Biomechanical testing
fracture
BENDING
Biomechanical testing was performed on a servo hydraulic material testing system (MTS 858 Bionix, MTS Systems Corp., Eden Prairie, USA) equipped with a 4 kN load cell. Specimens were mounted to the machine in simulated upright standing position by fixing the L5 embedding to the machine transducer via an interconnected hinge joint, allowing for bending moment compensation in flexion–extension. One-leg stance was simulated by transferring the forces generated by the transducer, through the tested hemi-pelvic site to the ipsilateral acetabulum, which was seated on a hip stem with attached hemiarthroplasty component. The latter was firmly constrained to the machine base (Fig. Test setup with specimen mounted for biomechanical testingThe loading protocol commenced with an initial quasi-static ramp from 20 N preload to 100 at a rate of 8 N/s, followed by cyclic loading at 3 Hz under a physiological loading profile [After failure, whereas the dislocated fragments of tested anatomical side were anatomically re-aligned and re-fixed at the sacrum by means of 3 SI-Screws, the rami were re-fixed by plating. Subsequently, the procedure of fracture creation, stabilization, and testing was repeated on the contralateral side.