PI: Thelen, Darryl G., Negrut, Dan, and Dhaher, Yasin Proposal Number: 0966535 & 0966742
Individuals who experience knee ligament injuries are at high risk for early onset osteoarthritis, which can result in chronic pain and loss of function. It is believed that biomechanical factors may contribute to such long term problems, with abnormal cartilage loading inducing secondary micro-trauma and joint degeneration processes. The goal of this study is to establish a validated computational framework that would be used to investigate how injury (e.g. partial or full ligament tears), surgical (e.g. ligament reattachment sites, soft tissue tensioning) and rehabilitative (e.g. stretching, muscle re-training) factors can alter tissue loading during movement. Two research aims focus technical effort to meet the stated goal.
The first aim involves the construction of subject-specific, finite element (FE) knee models from high resolution medical images. The FE models include continuum descriptions of connective tissues, and uniquely account for interactions between the tibio-femoral and patella-femoral joints. The second aim investigates a computational approach for predicting knee kinematics, ligament strains and cartilage loading during movement. A co-simulation framework is proposed in which finite element models are solved simultaneously with multi-body and musculo-tendon dynamics, thereby accounting for inherent interactions that exist between knee mechanics and movement dynamics. Bayesian analysis techniques will be used to both statistically calibrate and validate the computational models by comparing model predictions to in vivo measures obtained using dynamic magnetic resonance imaging.
The outreach objectives are to: 1) educate medical practitioners about the inherent coupling between movement and internal joint mechanics that arise naturally during functional tasks, 2) engage minority high school students from Wisconsin and Illinois in Computational Science related activities. The research/education integration plan involves the development of case studies for the physiatry residency program at the Rehabilitation Institute of Chicago (RIC). By relying on the predictive simulation capability developed under this project, these studies will illustrate the importance of considering biomechanical factors when planning clinical interventions that address musculoskeletal injury and diseases. The high school outreach effort will involve a two tier approach that each year will (a) start by organizing seminars that popularize computational science, and (b) follow up by a one week residential summer program at the University of Wisconsin-Madison. The program, ?Promoting the Computational Science Initiative? (ProCSI), is aimed at under-represented high-school students.
The intellectual merit of this study stems from combining advanced computational science, biomechanical modeling and statistical analysis techniques to establish a new computational framework for simulating musculoskeletal function. Broader impact will be achieved by promoting the use of biomechanical modeling to scientifically evaluate the clinical treatment of musculoskeletal injuries, and also by providing under-represented students an opportunity to use computational tools to address meaningful medical problems.
The objective of this project was to develop computer models to investigate cartilage loading during human movement. The public health relevance is that cartilage loading is a key parameter affecting tissue health, with excessive loading potentially contributing to the development of painful knee osteoarthritis. A major outcome of the project was the development and use of a detailed computer model of the human that includes descriptions of the major ligaments and cartilage geometry. We also implemented computer algorithms that allowed us to simulate how the knee would behave during locomotion tasks such as walking and running. The model predictions of internal knee loads agreed very well with measurements taken using an instrumented total joint replacement. The accuracy of these model predictions resulted in our research team being awarded first place in a NIH sponsored competition on knee model development. The knee model is now being used to assess how ligament reconstruction procedures can alter the behavior of the human knee. Such information can enhance physicians’ understanding of clinical outcomes, and may be used to improve knee surgical procedures in a way that diminishes the long-term risk for knee osteoarthritis. We are in the process of sharing our computer models and algorithms with other researchers interested in investigating other clinical procedures used to treat knee pathologies. Outreach activities involved the development of biomechanics exhibits suitable for engaging the interest of elementary, middle school and high school students. We developed a set of activities in which students could take measurements of muscle, force and movement during simple tasks such as running and jumping. All measurements were taken with low-cost, readily available equipment such as video game cameras, smartphones and balance boards. Measurements were shown to the students and used to demonstrate the relationship between basic physics principles and human movement performance. These activities were highly successful in capturing the instinctive interest of students in movement and sports, which may thereby enhance their appreciation and interest in science, technology and math courses.
