In 1988, Steven Svoboda was an offensive guard for the U.S. Military Academy at West Point. During the first kickoff return of a game against Colgate University, he was charging up field to get into position so he could block for the ball carrier. As he turned to look for the player he was supposed to block, Svoboda realized that the player had already passed him; any hit now would be on the player’s back (a “no-no” in football). As Svoboda tried in a split second to reorient himself, he hit the ground with everything about his body position wrong.

“I planted my foot and a blow torch went off in the back of my knee,” says Svoboda remembering that moment.

Svoboda had torn his anterior cruciate ligament, or ACL, the major ligament that stabilizes the knee joint when twisting, cutting or pivoting. The injury ended his football career but inspired him to choose orthopedic surgery with a specialty in sports medicine. Today Lieutenant Steven Svoboda is one of several orthopedic surgeons at West Point tending cadets with ACL tears and other athletic injuries.

The sports universe revolves around torn ACL tears, because they are so common an injury. Reconstructing a torn ACL – a technique less available in Svoboda’s day – helps athletes return to their sport. Such surgeries, though, may not save the joint from osteoarthritis (OA). In fact, people who have sustained an ACL tear seem to get post-traumatic osteoarthritis as early as 10 years after the injury.  

Such a predictable timeframe is giving arthritis researchers a molecular peek into the earliest progression of the disease. Osteoarthritis takes decades to develop. By the time people experience pain in their joints, OA has already advanced to a late stage.

For now, physicians diagnose arthritis using X-rays, which are not sensitive enough to find the disease as it first develops. Svoboda and others in the OA community would like to diagnose OA before changes in the joint occur.

To do so, the researchers need biomarkers – biological materials used to track the progress of a disease. Biomarkers in the blood would allow arthritis researchers the opportunity to stalk OA long before the disease could be detected by any other means. Such an opportunity will help scientists find a drug that may prevent OA. For now though, no osteoarthritis biomarkers are available.

There are some biomarkers that track what’s called cartilage turnover. After an injury cartilage breaks down and builds up again, while such biomarkers aren’t the perfect way to look for predictors of OA, Svoboda decided they’re a good place to start. He designed an experiment using biomarkers that track cartilage turnover to see whether the levels of these molecules changed after ACL injuries.

As it happens, the cadets at West Point are a perfect study group for researchers like Svoboda. Their ages and fitness levels are similar; they’re evaluated medically from the get-go and their health care is provided by the hospital and physicians on the post. Also each class has about 1,000 cadets. When the 45 or so cadets tear an ACL each year, they see either Svoboda or one of his colleagues, so the injuries are easy to track. Because cadets have blood drawn and stored at predictable timeframes, any changes in biomarker levels would be easy to follow.

All cadets at West Point engage in contact sports and rigorous physical training. These activities are also well tracked so Svoboda would have an idea of how often cadets are exposed to physical activity. The interval between injury and ACL surgery is short at West Point because the physical demands of cadets require a fully functioning knee joint. Following post-surgical changes in biomarkers would be possible.

Svoboda realized something else about the cadets: The Army takes lots of blood samples from all recruits beginning when they sign up. The samples are mostly for HIV testing. Since 1985, all Army blood samples have been saved in a repository at the Walter Reed Army Institute of Research in Silver Spring, Md. To date, more than 50 million specimens have been collected and stored.

These are important considerations when researchers use patients to study a disease. The more information available (like regular blood samples), and the more similar the study population in lifestyle, the more scientists can trust study results.

Finding cadets who had torn an ACL was easy; Svoboda used a group already signed up for a clinical trail that compared repair techniques for the surgery. He then found uninjured controls matched for age, sex, height and weight in the Silver Spring repository.

Svoboda analyzed serum samples for four biomarkers that would show whether cartilage – the squishy material that lines all joints – had been formed or broken down. He and his colleagues found changes over time in the ACL group in all of the biomarkers measured.

“No one has ever looked at biomarkers like this so it’s an early study to test the possibility that markers of cartilage turnover may predict people at risk of ACL injuries, and thus osteoarthritis,” says Svoboda. Right now, he says, the study is generating many questions, which he hopes to answer with additional research.

Indeed, this was the first study to follow changes using biomarkers for cartilage turnover in patients who’ve sustained an ACL injury. In 2010, Svoboda won an Arthritis Foundation Young Investigators Award for the work from the OA Biomarker Global Initiative.