Using a new, noninvasive rodent model of ACL injury very similar to human’s, researchers have found the first known direct link between altered gait and knee osteoarthritis.
Almost half of patients who undergo surgery to repair a torn anterior cruciate ligament will develop knee osteoarthritis.
Rehabilitation specialists and researchers have long hypothesized that ACL injury results in gait changes that contribute to the onset of osteoarthritis, says Lindsey Lepley, assistant professor of kinesiology at the University of Michigan.
“This study helps to firmly justify the need for gait-retraining after ACL injury,” Lepley says. “If it is not already being undertaken, we suggest patients with ACL injuries talk with their rehab specialists about incorporating a gait retraining program into recovery.
“Many studies and clinical interventions stand on the hypothesis that altered gait drives osteoarthritis development, but there really is a lack of data to substantiate this claim.
“Our data provides a clear link that gait matters, and bad gait is associated with worse knee health. From a clinical standpoint, this means that changing the way people walk after injury may in fact be a good way to help keep joints healthier.”
The ACL is one of the ligaments that connects the femur (thigh bone) to the tibia (shin bone). It runs diagonally through the knee and helps stabilize it by preventing the tibia from sliding out in front of the femur. It also provides rotational stability to the knee.
Gait deficits the team observed in their animal model of ACL injury include limping and stiffness, and are “very similar to what we see in humans, where they have reduced knee flexion angles that get worse over time as joint health deteriorates.”
The researchers found that knee flexion angles and bone architecture were severely impacted after ACL injury and that the biomechanical adaptations in gait resulted in considerable losses of bone volume.
“A significant challenge for the rehabilitation community is understanding which factors to target with treatments and when,” Lepley says. “Developing models of injury that closely replicate the human injury condition is key to testing treatments aimed at slowing or preventing osteoarthritis.”
The paper appears in the Journal of Orthopedic Research.
Source: University of Michigan