Probabilistic evaluation of the material properties of the in vivo subject‐specific articular surface using a computational model

Abstract

This article used probabilistic analysis to evaluate material properties of the in vivo subject-specific tibiofemoral (TF) joint model. Sensitivity analysis, based on a Monte Carlo (MC) method, was performed using a subject-specific finite element (FE) model generated from in vivo computed tomography (CT) and magnetic resonance imaging (MRI) data, subjected to two different loading conditions. Specifically, the effects of inherent uncertainty in ligament stiffness, horn attachment stiffness, and articular surface material properties were assessed using multifactorial global sensitivity analysis. The MRI images were taken before and after axial compression, and when the flexion condition had been maintained at up to 90 degree flexion in the subject-specific knee joint. The loading conditions of the probabilistic subject-specific FE model (axial compression and 90 degree flexion) were similar to the MRI acquisition setup. We were able to detect the influence of material parameters while maintaining the potential effect of parametric interactions. Throughout the in silico property optimization, a subject-specific FE model was used and less sensitive parameters were eliminated in the global sensitivity method. Soft tissue material properties were estimated using an optimization procedure that involved the minimization of the differences between the kinematics predicted by the subject-specific model and those obtained through in vivo subject-specific data. The results of this approach suggest that the articular surface mechanical properties could be found by using in vivo measurements, which clarifies the valuable tool for future subject-specific studies related to TF joint scaffolds, allografts and biologics. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1390-1400, 2017.

Measuring the effect of femoral malrotation on knee joint biomechanics for total knee arthroplasty using computational simulation

“…23,24 The contours of the bony structures (including the femur, tibia, fibula, and patella) and the soft tissues (the ligaments and menisci) were reconstructed from the CT and MRI images, respectively. This computational knee joint model has been established and validated in previous studies.…”

“…The coefficient of friction between the PE material and metal was chosen to be 0.04 for consistency with previous explicit FE models. 24,29 Contact was defined using a penalty-based method with a weighting factor. As a result, contact forces were defined as a function of the penetration distance of the master into the slave surface.…”

“…The PE insert and patellar button were modelled as an elastoplastic material (Table II). 24 The femoral and tibial components were fully bonded to the femur and tibia bone models, respectively. All implant components were modelled as linear elastic isotropic materials (Table II).…”

Biomechanical effect of a lateral hinge fracture for a medial opening wedge high tibial osteotomy: finite element study

“…An existing, previously validated, finite element (FE) model for the knee joint was used in this study [24][25][26]. Radiographic data from the knee joint of a 36-year-old male weighing 80 kg and 178 cm in height were acquired using computed tomography (CT) and magnetic resonance imaging (MRI).…”

“…Details of the element type and numbers are provided in Table 1 [35]. The medial opening wedge HTO was simulated such that the loading axis of mechanical axis became lateral at 62.5%, as suggested by Fujisawa et al [26] (Fig. 3).…”