There isn’t a cure for knee osteoarthritis, the debilitating condition where the joint’s cushioning cartilage wears down. The treatment that has proven most effective for the disease, which causes painful friction between the bones and afflicts almost 14 million people in the United States, is exercise-based physical therapy. But, the problem is, it’s difficult to accurately measure a patient’s improvement outside of a clinical or laboratory setting. Deepak Kumar wants to change that.
An assistant professor of physical therapy, he’s started a new clinical trial to develop wearable sensor technology that can measure patients’ improvement remotely.
“There are devices like the FitBit that measure how many steps a patient is walking every day, but they don’t give us the information we need about the quality of their walking—has their walking pattern changed, are they more symmetric, how much time are they spending on their painful knee versus their nonpainful knee,” says Kumar, who is also the director of Sargent’s Movement & Applied Imaging Lab. “There just isn’t a good way to get that information while the patients are out and about in their everyday life.”
Kumar and his coresearcher Tuhina Neogi, a professor of medicine and chief of rheumatology at Boston Medical Center (BMC), are collaborating with the BU Physical Therapy Center, BMC, Pfizer, and Eli Lilly on the clinical trial.
For the study, participants wear a tiny sensor on their lower back. They’re expected to wear the sensors all day, every day, for five weeklong periods before, during, and after physical therapy treatment, even during activities like sleeping and showering. The sensor has an accelerometer and a gyroscope to capture metrics like the angular velocity of the body. The participants, all age 50 and older and diagnosed with knee osteoarthritis, take part in 18 physical therapy sessions over 12 weeks, with a combination of in-person visits at the BU Physical Therapy Center and virtual sessions.
Kumar says there are many benefits to having a device that measures patients’ improvement outside of a lab setting. “In the lab, we have our patients do certain activities—walking, getting up from a chair—and that might not reflect how they do those activities in their daily life because it’s an artificial environment.”
Kumar, who expects to conclude the study by early 2022, will compare the sensor data to information recorded by 3D optical motion capture—a sophisticated, lab-based system of cameras and sensors used to track movement in detail—to check its accuracy.
“The main goal of this study is to validate the small single sensor against this 3D motion capture, and then use the validated metrics to see if we can detect improvement after physical therapy,” Kumar says. He hopes that these smaller sensors can then be used in future large-scale studies to measure outcomes of physical therapy on osteoarthritis, with the goal of refining treatment.