Synopsis
The overall goal of this case study is to provide the utility of Open Knee(s) - Generation 1 model for reproducing the outcome of a clinical test, the pivot shift, for evaluating mechanical function of the anterior cruciate ligament.
Use Case
The case is based on reproduction of a pivot shift loading scenario in a tibiofemoral joint model. The loading scenario was measured in a cadaver knee during pivot shift tests conducted by an orthopaedic surgeon. In follow-up robotics testing, this loading profile was adjusted for robotics testing of intact, ACL deficient, and ACL reconstructed knees. The use case aims for illustrating the capacity of the Open Knee(s) - Generation 1 model to reproduce the clinical differentiation of intact and ACL deficient knee in a virtual sense.
Simulation Aims
- To understand the role of ACL for stabilization of the joint during pivot shift testing (primary)
- To explore the correspondence of Open Knee(s) simulation against robotics prescribed pivot shift loading of various knees (secondary)
Model
The model is based on Open Knee(s) - Generation 1 model, which was updated for FEBio version 2.1:
Inputs
Prescribed time histories of movement and loading of the tibiofemoral joint (six degrees of freedom) representative of pivot shift data:
- flexion
- internal/external rotation torque
- varus/valgus torque
- anterior/posterior force
- medial/lateral force
- compression/distraction force
Outputs
- Time histories of kinematics-kinetics of the tibiofemoral joint (six degrees of freedom) (primary)
- flexion torque
- internal/external rotation
- varus/valgus
- anterior/posterior translation
- medial/lateral translation
- compression/distraction
- Time histories of stress-strain behavior (secondary)
Simulation Conditions
- with intact ACL
- without the ACL (very low stiffness for convenient modeling and simulation workflow)
Team Members
- Ahmet Erdemir - study planning, outline of publications
- Snehal Chokhandre - execution of simulations and post-processing, lead authorship in publications
- Craig Bennetts - assisting simulations, scripting for pre-/post-processing, support to document model in publications
- Tara Bonner - assiting pivot shift trajectory generation, support documentation on pivot shift literature and implications of simulations for robotics testing
- Robb Colbrunn - lead pivot shift trajectory generation, provide literature survey on pivot shift studies (clinical and cadaver testing), support to document implications of simulations for robotics testing
- Paul Saluan - support to document clinical utility of pivot shift and implications of simulations for clinical practice
Progress
Source Code Repository
https://simtk.org/svn/openknee/app/PivotShift/
Data
https://simtk.org/svn/openknee/app/PivotShift/dat/
Model Customization
https://simtk.org/svn/openknee/app/PivotShift/src/
Simulations
Post-Processing
https://simtk.org/svn/openknee/app/PivotShift/sol/
Publications
https://simtk.org/svn/openknee/app/PivotShift/doc/