The long-term success of anterior cruciate ligament (ACL knee) reconstruction is tied to how you "move" after surgery, finds this team from Brigham Young University in Utah, who set out to understand why many ACL patients end up with knee osteoarthritis. This study, presented in the journal Medicine & Science in Sports & Exercise, shows the importance of avoiding both underload and overload, which are harmful to the cartilage, and therefore of restoring the mechanics of movement, through physiotherapy for example, so as to improve the chances of avoiding osteoarthritis.
One in 3 patients who undergo ACL reconstruction surgery will suffer from knee osteoarthritis within 10 years of their surgery. And one in two patients has a very high risk of suffering from an irrecoverable physical handicap. Seeking to explain this difficulty in recovery, the team explored 2 theories:
- the knee injury itself can cause persistent and chronic inflammation leading to underlying tissue changes;
- patients who sustain this ACL injury end up moving differently during activities like running, jumping, and walking, which worsens cartilage damage over time.
Based on these theories, Brigham Young University researchers with their colleagues at the University of North Carolina observed the gait biomechanics of 130 subjects who underwent ACL reconstruction surgery, between 6 months and 13 months old. years before. The participants, fitted with retroreflective markers on their legs, captured by cameras, were asked to walk as if they were walking normally and quietly on a sidewalk, at a constant speed. In particular, the researchers collected data on the reaction force of the ground on the injured leg during walking. This analysis concludes with a determining factor for the symptoms of pain and osteoarthritis, the underload or the overload of the operated leg:
- people who report persistent symptoms after surgery overload or underload walking their injured leg;
- specifically, the symptomatic group overloads or underloads the injured leg 4 to 5% more than the asymptomatic group.
A difference of 5% load at each step: thus, the effectiveness of the reconstruction of the ACL is obviously not called into question here, it is rather the mode of recovery that holds the attention: "The way you move is linked to the outcome of your surgery,” summarize the authors. "At first glance, these load differences may seem relatively small, however, a difference of 5% at each step, during each month, each year and then over a lifetime can lead to a progressive and chronic disease such as osteoarthritis. Posttraumatic ".
What are the implications for patients? the authors recommend that patients who have undergone this ACL reconstruction surgery take care to "restore the mechanics of movement in such a way as to improve the chances of avoiding osteoarthritis".
Concretely, this involves joining a physiotherapy or strength-building program. Under surveillance, of course.
