/
KneeSimulator.md
101 lines (67 loc) · 4.35 KB
/
KneeSimulator.md
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
---
gallery_title: "Knee Simulator Model"
gallery_image: "/Applications/images/KneeSimulator.webp"
---
(sphx_glr_auto_examples_Orthopedics_and_rehab_plot_KneeSimulator.py)=
(example_kneesimulator)=
# Knee Simulator Model
````{sidebar} **Example**
<img src="/Applications/images/KneeSimulator.webp" width="70%" align="center">
````
Model of a Knee Simulator using a knee implant model and force-dependent kinematics (FDK).
For an indepth description of the mathematics and mechanics behind FDK please see [^cite_azdn17].
**Main file:** `Application/Examples/KneeSimulator/AnyKneeSimulator.Main.any`
This is stand alone demo model of a knee simulator device resembling the principles of the Kansas Knee simulator [^cite_hcmt10].
The model is contructed as a stand-alone model and doesn't use any elements and body parts from the model repository (AMMR).
Data for the total knee replacement (TKR) implant comes from the [6th Grand Challenge Competition to Predict In Vivo Knee Loads](https://simtk.org/projects/kneeloads).
## Segments
The model is constructed of five main segments (femur, patella, tibia, ankle-fixture, and hip-fixture).
In practice more segments are included. The mass of the femur/tibia is implemented as separate segments
for easier specification of the moments of inertia. Likewise, the trans-spherical mechanism between ankle
and ground segments is implmented using three segments connected with revolute and slider joints.
:::{figure} /Applications/images/KneeSimulator_Full.jpg
:align: center
Overview of the knee simulator
:::
## Ligaments
The ligaments are modeled using one-dimensional nonlinear elastic spring elements. In order to prevent
ligaments from penetrating the bone/implant surfaces, they were wrapped around various geometrical shapes (cylinder, ellipsoid,...).
Ligament properties (stiffness and reference strains) were adopted from the literature [^cite_bkhg91] & [^cite_mvfk15].
:::{figure} /Applications/images/KneeSimulator_Ligaments.jpg
:align: center
Ligaments in the model, abbreviations adopted from [^cite_sbtp06] Figure 1.
:::
## Contacts
Three STL-based rigid-rigid contact models were defined: between the patella and femoral component, the femoral component and tibia insert (lateral side),
and the femoral component and tibia insert (medial side).
```{figure} /Applications/images/KneeSimulator_Contacts.jpg
:align: center
Contact surfaces in the model.
```
## Settings
Model settings can be added and removed here: `UserDefinedSettings.Main.any` to use FDK define:
```AnyScriptDoc
#define USE_FDK 1
```
Other adjustable settings include: ligament parameters, femur and tibia mass ratios, load applied to the hip fixture, and desired knee flexion.
```AnyScriptDoc
#define DEF_KNEE_FLEXION_MIN 10
#define DEF_KNEE_FLEXION_MAX 60
#define DEF_HIP_AXIAL_LOAD_MIN 200
#define DEF_HIP_AXIAL_LOAD_MAX 200
#define FEMUR_MASS_RATIO 0.135
#define TIBIA_MASS_RATIO 0.0465
#include "Input/Ligament_Properties.any"
```
Please note that this simulation is only a demo example.
[^cite_azdn17]: Andersen, M. S., de Zee, M., Damsgaard, M., Nolte, D., & Rasmussen, J. Introduction to Force-Dependent Kinematics: Theory and Application
to Mandible Modeling. J Biomech Eng. 139(9), 091001 (2017). doi: [10.1115/1.4037100](https://doi.org/10.1115/1.4037100)
[^cite_hcmt10]: Halloran JP, Clary CW, Maletsky LP, Taylor M, Petrella AJ, Rullkoetter PJ. Verification
of predicted knee replacement kinematics during simulated gait in the Kansas knee simulator. J
Biomech Eng. 132(8), 081010 (2010). doi:[10.1115/1.4001678](https://dx.doi.org/10.1115/1.4001678)
[^cite_bkhg91]: Blankevoort, L., Kuiper, J. H., Huiskes, R., and Grootenboer, H. J., “Articular Contact
in a Three-Dimensional Model of the Knee,” J. Biomech., 24(11), pp. 1019–1031, (1991). doi:[10.1016/0021-9290(91)90019](<https://doi.org/10.1016/0021-9290(91)90019-J>)
[^cite_mvfk15]: Marra, M. A. et al. A subject-specific musculoskeletal modeling framework to predict in
vivo mechanics of total knee arthroplasty. J. Biomech. Eng. 137, 020904 (2015). doi:[10.1115/1.4029258](https://dx.doi.org/10.1115/1.4029258)
[^cite_sbtp06]: Shelburne, K. B., Torry, M. R. & Pandy, M. G. Contributions of muscles, ligaments, and the ground-reaction force to tibiofemoral joint loading
during normal gait. J. Orthop. Res. 24, 1983–1990 (2006). doi:[10.1002/jor.20255](https://dx.doi.org/10.1002/jor.20255)