A Subject-Specific Framework to Inform Musculoskeletal Modeling: Outcomes from the IUPS Physiome Project

Abstract

The International Union of Physiological Sciences (IUPS) Physiome Project was established as a framework for creation, sharing and dissemination of multiscale mathematical models of human physiology. We present a suite of subject-specific musculoskeletal models that were developed using this framework. This process starts with subject-specific geometry development using high-order cubic Hermite elements suitable for describing the topology of complex musculoskeletal structures accurately. These geometries are able to be customized using free-form deformation techniques with data from Computed Tomography (CT), Magnetic Resonance Imaging (MRI) or anthropometric information derived from motion capture. We describe how the deformations of soft tissues are referred to a microstructural curvilinear coordinate system. The constitutive laws that describe the stress-strain behavior of soft tissue are also referred to this anatomically based material coordinate system. Finally, we highlight the finite deformation mechanics framework through a set of clinically relevant examples. These examples include the efficient creation of a subject’s hip model from CT for implant testing with validation; customization of bone and muscle geometry; a hybrid free-form deformation and mechanics method for assessing gait; coupled blood flow and solid deformation of the lower limb to examine the influence of deep vein thrombosis and patellofemoral joint contact pressure following a vastus release and tibial medialization.