Approach to standardized material characterization of the human lumbopelvic system - Testing and evaluation

The osseo-ligamentous lumbopelvic complex is a crucial component of the human musculoskeletal system and has been increasingly the focus of medical research and treatment planning. Numerical simulations can play a key role in better understanding the load-carrying behavior of this system, but material data in this arena remain rare. In addition, the literature lacks standardized and reproducible methods for determining biomechanical material parameters. To address these shortcomings, we obtained bone and soft tissue samples from three female and two male cadavers (average age: 77.3 years) for testing and evaluation. The elastic modulus of cortical bone averaged at 1750 MPa with a mean ultimate strength of 28.2 MPa. Whereas for trabecular bone the evaluation yields to 32.7 MPa and 1.26 MPa. Furthermore, the soft tissue specimens exhibited a mean elastic modulus of 148 MPa and an ultimate strength of 14.3 MPa for fascial tissue, in contrast to ligamentous tissue with 103 MPa and 10.7 MPa. Knowledge of these material parameters of the human pelvis, which differ from those of long bones, could, in combination with the revealed dependence on harvesting location and density, lead to more precise mechanical simulations. Such simulations might in turn promote the development of better suited implants. Together with a previous publication dealing with sample preparation, this work is intended to contribute to the standardization of mechanical testing of human tissue. Easy-to-conduct bending tests as well as direct tension and compression tests are recommended, and the proposed mechanical boundary conditions are explained and documented. These technical recommendations allow for better comparability and reproducibility in future biomechanical studies. This protocol, developed for the human pelvis, could easily be transferred to other anatomical regions.