Evaluation of a New Femoral Fixation Device in a Simulated Anterior Cruciate Ligament Reconstruction

Purpose: The purpose of this in vitro biomechanical study was to determine the cyclic elongation and failure properties of a new anterior cruciate ligament (ACL) reconstruction device and compare the results with several devices that are currently available. Methods: We performed 10 ACL reconstructions in 4 groups using fresh porcine femurs and doubled lateral extensor of the toes tendons. Manufacturer guidelines were followed for fixation by use of either of 2 cortical suspension devices (XO Button [ConMed Linvatec, Largo, FL] and EndoButton CL [Smith & Nephew, Andover, MA]), a bio-interference screw (BioScrew; ConMed Linvatec), or a corticocancellous fixation device (Pinn-ACL; ConMed Linvatec). Reconstructions were subjected to cyclic loading to 150 N for 2,000 cycles, followed by static failure tests. Results: The two cortical suspension devices performed similarly to one another: the XO Button device had a significantly lower elongation amplitude than the EndoButton (P<.05). There were no significant differences in longer-term creep performance or static strength or stiffness. Compared with an interference screw, the XO Button had significantly less creep and higher failure load (P<.05). The corticocancellous device had the lowest creep and cyclic elongation amplitude and the highest strength and stiffness of the devices tested. Conclusions: In this in vitro evaluation, reconstructions with the XO Button and EndoButton exhibited very similar biomechanical performance, and our hypothesis was not supported: the XO Button did not limit creep more than the EndoButton. Clinical Relevance: The results of this preclinical in vitro testing suggest that the new device is expected to provide clinical results similar to those of the EndoButton, a well-established device for ACL reconstruction.