Biomechanical evaluation of four femoral fixation configurations in a simulated anterior cruciate ligament replacement using a new generation of Ligament Advanced Reinforcement System (LARS™ AC)

Abstract

Background Recent improvements in manufacturing of biomaterials have made available a new generation of artificial ligaments with better biocompatibility and design that have led to a new interest in using them for ACL reconstructions. Purpose To evaluate the biomechanical characteristics of four femoral fixations using a Ligament Advanced Reinforcement System (LARS™ AC; LARS, Arc sur Tille, France) for anterior cruciate ligament replacement. Method Six femoral ACL fixations in four configurations using fresh calf femurs with an interference titanium screw inserted inside to outside, an interference titanium screw inserted outside to inside, an interference titanium screw inserted inside to outside with a staple and a new transversal cortical suspension device developed by LARS™ were compared in a static loading and failure test. Output values were ultimate strength, graft slippage, mode of failure, energy to failure and stiffness. Results The transversal fixation performed with a significantly higher failure load than others (1804 N) (p < 0.001), whereas there were no significant differences between the three fixations with interference screws. There were no significant differences of stiffness between all fixations, and the transversal device had a significantly higher graft slippage (13.1 mm) than others (all p < 0.01). Conclusions In this in vitro evaluation, the transversal fixation exhibited better biomechanical performance under static solicitations than others. The transversal device is expected to provide better clinical results than the well-established screw system fixations for femoral ACL fixation.