This page provides specifications of knee specimen OKS004. This is a pilot specimen to go over the whole experimentation process.

TableOfContents()

Specimen Characteristics

Right knee

Gender: Female

Age: 46 years

Race: White

Height: 62 in. (1.575 m)

Weight: 120 lbs. (54.43 kg)

BMI: 21.9

Serologically tested: Yes

X-Ray

Experimentation

Specimen

Reference Specification: ["Specifications/Specimens"] - [http://wiki.simtk.org/openknee/Specifications/Specimens?action=recall&rev=40 Revision as of April 28, 2014]

Leading Team Member: Snehal Chokhandre

Supporting Team Members:

Timeline:

Data Location:

Protocol Deviations:

1. Specimen Characteristics. Donor age (46 yrs) does not match specifications.

2. Specimen Size. The specimen is not hip to toe rather mid-femoral shaft to toe.

Notes:

Specimen Preparation

Reference Specification: ["Specifications/SpecimenPreparation"] - [http://wiki.simtk.org/openknee/Specifications/SpecimenPreparation?action=recall&rev=114 Revision as of July 9, 2014]

Leading Team Member: Tara Bonner

Supporting Team Members:

Timeline:

Data Location:

Protocol Deviations:

1. Femur Anatomical Landmarks. As the specimen did not include femoral head, landmarks on femoral shaft at its most proximal circumference were digitized.

Notes:

1. Registration Markers - Preparation. Drilling axis (for screw placement) and marker center are not concentric. Careful handling is necessary not to rotate the markers after their installation on bones. Preparation of the markers beforehand, by drilling on the lathe may be helpful to establish concentricity.

2. Registration Markers - Digitization. Digitization order for femur spherical markers are: 1 - anteromedial, 2 - medial, 3 - lateral. Digitization order for tibia spherical markers are: 1 - lateral, 2 - medial, 3 - posterior.

Joint Imaging

Specimen Preparation

Reference Specification: ["Specifications/SpecimenPreparation"] - [http://wiki.simtk.org/openknee/Specifications/SpecimenPreparation?action=recall&rev=114 Revision as of July 9, 2014]

Leading Team Member: Craig Bennetts

Supporting Team Members:

Timeline:

Data Location:

Protocol Deviations:

1. Patella registration marker assembly was not placed on the patella for imaging. This can be prevented by cross-checking with specifications. Alternative imaging or digitization is necessary to align patella local coordinate systems between imaging and motion analysis. This can be accomplished by i) imaging patella only with the registration marker assembly after dissection, or ii) by digitizing patella anatomy using Optotrak along with patella motion analysis markers. Snehal will follow up to resolve this issue.

Notes:

Imaging

Reference Specification: ["Specifications/ExperimentationAnatomicalImaging"] - [http://wiki.simtk.org/openknee/Specifications/ExperimentationAnatomicalImaging?action=recall&rev=117 Revision as of June 25, 2014]

Leading Team Member: Craig Bennetts

Supporting Team Members:

Timeline:

Data Location:

Protocol Deviations:

Notes:

Joint Mechanics

Equipment Preparation

Reference Specification: ["Specifications/PressureCalibration"] - [http://wiki.simtk.org/openknee/Specifications/PressureCalibration?action=recall&rev=11 Revision as of July 17, 2014]

Leading Team Member: Jason Halloran

Supporting Team Members:

Data Location:

Timeline:

Protocol Deviations:

Notes:

Specimen Preparation

Reference Specification: ["Specifications/SpecimenPreparation"] - [http://wiki.simtk.org/openknee/Specifications/SpecimenPreparation?action=recall&rev=114 Revision as of July 9, 2014]

Leading Team Member: Tara Bonner

Supporting Team Members:

Timeline:

Data Location:

Protocol Deviations:

Notes:

1. The specifications did not explicitly detail securing of the fibula to the tibia. A drill bit was passed through the fibula and the tibia to prevent fibula's movements during tibiofemoral joint testing. It may be necessary to secure fibula to the tibia during specimen preparation (before detaching the foot) to approximate anatomical alignment. This will require MRI compatible screws, etc. and will ensure keeping the fibula at the same position relative to the tibia in imaging and during robotics testing.

Testing

Reference Specification: ["Specifications/ExperimentationJointMechanics"] - [http://wiki.simtk.org/openknee/Specifications/ExperimentationJointMechanics?action=recall&rev=81 Revision as of May 25, 2014]

Leading Team Member: Tara Bonner

Supporting Team Members:

Data Location:

Timeline:

Protocol Deviations:

1. For tibiofemoral joint testing, the knee was assembled upside down. This approach circumvented the need for gravity compensation during force measurements. The tibia was fixed directly to the load transducer, which was assembled on the testing frame.

Notes:

1. For tibiofemoral joint testing, reprogramming of the robotics testing system was required to accommodate optimization of the joint coordinate system.
2. During tibiofemoral joint testing, the control system had issues loading the knee joint flexed at 90 degrees with a 2.5 Nm valgus moment from an unloaded state. This may be related to a possible singularity of the robot configuration.
3. During tibiofemoral joint testing at 90 degrees flexion, visibility of the femur Optotrak markers was problematic.

Tissue Mechanics

Specimen Preparation

Reference Specification: ["Specifications/SpecimenPreparation"] - [http://wiki.simtk.org/openknee/Specifications/SpecimenPreparation?action=recall&rev=114 Revision as of July 9, 2014]

Leading Team Member: Snehal Chokhandre

Supporting Team Members:

Timeline:

Data Location:

Protocol Deviations:

Notes:

Testing

Reference Specification:

Leading Team Member: Snehal Chokhandre

Supporting Team Members:

Data Location:

Timeline:

Protocol Deviations:

Notes:

Data Analysis

Modeling & Simulation