Sensitivity of the tibio-femoral response to finite element modeling parameters

Abstract

A generic finite element (FE) model of the lower limb was used to study the knee response in-vivo during a one-legged hop. The approach uses an explicit FE code and a combination of estimated muscle forces and measured three-dimensional tibio-femoral kinematics and ground reaction force as input to the FE model. The sensitivity of the simulated tibio-femoral response to variations of key geometric and material parameters was investigated by performing a total of 38 different simulations. The amplitudes of both kinematic and kinetic responses were affected by the change of these parameters. For the current approach, the results suggest that while cartilage mechanical and geometric properties are very important for the estimation of tibio-femoral cartilage pressure, they have limited effects on the overall kinematic response. The study may help to better define the relative importance of modeling parameters for the development of subject-specific models.

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

“…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]. The anterior and posterior meniscal roots for each meniscus were modeled as linear springs with spring constants of 2000 N/mm [9,23,25,30,35,36,45,52].…”

“…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].…”

“…Two FEM studies have employed advanced imaging techniques to acquire skeletal kinematics: Beillas et al [7,8] used X-ray imaging that required surgical implantation of radio-opaque markers into the bone; Yao et al [16] utilized a loading device to exert a force on the knee as it was undergoing magnetic resonance imaging (MRI) in a supine position. While these studies were successful attempts to incorporate task-specific [7,8] or load-specific [16] kinematics, quantitative verification of their FE model predictions was not conducted. Validation or verification is a crucial step before making interpretations based on model predictions or using the model for clinical applications [17,18].…”

“…Studies have incorporated skeletal kinematics from either nonsubject-specific data [6][7][8] or skin surface marker measurements [9,10]-the latter are prone to soft-tissue artifacts [11] due to marker movement [12,13] and inaccurate marker positioning on the skin relative to the bone [14,15]. Two FEM studies have employed advanced imaging techniques to acquire skeletal kinematics: Beillas et al [7,8] used X-ray imaging that required surgical implantation of radio-opaque markers into the bone; Yao et al [16] utilized a loading device to exert a force on the knee as it was undergoing magnetic resonance imaging (MRI) in a supine position. While these studies were successful attempts to incorporate task-specific [7,8] or load-specific [16] kinematics, quantitative verification of their FE model predictions was not conducted.…”

A review of probabilistic analysis in orthopaedic biomechanics

“…see references [61] to [63]). Other experimental [64][65][66] and computational [62] studies have shown that varying ligament attachment site locations by as little as 2 mm affected joint kinematics. Due to the expensive computational cost of exploring all combinations and levels of input parameter variations, constraint sensitivity predictions typically involved discrete changes in ligament input parameters (stiffness) and were focused on the cruciate ligaments under specific loading scenarios.…”