DU01

Authors

Center for Orthopaedic Biomechanics
Michael D. Harris, PhDFollow
Kevin Shelburne, PhDFollow

Files

Archive Date

2015

Keywords

knee, biomechanics, laxity, in vitro, finite element

Disciplines

Biomechanics and Biotransport | Biomedical Engineering and Bioengineering

Recommended Citation

Harris MD, Cyr AJ, Ali AA, Fitzpatrick CK, Rullkoetter P, Maletsky L Shelburne KB. A combined experimental and computational approach to subject-specific analysis of knee joint laxity. J Biomech Eng. 2016. 138(8). Ali AA, Shalhoub SS, Cyr AJ, Fitzpatrick CK, Maletsky LP, Rullkoetter PJ, Shelburne KB, 2016. Validation of predicted patellofemoral mechanics in a finite element model of the healthy and cruciate-deficient knee. J Biomech 49:302-9.

Specimen Description

Age: 50 y/o; Sex: Male; Weight: 127.01 kg; Height: 175 cm; BMI: 41.35

CT Image Acquisition Details

251 slices; thickness: 0.6 mm; In-plane pixel spacing (mm): 0.390625 x 0.390625; In-plane resolution: 512 x 512; Tube Current: 186 mA; Peak kV: 120

MR Image Acquisition Details

Sequence: T2 trufi3d_we_SAG; 192 slices; thickness: 0.6 mm; in-plane pixel spacing (mm): 0.53125 x 0.53125; in-plane resolution: 320 x 320

Document Type

Data Set

Kinematics and Load during Laxity Testing Data Details

We have provided kinematic and loading data for knee envelope (i.e. laxity) tests of intact knees and following resection of the cruciate ligaments. Please refer to and cite the following for details about the data collection process: Harris MD, Cyr AJ, Ali AA, Fitzpatrick CK, Rullkoetter P, Maletsky L, Shelburne KB. A combined experimental and computational approach to subjects-specific analysis of knee joint laxity. J Biomech Eng. 2016. 138(8).

For each knee, the kinematic and load data are subdivided by the experimental test being performed. For example, the initial sets of provided data were recorded during a passive knee envelope test with the knee intact (i.e. before resecting the cruciate ligaments or meniscus). Thus, the data are located in a folder called INTACT_KE for intact knee envelope.

Examples of the naming conventions for the Grood-Suntay kinematics and loads:

- DU02_INTACT_KE_AP.csv – These are kinematic and load data as the knee is being manually flexed between approximately 0 and 130 degrees and alternating anterior and posterior forces are being simultaneously applied. Although the anterior-posterior forces are predominant, we have supplied rotations, translation, forces, and torques in all 6 DOF.

- DU02_INTACT_KE_IE.csv – These are kinematic and load data as the knee is being manually flexed between approximately 0 and 130 degrees and alternating internal and external torques are being simultaneously applied.

- DU02_INTACT_KE_VV.csv – These are kinematic and load data as the knee is being manually flexed between approximately 0 and 130 degrees and alternating varus and valgus torques are being simultaneously applied.

- DU02_INTACT_KE_Passive.csv – These are kinematic and load data as the knee is being manually flexed between approximately 0 and 130 degrees.

In addition, Excel files are included with intact and ligament-resected data following processing of the experimental data that separated the response of the knee into three loading directions: varus-valgus (VV), internal-external (IE), and anterior-posterior (AP). The naming convention is for example: “DU02_Resected_experimental_processed”

3D Reconstruction Details

We have supplied subjects-specific reconstructions of the bone and cartilage geometry of the femur, tibia, fibula, femoral cartilage, and tibial cartilage for each of the cadaveric knees. The reconstruction files are in STL ASCII format. These reconstructions come directly from segmentation of the MR images and have not undergone the refinement and additional smoothing for finite element modeling. It is left to the user to use the reconstructions as desired.

An example of the naming convention for reconstruction files:

- DU02_Fem_Bone.stl – This is the femur bone reconstruction for knee # DU02

NOTE: On the DU01 knee, the bones were segmented from CT data and then aligned to the cartilage, which had been aligned from the MRI. All other knees were segmented entirely form the MRI.

Experimental Probe Points Details

For registration of bony structures during different testing protocols and for placement of soft-tissue meshes during finite element modeling, an Optotrak motion capture system and digitizing wand were used to probe several locations on the bone, cartilage, and ligament attachments. These probe points have been transformed to align with the 3D reconstructions and MR images.

The probed structures include: femur bone, tibia bone, articular geometry of the femur cartilage, tibia cartilage, and patella cartilage, and ligament attachment sites of the LCL, MCL, ACL, and PCL.

