In the constantly evolving field of orthopaedic surgery, Anterior Cruciate Ligament (ACL) reconstruction techniques are continuously being refined to improve patient outcomes. A key area of research is the biomechanical strength of the graft and its fixation method. This study delves into this by comparing three modern, quadrupled tendon graft constructs with adjustable suspensory fixation against a more traditional four-strand graft fixed with screws. The findings provide valuable insights into which methods offer superior stability and durability.
The Importance of Graft Stability and Fixation
A successful ACL reconstruction relies on a graft that can withstand the physical forces of daily life and sport without stretching or failing. The fixation method used to secure the graft inside the bone tunnels is the weakest link in this chain. If the fixation is not strong enough, the graft can elongate over time, leading to a loose and unstable knee. This can result in a poorer functional outcome for the patient and an increased risk of re-injury. Surgeons are therefore seeking new techniques that can provide robust fixation and a more durable graft construct.
An Advanced Biomechanical Comparison
This study utilised a rigorous biomechanical testing protocol to evaluate the different constructs. Using matched bovine tendon grafts and porcine tibia models to simulate human anatomy, the researchers subjected the grafts to cyclic loading—mimicking the repetitive motions of walking and running—and a pull-to-failure test to determine their ultimate strength.
The results demonstrated a clear biomechanical advantage for the three novel quadrupled tendon constructs. They showed significantly lower elongation, meaning they stretched less under load, and had a higher ultimate failure load compared to the traditional four-strand graft fixed with a tibial screw. This is a critical finding, as excessive elongation is a primary cause of graft failure and recurrent knee instability. The study also highlighted that the total elongation of the screw-fixed group exceeded the threshold of what is considered clinically acceptable, suggesting a potential risk of long-term laxity.
The Future of ACL Reconstruction
The findings from this research provide strong evidence that quadrupled tendon grafts combined with adjustable loop suspensory fixation offer a superior solution for ACL reconstruction. By providing greater initial stability and durability, these techniques may enhance the healing process, reduce the risk of graft failure, and ultimately lead to better long-term functional outcomes for patients. This work helps guide surgeons towards more reliable and durable fixation methods, representing a significant step forward in patient care.
Professor Wilson’s Comments
“In the early days, I spent many hours in the cadaver lab refining the GraftLink technique, experimenting with different ways to prepare and tension the graft. The technique attracted so much interest that I was soon invited to perform live surgical demonstrations all over the world, helping to pioneer and popularize this minimally invasive All-Inside ACL reconstruction approach.
One of the key collaborations that followed was with Chris Vertullo, who, like myself, was a Peter Myers fellow. Chris did much of the hard work on the biomechanical study we carried out with the Arthrex team, where we tested multiple quadrupled graft configurations. The configuration I introduced proved to be the strongest in terms of mechanical performance and load to failure — confirming that the GraftLink technique had truly become the gold standard in graft preparation.
Chris, who lives on the Gold Coast in Queensland, has surfed every day of his life — quite literally starting his mornings in the ocean before heading to work. My own mornings are a little different: they begin with a double espresso and a brisk walk to the station before heading into Harley Street. Two very different starts to the day, but both approaches seem to work!
The success of this project laid the foundations for the InternalBrace concept, which went on to revolutionize the way we reinforce ligament reconstructions — a development I’m incredibly proud to have been part of.”
For a detailed review of the complete findings, methodology, and analysis, the full research paper is available for your perusal.
Sources used in report overview:
- https://pubmed.ncbi.nlm.nih.gov/30789779/
- https://www.jospt.org/doi/10.2519/jospt.2012.3768
- https://www.omgtb.com/acl-graft/
