, Jackie Whittaker, PT, PhD, said at the World Congress of Osteoarthritis.
“We all know that the burden of this disease is enormous and it’s expanding at an alarming rate,” she said at the congress, sponsored by the Osteoarthritis Research Society International.
“The only way that we have at this moment to try to reduce the burden of this disease is to shift our approach to management upstream and focus on prevention,” said Dr. Whittaker, who is an associate professor and research director at the University of Alberta, Edmonton, Canada.
According to the World Health Organization, OA is expected to become the fourth leading cause of disability worldwide by 2020. Furthermore, there will be a projected rise in prevalence from 12% to 25% in North America by 2030.
Dr. Whittaker suggested that it was time to try to identify those at risk of developing OA, such as after a joint injury, and ran through some suggestions on how posttraumatic OA (PTOA) might be preventable.
Secondary prevention of posttraumatic osteoarthritis
The prevention of PTOA can be split into primary, secondary and tertiary prevention, with primary prevention trying to prevent injuries from occurring in the first place.
“Strategies aimed at identifying and slowing down the onset of symptomatic osteoarthritis in preclinical populations would be referred to as secondary prevention,” Dr. Whittaker explained, adding that tertiary prevention would then be strategies aimed at improving function and reducing disability in those who already have symptomatic PTOA.
While there are programs that address primary and tertiary prevention – such as Footy First, an exercise training program adopted by the Australian Football League to reduce the risk of common leg injuries and the Good Life with osteoArthritis in Denmark (GLA:D®) education and supervised exercise program for those with symptomatic OA – there is more of a gap for secondary prevention.
Some of the first steps to developing a secondary prevention model would be to determine the extent of PTOA after joint injury and then identify risk factors or causal mechanisms. Then, prevention strategies could be developed and tested before implementation and effectiveness studies are performed.
Performing the necessary prospective cohort studies, however, is when things get challenging – PTOA can take 10–15 years to manifest and studies would potentially need to run for long periods of time, which comes at a cost. Other challenges are that there is no commonly agree definition. PTOA is multifactorial, and because people may be in their 20s, there could be other contributing factors to the disease course.
Identifying modifiable risk factors
There are a “fair number” of prospective and retrospective studies that have been done to try to identify patients at risk for OA after joint injury. Several have looked at unmodifiable risk factors, such as age and sex, and the type of injury. Others have looked at potentially modifiable factors such as the treatment approach and avoiding re-injury, joint mechanics and strength, body composition and aerobic fitness and behavioral characteristics such as physical activity and return to sport.
Data from the Alberta Youth PrE-OA Study, an ongoing longitudinal cohort study, have shown that structural changes consistent with OA are not unique to tears in the anterior cruciate ligament or to meniscal tears, which are known to up the risk of PTOA. Furthermore, the odds of having MRI-defined OA 3–10 years after a knee injury varies by the injury history, type, and surgery.
Other findings from the Alberta Youth PrE-OA Study data have shown that previously injured subjects have a 30% risk for re-injury, with weaker knee extensors and flexors and poorer dynamic balance than uninjured study participants. The results have also shown that there is reduced physical activity and avoidance in those who have been injured.
Who is the population at risk?
“Although the supporting evidence and the level of evidence for some of the risk factors is not as thorough as we would like it, there are some common themes across the literature, that are consistent to what we see in clinical practice, and what we know from primary and tertiary prevention,” Dr. Whittaker said. “Based upon that, we can start to hypothesize who’s at greatest risk of developing posttraumatic osteoarthritis and what we might start doing about it right now.”
Dr. Whittaker proposed the following risk factors could be used to “build a profile” of someone at risk of PTOA:
- Having sustained an anterior cruciate ligament (ACL) tear with or without a damaged meniscus
- Elevated body mass index (BMI) or adiposity, and low grade systemic inflammation
- Weak knee muscles, and poor dynamic balance
- Reduced or disengaged from physical activity
- Insufficient rehabilitation, pain or stiffness, or fear of movement