A human knee joint model considering fluid pressure and fiber orientation in cartilages and menisci

Abstract A three-dimensional (3D) finite element (FE) human knee joint model developed from magnetic resonance images (MRIs) has been validated with the sets of experimental results in a normalized scale. The performance of the 3D FE knee joint model has been tested, simulating a physical experiment. The experiment provided the direct measurement of anterior cruciate ligament (ACL) strains due to the forces of quadriceps muscle force (QMF) followed by ground reaction force (GRF) at low knee flexion. Accurate and precise anatomy has been obtained from segmented MRI images. The ACL strain subject to the loading was calculated and analyzed compared with the measured data from the experimental tests. The study shows that the pre-activated ACL strain, which is measured before the application of GRF, increased nonlinearly with increasing QMF before landing. However, the total ACL strain, which is measured after both QMF and GRF applied, reaches out to the limited constant value (6%) instead of crossing the ACL failure value. These results suggest that the forces generated from QMF and GRF at low flexion may not bring ACL to a failure level as presented in the experimental tests. The results of the FE model fall into the standard deviations of the 22 cadaveric knees testing results, which represents the successful mechanical modeling of ACL and the surrounding structures of the human knee joint. The model may further be used to investigate the risks of the ACL injury.

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Mechanical Response of Human Knee Joint to Sinusoidal Compression: Influence of Fluid Pressurization in Soft Tissues

ASME 2012 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2012-80417 ◽

2012 ◽

Author(s):

Yaghoub Dabiri ◽

LePing Li

Keyword(s):

Knee Joint ◽

Soft Tissues ◽

Mechanical Response ◽

Fluid Pressure ◽

Joint Modeling ◽

Loading Frequency ◽

Human Knee ◽

Human Knee Joint ◽

Fluid Pressurization

The mechanical response of the knee joint has been simulated using finite element methods with elastic material models [1–4]. Fluid pressurization in articular cartilage and menisci has not been considered in the anatomically accurate joint modeling until recently [5–7]. We have recently considered stress relaxation and creep behavior of human knees. The objective of the present study was to investigate the mechanics of the femoral cartilage under cyclical knee compression. We are particularly interested in the determination of loading versus unloading patterns for the fluid pressure and flow, as well as the influence of the loading frequency on the fluid pressurization.

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A new approach to validate a musculo-skeletal human knee joint model

Journal of Biomechanics ◽

10.1016/0021-9290(94)91348-x ◽

1994 ◽

Vol 27 (6) ◽

pp. 806

Author(s):

M. Lamontagne ◽

G. Németh ◽

P. Wretenberg

Keyword(s):

Knee Joint ◽

Joint Model ◽

New Approach ◽

Human Knee ◽

Human Knee Joint

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A Validated Three-Dimensional Computational Model of a Human Knee Joint

Journal of Biomechanical Engineering ◽

10.1115/1.2800871 ◽

1999 ◽

Vol 121 (6) ◽

pp. 657-662 ◽

Cited By ~ 188

Author(s):

G. Li ◽

J. Gil ◽

A. Kanamori ◽

S. L.-Y. Woo

Keyword(s):

Experimental Data ◽

Finite Element ◽

Knee Joint ◽

Three Dimensional ◽

Optimization Procedure ◽

Element Model ◽

Joint Model ◽

Equivalent Resistance ◽

Human Knee ◽

Human Knee Joint

This paper presents a three-dimensional finite element tibio-femoral joint model of a human knee that was validated using experimental data. The geometry of the joint model was obtained from magnetic resonance (MR) images of a cadaveric knee specimen. The same specimen was biomechanically tested using a robotic/universal force-moment sensor (UFS) system and knee kinematic data under anterior-posterior tibial loads (up to 100 N) were obtained. In the finite element model (FEM), cartilage was modeled as an elastic material, ligaments were represented as nonlinear elastic springs, and menisci were simulated by equivalent-resistance springs. Reference lengths (zero-load lengths) of the ligaments and stiffness of the meniscus springs were estimated using an optimization procedure that involved the minimization of the differences between the kinematics predicted by the model and those obtained experimentally. The joint kinematics and in-situ forces in the ligaments in response to axial tibial moments of up to 10 Nm were calculated using the model and were compared with published experimental data on knee specimens. It was also demonstrated that the equivalent-resistance springs representing the menisci are important for accurate calculation of knee kinematics. Thus, the methodology developed in this study can be a valuable tool for further analysis of knee joint function and could serve as a step toward the development of more advanced computational knee models.

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A Numerical Model of Mechanics of Osteoarthritis in Human Knee Joint

Volume 2: Biomedical and Biotechnology ◽

10.1115/imece2012-89225 ◽

2012 ◽

Author(s):

Yaghoub Dabiri ◽

LePing Li

Keyword(s):

Articular Cartilage ◽

Knee Joint ◽

Fluid Pressure ◽

Three Dimensional ◽

Solid Matrix ◽

Joint Mechanics ◽

Human Knee ◽

Human Knee Joint ◽

Contact Loads ◽

Model Fluid

Articular cartilage is composed of water entrapped in a solid matrix formed by proteoglycans and collagen fibers. Therefore, the mechanical behavior of this tissue is determined by all of these three components. In addition, the properties of articular cartilage vary along the depth and by location. In the human knee joint, the three dimensional geometry as well as the contact between the cartilaginous tissues plays essential roles in the joint mechanics. On the other hand, initiation and progression of osteoarthritis (OA) could be partly caused by contact loads. Consequently, the fibrillar and non-fibrillar matrices, the three dimensional geometry and the contact between the tissues should be considered as essential parameters in the study of the mechanics of osteoarthritis. However, previous studies on OA mechanics were mostly limited to explants geometries [1]. Also, the contact mechanics associated with the fluid pressure have not been considered in the previous OA models. In a recent knee model, fluid was considered in femoral cartilage but not in the menisci [2]. Additionally, the depth-dependent mechanical properties were not included in that model.

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