Changes in Serum Biomarkers of Cartilage Turnover After Anterior Cruciate Ligament Injury
Svoboda SJ, Harvey TM, Owens BD, Brechue WF, Tarwater PM, & Cameron KL. American Journal of Sports Medicine. 2013; Epub ahead of print. doi:10.1177/0363546513494180
Take Home Message: While young physically-active cadets experience biochemical changes that reflect cartilage turnover during a four-year period, a cadet with an ACL injury may have more pronounced changes. These changes may provide insight for detecting individuals at risk for OA and developing interventions to prevent this.
Knee injuries, such as anterior cruciate ligament (ACL) and meniscus injuries, are very common in athletic and physically-active populations and may increase the risk of osteoarthritis (OA). Biochemical changes after a knee injury may provide insight into the onset of OA, allowing for earlier diagnosis and potential intervention. The authors of this case-control study compared biochemical markers before and after an ACL injury among a group of 45 cadets or active-duty military personnel and compared this injured group with 45 healthy controls (matched to the injured group by age, sex, height, and weight). Both groups had blood collected when they entered the United States Military Academy and at graduation (~4 years later). On average, the ACL injury occurred ~2 years after entering the academy (2 years before graduation). The authors analyzed four markers of cartilage synthesis and degradation. Approximately 87% of participants were male (mean age = 20) and 13% were female (mean age = 19). Overall both groups tended to have lower levels of biochemical markers of cartilage degradation and synthesis at graduation compared with baseline; however, a knee with an ACL injury may be more likely to have biochemical changes that are reflective of cartilage turnover.
This study demonstrated that an individual who suffers an ACL injury will have biochemical changes over time and that these changes may be greater than those in a healthy control. These changes may provide insight as to why ACL-injured participants are at risk for OA. The average time between injury and follow-up in this study was approximately 2 years; however, an ACL injury could have occurred anywhere between 4 years before follow-up to just one month before follow-up, which creates a gap of knowledge regarding when changes may be initiated and if they are activity dependent. Among the uninjured cadets, there was a slight decrease in biochemical markers over time, which warrants a closer look as to whether physical-activity levels and age were influencing these changes. Clinically, we need to understand if there is an optimal time to potentially thwart OA onset and how best to mitigate its progression. It would be interesting if the authors could continue to follow these participants to see who develops OA in the future. In the meantime, this study provides further evidence that as clinicians, there is a potential for us to make an immediate difference on the long-term health of individuals who suffer a knee injury.
Questions for Discussion: Do you think that we have enough information to potentially develop OA prevention strategies? What do you think may be the next logical steps in trying to prevent OA progression?
Written by: Nicole Cattano
Reviewed by: Laura McDonald