US researchers said this week that a newer surgical technique results in a stronger, more natural ACL repair.
The team at the University of Missouri School of Medicine developed a research model to compare the level of healing achieved by different surgical methods, in order to determine the best option for graft integration.
Reporting on the findings, the University of Missouri said that ACL repair traditionally involves surgeons creating a tunnel in the upper and lower bones of the knee joint. Each end of the graft is then secured to the sides of these tunnels using screws to press the new ligament against the tunnel walls. This method secures the graft to the bones during the healing process, allowing the new ligament to attach and function as an ACL replacement.
“The traditional repair does provide stability and allows the new graft to grow to bone,” said James Cook, senior author of the study. “However, the graft-to-bone attachment with this method is more like a spot weld, rather than a fully integrated repair. Additionally, the press-fit mechanism of the screws can cause cell and tissue damage in the new graft. Both of these issues result in a repair that may be prone to failure.”
To find out if surgical methods could be improved, the researchers used a canine model to compare the traditional method with a suspensory fixation repair.
“With the newer suspensory system, sutures pull the graft into sockets created in the two bones,” Cook explained. “The sutures are secured to a button on the surface of the bones to hold the graft in place. With this method, the graft fills the entire socket like a potted plant, allowing the graft the best opportunity to fully integrate into the bone like a normal ligament. The suspensory method also reduces cell and tissue damage to the graft.”
Results showed that only four of the six dogs treated with the traditional screw fixation method achieved full functional healing, and none of the grafts fully integrated into the bones like a native ligament. Of the dogs treated with the newer suspensory system, all six achieved functional and natural healing.
“Using our research model, we were able to validate that the suspensory fixation method is not only stronger in terms of securing the graft initially, but also results in more natural healing,” Cook said. “This newer method provides the best option for achieving graft-to-bone integration, and may allow patients to return to a more active lifestyle with a new ACL that is less likely to fail.”
The team´s findings have been published in the Journal of Arthroscopic & Related Surgery.