About one out of every five patients who undergo a total knee replacement are not satisfied with the outcome of the operation, often because they continue to experience pain, stiffness and functional limitations.
Josh Roth believes that a one-size-fits-all approach to operations such as total knee replacement is a key source of this low rate of satisfaction. In his new role as an assistant professor of mechanical engineering, he aims to help improve patient satisfaction by developing personalized treatments for injuries and diseases affecting the joints and the tissues that make up joints.
Roth, who joined the faculty in July 2019, says many orthopedic procedures today are not specifically tailored for an individual patient. Instead, surgeons often apply the same general guidelines to every patient—largely because they lack sufficient biomechanical data to guide their decisions and inform personalized treatments.
“One of the big pushes of my research group is to develop tools to help surgeons and enhance their decision making,” he says. “Aided by these tools, we want to generate algorithms to develop personalized treatments for different diseases.”
One tool Roth is currently working on is a sensor that can measure the tension in an individual ligament, which is the structure that attaches bones to bones to provide stability to a joint. Once it’s developed, Roth plans to use this sensor to collect data from actual patients—measuring both healthy patients and those undergoing orthopedic treatments. Then he can identify which patients responded well or poorly to the treatment and analyze the data to better understand how different ligament tensions can affect patient satisfaction following a procedure.
Roth’s background is in studying total knee replacement procedures, and his current research focuses mainly on the knee. He’s also interested in helping clinicians develop some earlier interventions for osteoarthritis of the knee before it becomes severe enough to require total knee replacement.
“My goal is to understand the patient’s current disease state and then use computational models to figure out what kind of less invasive treatment might help delay or slow down that patient’s disease progression,” he says.
There’s a big need for personalized treatments in orthopedic medicine, Roth says, because the current one-size-fits-all approach doesn’t account for significant variability between patients. For example, some patients are naturally bow-legged or knock-kneed. But the traditional guideline surgeons follow for a total knee replacement is to make a patient’s leg form a straight line from the hip to the knee and ankle.
“The problem is, if you try to put every patient undergoing a procedure back to some average of the population, there are a lot of people for which you will be fundamentally changing the way that their joint functions,” he says. “But if we had a different approach that’s personalized to the patient, we might be able to improve outcomes and patient satisfaction.”
Roth earned his bachelor’s degree in mechanical engineering from California Polytechnic State University in 2009. He went on to earn a master’s degree and PhD in biomedical engineering from the University of California, Davis, in 2014 and 2016. During graduate school, his research on knee replacement treatments gave him the opportunity to work closely with clinicians, and he was excited to see how his research could make a difference in the lives of real patients.
Roth says Mechanical Engineering Professor Darryl Thelen’s reputation as an outstanding mentor attracted him to UW-Madison, and in 2016 he began working as a postdoctoral scholar in Thelen’s research group. Roth, who had been living in California for many years, ended up falling in love with Madison and the university.
“I really like that there’s a strong group of biomechanics researchers with diverse backgrounds in the mechanical engineering department at UW-Madison,” he says. “It’s a tight-knit community where the researchers support each other, which also benefits the students.”
Roth holds a dual faculty appointment with the Department of Orthopedics and Rehabilitation in the University of Wisconsin School of Medicine and Public Health, and he says that opportunity was a big draw for him joining the UW-Madison faculty.
“These kinds of positions are fairly rare, and it’s very appealing to me to be able to work with colleagues in the mechanical engineering department and then also have close ties with clinicians in the Department of Orthopedics and Rehabilitation to impact human health,” he says.
Author: Adam Malecek