An experimental study of the microstructures and mechanical properties of swine cruciate ligaments

Abstract

Tensile tests were performed on bone-ligament-bone (BLB) units, sections of ligament, and individual collagen fascicles all from the knees of swine hind legs. A universal testing machine was used for the tensile tests of the BLB units. A specially designed test apparatus was used for the tensile tests of ligament sections and fascicles. The strain values were calculated from the elongation values recorded by a video camera. The results showed that the BLB's stiffness was greatest, followed by the fascicles and the ligament sections. The results are contrary to the popular notion that because the ligament is composed of collagen fascicles in a matrix whose stiffness is almost negligible, the ligament should not be stiffer than the fascicles that compose it. The stiffness might have been caused by mechano-chemical interactions between fascicles and matrix, or contributions from the membranous septum that combines fascicles.