Graft selection in reconstruction of anterior cruciate ligament–a biomechanical study

The anterior cruciate ligament (ACL) lesion is one the most frequent pathologies of the knee joint, especially in the active young population. Although reconstruction of the ACL has been performed for almost 100 years, it continues to evolve, with many technical issues still under debate. These refer to reconstruction technique, but also to graft selection, that should have biomechanical properties similar to the native ligament, while allowing a secure fixation and ligamentization. Also, there is still no consensus on the ideal graft. We performed an experimental study using 8fresh cadaveric knee specimens from 4 donors. We analyzed the anatomy of ACL and performed biomechanical tests on grafts harvested (patellar tendon, hamstring, quadriceps), testing the resistance and breaking point on the commonly used grafts in our clinic. We aimed to evaluate the grafts from the point of view of mechanical properties using a tensile failure test. The main outcome measure was the maximum failure load (N). The second outcome was elongation at failure (mm). Our results showed that the hamstrings tendon had the highest elongation and load to failure rate off all the grafts tested. Results are greatly influenced by the age of donor, size of the graft, time between harvest and testing, as well as preservation technique before testing. At this moment, graft selection usually depends upon the surgeon’s preference and experience, on the activity level of the patient, tissue availability, and general and local comorbidities. The resistance of the graft is only one of the components we should take into consideration when deciding which graft to use.