Bones provide support to the human body as well as protection of vital organs. During daily activities, such as walking and running, fatigue loading causes formation of microcracks. However, different mechanisms exist that repair this type of damage in healthy individuals. Bone diseases that influence bone turn-over, such as osteoporosis, might influence the formation and repair mechanisms of microcracks, resulting in an increase of microdamage. So far, microdamage characterization was limited to tests on mm-sized bone cores, e.g. network of trabecular bone, making it impossible to separate the structural influence from the actual microcrack growth. In a previous study [1] a set-up for testing individual trabeculae in tension was developed and characterization of trabecular bone at the material level was performed. This set-up was extended to test individual trabeculae in fatigue mode to induce microdamage at a defined load state. Sequentially, individual trabeculae have to be stained with chelating agents to visualize microdamage (see figure 1-B). First results clearly showed the formation of mainly diffuse microdamage with increasing load cycles, in bovine bone. Continuing from this, the first goal of the current thesis is to use the developed test set-up to continue with testing of bovine trabeculae at defined load cycles. Sequentially, the main work will be to investigate differences in the microdamage formation and growth of human cadaveric and osteoporotic trabeculae. The advantage of this approach is to determine possible differences in both, pre-existing microdamage and induced microcrack growth. The work consists of getting familiar with the established set-up and testing protocol, such as sample preparation (see figure 1-A) and fatigue testing. Inclusion of potential improvements of the test procedure is welcomed. Additionally, histology and handling a confocal laser scanning microscope will be performed to label and visualize microdamage (see figure 1-B). The work is interdisciplinary and offers insights into various research areas and the ability to obtain skills in a variety of different techniques.

Incoming