The success of anterior cruciate ligament (ACL) surgery is connected to the way you move after the procedure, according to new research.
Rupture of the ACL, one of four ligaments in your knee, is a common injury in football, netball, tennis, skiing and other sports. Although the injury can be successfully treated, one in three people who undergo ACL reconstruction surgery will have osteoarthritis in their injured knee within 10 years. Within two decades, nearly 50% will.
In a study published in the journal Medicine and Science in Sports and Exercise, researchers from the University of North Carolina (UNC) and Brigham Young University (BYU) investigated why this is the case.
The research involved 130 subjects who had ACL reconstruction surgery between six months and 13 years previously. Participants were fitted with retroreflective markers on their legs and then a 10-camera 3D motion capture system was used to track the positions of the markers during normal walking.
The data revealed that people who report lingering symptoms post-surgery tend to underload or overload their injured leg by 4-5% compared with those who no longer report symptoms.
“At first look, these changes are relatively small,” said lead author Brian Pietrosimone of UNC. “Yet when you think about a 5% difference every step you take every day, over the course of a month, year, or lifetime, you can extrapolate why a seemingly small change could lead to a progressive and chronic disease like post-traumatic osteoarthritis.”
The findings suggest that people who have had ACL reconstruction surgery need to restore movement mechanics in a way that improves their chances of avoiding osteoarthritis. As the study authors explain, this may include closer adherence to a physical therapy programme or increased strength training.
“These data indicate overloading and underloading are likely deleterious to cartilage,” said co-author Matt Seeley, associate professor of exercise sciences at BYU. “This study sets the table for a longitudinal study to determine the precise causes of altered leg biomechanics post-surgery.”