cartilage had significant wear. The medial half that exhibited less wear was targeted for dissection.

Testing

Reference Specification:

Leading Team Member:

Supporting Team Members:

Timeline:

Data Location:

Protocol Deviations:

Notes:

Data Analysis

Pictured below are the Anterior Posterior laxity graph, the IR/ER laxity graph, and the Varus/Valgus laxity graph.

attachment:oks002_2LaxityGraphs.png

Modeling & Simulation