Michael Albro (right), an ENG assistant professor of mechanical engineering, and postdoctoral researcher Masumeh Kazemi using the Raman needle probe on an excised bovine cartilage specimen.

Osteoarthritis

New Noninvasive Light-Based Device Could Help Diagnose Osteoarthritis Early

Knee and other joint cartilage health could be assessed with click of a button; may help prevent further damage—and painful joint replacement surgery

It’s a disease that causes pain, can’t be cured right now, and can’t be diagnosed until it’s too late. Osteoarthritis afflicts 32.5 million Americans, making it the most common type of arthritis, according to the Centers for Disease Control and Prevention. A degenerative joint disease, it occurs when articular cartilage—the tissue that cushions the ends of bones at the joint—wears away. It leads to pains and aches and even disability. The tissue loss is irreversible, so eventually an artificial joint is required. That’s a problem when the sufferer is a young adult or a teenager, because artificial joints last for only a couple of decades.

“When you think of osteoarthritis, you think of older individuals, but the reality is that 24 percent of adults are afflicted with osteoarthritis,” says Boston University orthopedics researcher Michael Albro. “The burden can at times fall even heavier on younger patients.”

Every year, hundreds of thousands of adolescents and young adults suffer sports injuries that can lead to post-traumatic osteoarthritis, says Albro, a BU College of Engineering assistant professor of mechanical engineering. “And they’re not yet eligible for a joint replacement procedure.”

Albro is leading a team of BU researchers—along with clinicians and other experts around the world—developing a groundbreaking weapon in the fight against osteoarthritis. Their noninvasive light-based arthroscope, which uses a technique called Raman spectroscopy, could be used to gauge the health of cartilage in the knees and other joints with the click of a button. The work recently received a $3 million boost from the National Institutes of Health.

“We keep getting contacted by orthopedic surgeons in the area who really want to use this in the clinic as soon as possible,” says Albro, who’s also affiliated with the BU Photonics Center. “This NIH grant will essentially enable us to prove that Raman diagnostic measurements can outperform MRI.”

Dating Fossils, Busting Art Forgers, and Now Saving Knees?

Soft tissue doesn’t show up very well in radiography scans, and MRI—the gold standard for fractures and other diagnoses—doesn’t have quite the granular resolution needed for imaging cartilage. That means no method currently in use can detect osteoarthritis early, when there might still be time to intervene.

The alternative that Albro and colleagues have crafted uses the principle of Raman scattering. Long used to date fossils and bust art forgers, a Raman spectroscope shines light on a specimen, counts the tiny number of light particles that undergo a shift in wavelength, and uses that data to assess the specimen’s chemical composition.

Applying this process to articular cartilage, Albro’s team figured out that Raman scattering would pick up on key biomarkers, measuring the tissue’s composition and mechanical function. With a grant from the Arthritis Foundation, they successfully tested their device—the first-ever Raman arthroscope—on donor cartilage in 2021. Now, with the NIH grant, they are testing it in live large animal models, bringing the technology another step closer to the clinic.

Why build a better arthroscope if cartilage loss can’t be reversed? Two good reasons, says Albro. First, many scientists are in fact working on methods that might stop osteoarthritis in its tracks—and some even hope to reverse it—so if the disease could be detected early enough, that would prevent a lot of damage from ever occurring.

Second, many researchers are working on engineering or regenerating tissue to replace the cartilage. Indeed, Albro and many of his colleagues on the Raman arthroscope project are also involved in such efforts, as part of a two-pronged approach. Their arthroscope can take what they call an “optical biopsy,” which can be used to assess the quality of the replacement tissue that they and others engineer, just as well as it can assess natural tissue.

“Ultimately, one of the key benefits of the [Raman] technology is going to be, for the first time ever, to examine the efficacy of some of these exciting emerging therapies,” says Albro.

“That’s the main utility of this whole coordinated effort,” says Brian Snyder, one of Albro’s collaborators. An ENG research professor of biomedical engineering, he’s also an orthopedic surgeon at Boston Children’s Hospital. “We’re developing the diagnostic tools, as well as minimally invasive interventions to repair the tissue. My partners in sports medicine at Children’s are anxious to start using [the Raman arthroscope] immediately.”

Others working on the project include Mark Grinstaff, BU’s Distinguished Professor of Translational Research and a William Fairfield Warren Distinguished Professor, and biophotonics expert Mads Bergholt from King’s College London, United Kingdom—as well as “just terrific, talented students” from across ENG, says Albro.

“These are challenging problems that any one of us sitting alone would really not be able to tackle,” he says. “These international interdisciplinary collaborations are wonderful—but they can also be precarious, given the distance and everyone’s busy schedules. So, the magic formula is, you have to really like working together. And we seem to have found this really nice team that’s just enthusiastic to work together on these projects.”