Biomechanical characteristics of an implant used to secure semitendinosus-gracilis tendon grafts in a canine model of extra-articular anterior cruciate ligament reconstruction

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OBJECTIVE: To compare initial femoral fixation properties of a new implant, Graftgrab (GG), with 2 established methods of extra-articular femoral graft fixation, spiked washers (SW) and bone staples (ST). STUDY DESIGN: Experimental in vitro cohort study. METHODS: Canine semitendinosus-gracilis tendon grafts were passed through bone tunnels and fixed to the lateral surface of femoral condyles with spiked washers, bone staples, or new implant prototypes. The fixations were tested to failure with a single-cycle load at a rate of 50 mm/min. Failure and yield strength, stiffness, energy, and elongation were determined from load-displacement curves and failure modes were recorded. RESULTS: The graft failed midsubstance in 4 SW, 4 ST, and 1 GG fixations. In 3 SW, 3 ST, and 1 GG specimens, the graft slipped from the fixation. The graft ruptured at the clip (3) and the intra-articular (2) surface of the bone tunnel in the remaining GG specimens. There were no significant differences between fixation groups in femoral tunnel length, femoral width, or the mechanical properties evaluated. CONCLUSIONS: The initial in vitro mechanical properties of the new fixation implant are comparable with those of spiked washers and bone staples. CLINICAL RELEVANCE: The initial mechanical performance of the new implant tested in this study was similar to those of comparable, established implants. The new implant is novel and may be useful for human anterior and veterinary cranial cruciate ligament graft reconstruction fixation.

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Veterinary surgery : VS

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