Examples of the naming convention for probed point files:

- DU02_ACL_Fem.txt – These are the probed ACL attachments on the femur for knee #DU02

- DU02_Fem_artgeo.txt – These are probed points on the articular cartilage surface of the femur for knee #DU02

Five points were digitized on bone (femur, tibia, patella), from which local coordinate systems were established. Using the local coordinate systems and data recorded from the Optotrak motion capture system data (i.e. from tracking bodies mounted to each bone), joint angles of the tibia with respect to the femur (TF), patella with respect to the femur (PF), and patella with respect to the tibia (PT) kinematics were calculated. The resulting kinematics and corresponding 6 DOF torques and forces, recorded by the load cell mounted on the tibia can be found in the Kinematics and Loads section.

DU02_Fem_GSPts.txt – These are the digitized points on the femur, used to establish a local coordinate system and calculate Grood-Suntay kinematics for the femur of knee #DU02

Publication Statement

License Agreement

Downloading any of the provided data indicates your compliance with the following license agreement.

USE AGREEMENT

Permission is hereby granted, free of charge, to any person obtaining a copy of this experimental, image, and computational model data, and associated documentation files (the “Data”) to be used without restriction to use, copy, merge, and publish the Data for non-commercial purposes, including but not limited to non-commercial research and non-profit teaching or learning. Permission is furnished subject to the following conditions: 1. Relevant publications by the University of Denver must be cited as the source the Data in all cases of publication or distribution. 2. Where applicable, University of Denver personnel will be included as co-authors in cases of publication. Use of the Data for any commercial application must be explicitly obtained by the University of Denver Center for Orthopaedic Biomechanics.

LIABILITY AGREEMENT

The Data is provided “as is” with no express or implied warranty or guarantee. The University of Denver and the Center for Orthopaedic Biomechanics do not accept any liability or provide any guarantee in connection with uses of the Data, including but not limited to, fitness for a particular purpose and noninfringement. The University of Denver and the Center for Orthopaedic Biomechanics are not liable for direct or indirect losses or damage, of any kind, which may arise through the use of this data.

CITATIONS

Knee Laxity Testing Data and Models: Harris MD, Cyr AJ, Ali AA, Fitzpatrick CK, Rullkoetter P, Maletsky L Shelburne KB. A combined experimental and computational approach to subjects-specific analysis of knee joint laxity. J Biomech Eng. 2016. 138(8). doi: 10.1115/1.4033882

Knee Extension Testing Data and Models: Ali AA, Shalhoub SS, Cyr AJ, Fitzpatrick CK, Maletsky LP, Rullkoetter PJ, Shelburne KB, 2016. Validation of predicted patellofemoral mechanics in a finite element model of the healthy and cruciate-deficient knee. J Biomech 49:302-9.

Kinematics and Load during Knee Extension Testing Data Details

We have provided kinematic and loading data from an experiment that used quadriceps force to extend the knee. Healthy patella joint motion is critical to healthy function of the knee joint. Patellar pathology leading to changes in motion and force in the joint can increase the risk of cartilage wear and the onset of arthritis. The objective of this study was to create a computer model representation of the patella-femoral joint to predict motion and forces across healthy and pathological specimens. Measurements from a series of dynamic cadaveric experiments were used to develop models of the knee for three specimens. Using the DU01, DU02, and DU03 specimens, quadriceps force was used to extend the knee while force and motion were recorded. Subsequently, the test was repeated with the anterior cruciate ligament and posterior cruciate ligament cut in each knee. Models of each specimen were constructed and calibrated to the outputs of the intact knee condition, and subsequently used to predict patella motion and loading in healthy and injured conditions. Complete details were recorded in:

Ali AA, Shalhoub SS, Cyr AJ, Fitzpatrick CK, Maletsky LP, Rullkoetter PJ, Shelburne KB, 2016. Validation of predicted patellofemoral mechanics in a finite element model of the healthy and cruciate-deficient knee. J Biomech 49:302-9.

Finite Element Models of Knee Laxity and Knee Extension

We have provided functioning calibrated finite element models and simulations of the DU01 knee during laxity testing and knee extension. The finite element method is a numerical technique used to build computer models of complex deformable structures and create simulations of these structures under real-world conditions. The input files are provided in Abaqus®, and require basic knowledge of the use of these methods. This project is in progress and models are added for download incrementally. Details of the models and simulations are provided in:

Harris MD, Cyr AJ, Ali AA, Fitzpatrick CK, Rullkoetter P, Maletsky L, Shelburne KB. A combined experimental and computational approach to subjects-specific analysis of knee joint laxity. J Biomech Eng. 2016. 138(8).

Ali AA, Shalhoub SS, Cyr AJ, Fitzpatrick CK, Maletsky LP, Rullkoetter PJ, Shelburne KB, 2016. Validation of predicted patellofemoral mechanics in a finite element model of the healthy and cruciate-deficient knee. J Biomech 49:302-9.