Each year, up to half a million Americans tear an anterior cruciate ligament, or ACL, one of four strong cords of connective tissue important for stabilizing the knee. Many have the torn ligament replaced with a graft – a common procedure referred to as ACL reconstruction. While reconstruction generally allows the person to return to normal activity, it doesn’t prevent the long-term effects of a joint injury: osteoarthritis.

“Some reports suggest rates of OA as high as 80 percent at 14 years out from ACL surgery,” says Martha Murray, MD, orthopaedic surgeon at Children’s Hospital Boston. Injuring your ACL when you are young, as if often the case, can translate to a lot of years with osteoarthritis, she says. 

Joint injuries – including ACL tears – are a common cause of osteoarthritis that scientists say can be prevented. Researchers are looking at ways to prevent injuries as well as better ways of treating them. The results of their research could potentially lead to ways to prevent OA of the knee as well as other joints following an injury.

Injury Prevention
Research into the prevention of ACL injuries in recent years has focused largely on why certain groups – particularly young women – are at high risk. “Right now, the general prevailing thought is that it is potentially due to altered movement patterns and poor neuromuscular control,” says Darin Padua, PhD, associate professor in the Department of Exercise and Sport Science at the University of North Carolina, Chapel Hill.  

While women tend to be more likely to display these patterns, Padua suspects the same factors also apply to men. When it comes to total numbers, men have more ACL injuries than women. And regardless of your sex or age when an injury occurs, the result – damage leading to osteoarthritis – can be the same.

“The good thing is that prevention programs seem to pretty effective,” he says. Programs of specially designed exercises, when performed regularly, have been shown to reduce ACL injuries in people involved in sports such as soccer, basketball, volleyball, lacrosse or snow skiing that involve stopping very quickly and changing direction or landing from a jump.

Prevention programs begin with dynamic stretching, followed by light strengthening of key muscles around the hip region, balance exercises and agility or biometric exercises, Padua says. 

“That sounds like a lot, but it can all be done within a 10- to 15- minute window once you have learned how to do them properly,” he says. If everyone committed to 10 to 15 minutes of exercises about three times a week, he would anticipate seeing a 50 percent reduction in ACL injuries overall, he says.

The exercises are also important for anyone who has had an ACL injury in the past, because research shows that having one ACL injury increases your risk of a second injury (on the same knee or the other one) up to 10 times, says Padua.

“It has yet to be seen if [the exercises] reduce the early onset of osteoarthritis but from a purely theoretical standpoint, it would make sense they would be effective at doing that,” says Padua.

The next steps involve refining the programs to make them as simple and efficient as possible and looking at ways to increase awareness so that people who need them, do them and do them properly.