3d microstructural changes in human anterior cruciate ligament under increasing mechanical strain

When the knee joint Anterior Cruciate Ligament (ACL) is injured, the common approach requires its surgical reconstruction by using several types of graft. Unfortunately, inappropriate graft properties are still main issues in reaching a long-term success [1]. Dense fibrous tissues, such as ACL, typically present nonlinear stress-strain characteristics related to fibres uncrimping, reorienting and tensioning, which inherently define its functional properties. ACL fibres behaviour was already investigated under load, but considering only external surface by using polarization imaging technique [2]. On the other hand, a 3d investigation of fibrous structure was performed by micro-CT, but considering only artificial scaffolds and no loading [3]. Aim of this study was to design and test a dedicated setup able to acquire the volumetric fibrous microstructure of ACL samples, under increasing mechanical strain