Young adults who undergo anterior cruciate ligament (ACL) surgery, typically athletes, may be at a higher risk of developing early-stage osteoarthritis (OA) in their 20s and 30s. New research involving X-ray evidence aims to understand the link, and limit the number of affected individuals.
Thomas Buchanan, professor of mechanical engineering at the University of Delaware (UD), partnered with Lynn Snyder-Mackler, professor of physical therapy at UD, to investigate the connection between ACL surgery and OA so therapeutic interventions can be developed to prevent it.
“We want to determine why some people get OA after ACL repair, and determine if those people can be readily identified very early,” Buchanan told HCB News. “If so, we ultimately would like to create a physical therapy protocol aimed at preventing the development of OA in that population.”
They recently received a $357,234 grant from the National Institutes of Health to evaluate the biochemical and biomechanical bases for the development of OA after ACL surgery. The two have been working together for over 15 years, and have already uncovered that some patients displayed unusual gait mechanics six months after ACL surgery.
More specifically, they found that immediately after the injury the knee starts unloading, in which the joint contact force is less in the involved knee than the uninvolved knee when walking. After six months, the knee is still unloading.
For the new study, they are going to evaluate patients three months, six months and two years after ACL surgery. Initially they are going to use gait analysis and electromyography to assess the biomechanical basis of the unloading. Then they’ll use quantitative MR imaging to observe any biochemical changes in the cartilage. Lastly, they will use a finite element model to examine the effect that differences in knee loading has on knee cartilage stress distribution.
The team believes that research will help them understand the mechanisms behind knee unloading after ACL surgery. Having that understanding will help them make recommendations for clinical treatment paths to prevent OA in that population.
“At present, we do not understand what causes osteoarthritis (OA) in people after ACL surgery. Some get OA, others do not,” said Buchanan. “Until we can identify who will get OA and why, she won't be able to formulate a treatment path.”
