Evaluation of a new femoral fixation device in a simulated anterior cruciate ligament reconstruction.

Abstract

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. 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. 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. 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. 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.