Biomechanical evaluation of novel intra- and extramedullary assembly fixation for proximal humerus fractures in the elderly

• Published in: Frontiers in bioengineering and biotechnology 2023-10, Vol.11, p.1182422-1182422
• Main Authors: Zhu, Zhengguo, Chang, Zuhao, Zhang, Wei, Qi, Hongzhe, Guo, Hao, Li, JiaQi, Qi, Lin, Nie, Shaobo, Tang, Peifu, Liang, Yonghui, Wei, Xing, Chen, Hua
• Format: Article
• Language: English
• Subjects: Bioengineering and Biotechnology; biomechanical analysis; hybrid fixation; intramedullary nail; locking plate fixation; osteopenia; proximal humeral fractures
• ISSN: 2296-4185; 2296-4185
• DOI: 10.3389/fbioe.2023.1182422

Purpose: A novel intra- and extramedullary assembly fixation method was introduced, which achieved good clinical results in complex proximal humeral fractures; however, evidence of its comparability with traditional fixation is lacking. This biomechanical study aimed to compare it with traditional fixation devices in osteoporotic proximal humeral fractures. Methods: Three-part proximal humeral fractures with osteopenia were created on 12 pairs of fresh frozen humerus specimens and allocated to three groups: 1) lateral locking plate, 2) intramedullary nail, and 3) intra- and extramedullary assembly fixation. The specimens were loaded to simulate the force at 25° abduction. Thereafter, an axial stiffness test and a compound cyclic load to failure test were applied. Structural stiffness, number of cycles loaded to failure, and relative displacement values at predetermined measurement points were recorded using a testing machine and a synchronized 3D video tracking system. Results: In terms of initial stiffness and the number of cycles loaded to failure, the intra- and extramedullary assembly fixation group showed notable improvements compared to the other groups ( p