Validation of a physiological relevant biomechanical test setup for the investigation of complex pelvic ring fractures

Abstract-Text (inkl. Referenzen und Bildunterschriften)

Objective

Fractures of the human pelvis can lead to disruption of the ring-shaped structure, resulting in mechanical destabilization, for which a variety of osteosynthetic treatment methods are available. The aim of this project is to design a test setup to determine the stability of different fixation methods for complex pelvic ring fractures under loading conditions that simulate human gait.

Methods

In the test setup, the load of the upper body and muscle forces are applied to a pelvis to be tested, alternately loading one side or the other depending on the gait phase. Since not all external forces acting on the pelvis can be recorded simultaneously during the cyclic test, the pelvis is only loaded on one side for validation. The measurement data recorded in this way are compared with the results of an Anybody-simulation of a 66 kg subject at the time of heel strike during walking (Soliman et al., 2023).

Results

The functionality of the test setup is shown in Fig. 1. The forces on the lumbosacral and hip joints are within a range of 20% of the forces determined in the simulation of Soliman et al. The forces on the muscle pulls are within a range of 30%, compared to the summarized muscle forces of the Anybody-simulation.

Conclusion

Up to now, biomechanical experiments on the pelvis have mainly been performed using single- or double-leg stance models. Because these do not fully account for the complex loading situation during gait, the new test setup was developed. Although simplifications were made, especially for the muscle forces, the load distribution agrees well with a multi-body simulation. The new test setup can be used to evaluate the fatigue strength of osteosynthesis used for complex pelvic ring fractures.

Literature

Soliman, Ahmed, et al. "Developing a Biomechanical Testing Setup of the Pelvis—Part I: Computational Design of Experiments." Journal of Biomechanical Engineering 145.10 (2023)

Fig. 1

Rendering of the CAD-model of the test setup