OpenSim User Profile: B.J. Fregly, PhD

University of Florida’s B.J. Fregly hopes to use OpenSim to simulate the knee.



B.J. Fregly, PhD, associate professor of mechanical and aerospace engineering and of biomedical engineering at the University of Florida, uses computational biomechanics to simulate treatments for knee osteoarthritis and wear performance of knee replacements. He is looking forward to the release of OpenSim 2.0 (expected out in October), which he says “will be the first OpenSim release to meet the specific research needs I have.”


OpenSim 2.0 will let users, for the first time, create user-defined loads in musculoskeletal models. For Fregly, this means he can define contact loads between bones such as the femur and the tibia, which interact with each other within the knee. Contact forces play a critical role in osteoarthritis and wear, Fregly says. “Contact is essential to what we do.” OpenSim 2.0 will also be more flexible, allowing users to define their own optimization performance criteria, “which will expand the utility of OpenSim,” he says.


Fregly has attended several OpenSim training sessions, and in October, he plans to bring his contact models to Stanford and tie them into an OpenSim musculoskeletal model of the knee. “OpenSim is a big timesaver if you want to make a complicated musculoskeletal model,” he says. “So I’m looking forward to using it for that purpose.” He also plans to use OpenSim for teaching his undergraduate biomechanics students. “They can put it on their PCs, build realistic musculoskeletal models, and perform realistic movement simulations quickly and easily. I think OpenSim will be a great tool to help them learn.” And, as these students go on to graduate school or industry and take this experience with them, he predicts that “OpenSim will become a standard for musculoskeletal modeling.”


“Simbios is making commercial grade software as part of an NIH project, and I think that’s awesome,” Fregly concludes. “People are going to use it. It’s just a question of time before it gets them over the bar for a particular need.  Hopefully for me, version 2.0 will get me over the bar.”   

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