The effect of cyclic loading on the mechanical properties of artificial ligaments

In this study, artificial anterior cruciate ligaments (ACLs) were manufactured using braiding and knitting processes. These artificial ligaments were designed to match the mechanical requirements of a native human ACL, including the fatigue performance. The effect of cyclic loading on the mechanical performance of the artificial ligaments was studied at different deformation rates (slow: 2% per second, medium: 50% per second and fast: 100% per second). The primary results showed that the deformation rate had no significant effect on the ultimate tensile strength, strain or stiffness. Single tensile loading to failure performed for each prosthesis before and after cyclic loading allowed the determination of its effect on the mechanical performance of the artificial ligaments. The increase in the number of cycles decreased the maximum strain and the ultimate tensile strength but had no significant effect on the stiffness. At 60,000th cycle, the braided prosthesis presented a better performance with a lower residual deformation compared with the knitted prosthesis.