The challenge of an ACL tear is twofold. There’s the immediate surgery and yearlong rehab that’s plainly visible when an elite athlete is stricken, but research has shown that roughly half of patients suffer persisting problems in the knee years after the original injury.
“What you don’t often see is that, about a decade later, they start to develop signs of osteoarthritis in that joint. By that time, they’re not household names necessarily anymore,” Michael Zabala, an assistant professor in mechanical engineering at Auburn, said, adding: “The reality is that the physician that treats your initial injury is probably not going to be the physician that treats your long-term osteoarthritis. There’s another source of disconnect that makes it difficult.”
Zabala began pursuing biomechanical prevention research while writing his Ph.D. dissertation at Stanford and in the past year has begun using Vicon motion-capture cameras for a comprehensive research project with university athletes, focusing on women’s soccer and basketball where the incidence of prevalence is high (and, recently, including those playing those sports at the club level to increase the research population).
One study found that, among female soccer players with an ACL tear, 51 percent had osteoarthritis problems 12 years later — at a mean age of just 31. By another measure, those with ACL injuries are seven-to-eight times more likely to endure an onset of post-traumatic osteoarthritis.
The research at Auburn begins with an intake evaluation to establish a baseline for each athlete, who undergoes a comprehensive motion analysis of 30 exercises that include walking, jogging, balance tests, jumping in place and sport-specific maneuvers like running and cutting to check joint alignment. The screening is done in a 30-foot-by-32-foot enclosure with 10 of Vicon’s Vantage V5 high-speed cameras — seven hoisted to a height of eight feet and three at waist level — and in conjunction with embedded force plates made by AMTI.
Zabala has indicated some promising early returns about identifying risky joint alignment, although he cautions that the research remains in early stages. One athlete in the study has suffered an ACL injury, offering additional information about a comparison with post-reconstruction biomechanics.
“It’s one thing to be able to measure someone’s knee alignment in the biomechanics lab where you’ve got fancy equipment, but what we want to do is be able to provide indicators of what to look for among, say, the training staff or how to make corrections and improve performance, if you will,” Zabala said.
There are two other prongs to the research, including MRI exams to look for other structural issues in the knee and a blood test. The latter is informed by research from Lt. Col. Steven Svoboda, an M.D. at West Point who found that certain levels of blood-borne biomarkers of collagen turnover correlate strongly with later ACL rupture. (Ligaments are made of collagen.)
The technology powering the motion-capture portion of the study has had some unexpected influences. Vicon’s head of product management, Derek Potter, said that a little more than half of the company’s business stems from the life sciences division — mostly universities and hospitals conducing research — while a quarter comes from engineering firms and a quarter from the entertainment sector, where movies and video games often use the cameras.
Get The Latest Sports Tech News In Your Inbox!
In fact, Potter said, longtime customer Electronic Arts recently installed a 75-camera system in its Vancouver facility. Ubisoft games and The Avengers movies relied on Vicon cameras as well, with innovations across the varying fields helping improve the technology and the techniques in the others.
“You might not think that there’d be all that much connection between what a video game company does and what a researcher studying ACL [injury] prevention really does, but the truth is that every little thing that someone using our system for video games does, they do things to improve tracking and make the tracking of the markers a little bit better,” Potter said.
“Some of the innovations that we get from entertainment and engineering find their way over into sports biomechanics and provide a lot of benefit over there, and the converse is true as well.”