Combine tension, flexion and torsion. Flexion and torsion vary with direction and placement of the tunnels but cannot be eliminated. Synthetic ligaments must be adapted to these types of stresses.
The previous ligaments were ail braided, woven or knitted. Tests were done on knee mechanical simulators reproducing torsion and flexion. They demonstrated that the ruptures were occuring at the crossing of the fiber's by a reciprocal shearing process of one fiber on the other And this shearing process was inducing microparicules. It was concluded that the crossing of fibers had to be eliminated to increase the resistance to torsion and flexion.
