The effect of connective tissue material uncertainties on knee joint mechanics under isolated loading conditions

Abstract

Although variability in connective tissue parameters is widely reported and recognized, systematic examination of the effect of such parametric uncertainties on predictions derived from a full anatomical joint model is lacking. As such, a sensitivity analysis was performed to consider the behavior of a three-dimensional, non-linear, finite element knee model with connective tissue material parameters that varied within a given interval. The model included the coupled mechanics of the tibio-femoral and patellofemoral degrees of freedom. Seven primary connective tissues modeled as nonlinear continua, articular cartilages described by a linear elastic model, and menisci modeled as transverse isotropic elastic materials were included. In this study, a multi-factorial global sensitivity analysis is proposed, which can detect the contribution of influential material parameters while maintaining the potential effect of parametric interactions. To illustrate the effect of material uncertainties on model predictions, exemplar loading conditions reported in a number of isolated experimental paradigms were used. Our findings illustrated that the inclusion of material uncertainties in a coupled tibio-femoral and patello-femoral model reveals biomechanical interactions that otherwise would remain unknown. For example, our analysis revealed that the effect of anterior cruciate ligament parameter variations on the patello-femoral kinematic and kinetic response sensitivities were significantly larger, over a range of flexion angles, when compared to variations associated with material parameters of tissues intrinsic to the patello-femoral joint. We argue that the systematic sensitivity framework presented herein will help identify key material uncertainties that merit further research, as well as provide insight on those uncertainties that may not be as relative to a given response.

Computational biodynamics of human knee joint in gait: From muscle forces to cartilage stresses

“…Future simulations of joint disorders (i.e., ligament injuries, cartilage defects and degenerations) justify also the use of the detailed model of the joint. It is to be emphasized that alterations in the input kinematics/kinetics, material and structural properties as well as joint flexion axis considered in this study likely influence the results the extent of which can only be quantified by proper sensitivity analyses (Dhaher et al, 2010;Moglo and Shirazi-Adl, 2005). Predicted activation levels in quadriceps and gastrocnemius muscles are in satisfactory agreement with values in the literature Lin et al, 2010;Neptune et al, 2004;Shelburne et al, 2005;Winby et al, 2009) and follow the same relative trends as measured EMG activities (Astephen, 2007;Astephen et al, 2008b).…”

Probabilistic Approach for Determining the Material Properties of Meniscal AttachmentsIn VivoUsing Magnetic Resonance Imaging and a Finite Element Model

“…Specifically, we believe that our results will be useful not only for establishing diagnoses, but also for surgery in allowing for evaluation of the material properties of a patient's soft tissue in vivo using MRI. In many previous computational studies, MR images have been primarily used to generate intact FE models, followed by validation in cadavers (Haut Donahue et al, 2003;2004;Pena et al, 2006;Baldwin et al, 2009;Dhaher et al, 2010;Kwon et al, 2014). However, we hypothesize that data from evaluation of material properties in vivo using MR images will be useful for both damaged and normal knees.…”

“…Indeed, the majority of previous studies refer to cadaveric or reference data in order to conduct sensitivity or probabilistic analysis (Baldwin et al, 2009;Dhaher et al, 2010). However, there are significant differences between in vivo and in vitro properties.…”

Subject-Specific Finite Element Modeling of the Tibiofemoral Joint Based on CT, Magnetic Resonance Imaging and Dynamic Stereo-Radiography Data in Vivo

“…It has been shown that under this condition, the biphasic response of cartilage can be negligible and the single-phase linear isotropic constitutive law be applicable [40,41]. Therefore, cartilage was modeled as a homogeneous, elastic, linearly isotropic material [1,2,[4][5][6][7]9,16,23,25,30,32,33,[35][36][37][38][39][42][43][44][45][46] with a modulus of 15 MPa [4,9,25,30,35,45] and a Poisson's ratio of 0.46 [31][32][33]47,48].…”

“…The menisci were therefore modeled as linearly elastic, transversely isotropic materials [1,2,4,9,10,16,25,30,[34][35][36]39,[43][44][45]52], where the modulus and Poisson's ratio were 20 MPa and 0.2, respectively, in the radial and axial directions, and 140 MPa and 0.3, respectively, in the circumferential direction [4,30,45,52]. Time dependent effects of the cartilage and menisci properties were not considered due to the quasi-static nature of the models [4,7,8,23,30,32,35,[40][41][42]48,53,54].…”