A subject-specific integrative biomechanical framework of the pelvis for gait analysis

Abstract

Analysis of the human locomotor system using rigid-body musculoskeletal models has increased in the biomechanical community with the objective of studying muscle activations of different movements. Simultaneously, the finite element method has emerged as a complementary approach for analyzing the mechanical behavior of tissues. This study presents an integrative biomechanical framework for gait analysis by linking a musculoskeletal model and a subject-specific finite element model of the pelvis. To investigate its performance, a convergence study was performed and its sensitivity to the use of non-subject-specific material properties was studied. The total hip joint force estimated by the rigid musculoskeletal model and by the finite element model showed good agreement, suggesting that the integrative approach estimates adequately (in shape and magnitude) the hip total contact force. Previous studies found movements of up to 1.4 mm in the anterior-posterior direction, for single leg stance. These results are comparable with the displacement values found in this study: 0-0.5 mm in the sagittal axis. Maximum von Mises stress values of approximately 17 MPa were found in the pelvic bone. Comparing this results with a previous study of our group, the new findings show that the introduction of muscular boundary conditions and the flexion-extension movement of the hip reduce the regions of high stress and distributes more uniformly the stress across the pelvic bone. Thus, it is thought that muscle force has a relevant impact in reducing stresses in pelvic bone during walking of the finite element model proposed in this study. Future work will focus on including other deformable structures, such as the femur and the tibia, and subject-specific material properties.

An Integrated Method of Biomechanics Modeling for Pelvic Bone and Surrounding Soft Tissues

“…A limited range of motion in the sacroiliac joint can cause significant stress and strain deviations in FE analysis [ 28 , 33 ]. Due to its strong kinematic capability, the hip joint is typically treated as a contact with a small or frictionless coefficient [ 54 , 55 ].…”

“…However, this modeling method, based on anatomical measurements, is difficult to apply for the biomechanical analysis of the pelvis in vivo or in specific objects. Therefore, Watson and Ravera utilized the AnyBody (AnyBody Technology, Aalborg, Denmark) and OpenSim (Stanford University, Stanford, CA, USA) software to compute the muscle force of a muscle-skeleton model using the Hill-type model through the use of inverse kinematics and inverse dynamics tools [ 28 , 54 ]. They combined the positional data collected by the optical motion capture device and the mechanical data collected by the mechanical sensors and then loaded them into the FE model.…”

“…According to related research [ 29 , 34 , 52 , 53 , 54 , 55 ], the sacroiliac and acetabular joints are mobile joints without frictional connections, allowing for natural flexion and extension movements.…”

Determination of the Modulus of Elasticity by Bending Tests of Specimens with Nonuniform Cross Section

“…These contributions are schematically represented in Fig. 2 and may be summed according to equation (4).…”

“…In medical practice and research, numerical simulations of the mechanical behavior of human organs are of increasing interest; for example, finite element simulations of the buildup of stresses in the human pelvis [1][2][3][4]. Reliable experimental identification of relevant material properties is an important precondition to achieve appropriate simulation results.…”