OpenSim User Profile: Katherine Holzbaur, PhD
Katherine Holzbaur of Wake Forest University Medical School simulates the biomechanics of the upper limb.
Katherine Holzbaur, PhD, assistant professor of biomedical engineering at Wake Forest University Medical School, combines computation and experiments to understand how therapeutic interventions can help people with limited upper limb movements, such as the elderly or those with specific neuromuscular disorders. For example, in her postdoctoral work with Wendy Murray, PhD, now at Northwestern University, they looked at the effect of tendon transfer surgery on hand function in people with spinal cord injuries.
For the computational side of her work, Holzbaur now uses OpenSim exclusively. Initially, the program did not include key functionality for upper limb simulation. It couldn’t handle the kinds of complex constraints one finds in the shoulder, for example, where the clavicle and scapula (bones connected to the shoulder’s ball and socket joint) slide past one another, constraining each other’s movements. So Holzbaur worked closely with the Simbios staff when this new functionality was added to OpenSim, testing it in an already validated model of the upper limb. This will be to be useful to other groups as well, she says. “It’s a really important function. Researchers of lower limb function may choose to take advantage of it to have more flexibility in how they describe joint kinematics.”
Using OpenSim, Holzbaur’s team recently generated simulations of upper limb reaching and other movements. The work was presented at the American Society of Biomechanics meeting in August 2009. “We’re still in the development phase but getting to where we can really reliably generate simulations and validate them,” says Holzbaur.
Because models developed in OpenSim can be made freely available, she says, “If we develop our model and publish it, other people can use and access it in a straightforward way without a lot of duplication of effort. People can build off the previous work of other researchers. That makes a big difference.”