Cross-elements to enhance fixation in osteoporotic bone with application to proximal humeral locking plates: a biomechanical study
| Autor: | Saaransh Jain, Hans E. Lapica, William S. Pietrzak, Eduardo Gonzalez-Hernandez |
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| Rok vydání: | 2020 |
| Předmět: |
Bone Screws
Polyurethanes Locking plate Fracture Fixation Internal 03 medical and health sciences Fixation (surgical) 0302 clinical medicine Materials Testing Axial displacement medicine Humans Orthopedics and Sports Medicine Orthodontics 030222 orthopedics business.industry Stiffness 030229 sport sciences General Medicine Biomechanical Phenomena Peak load Shoulder Fractures Osteoporotic bone Osteoporosis Surgery medicine.symptom business Bone Plates |
| Zdroj: | Journal of Shoulder and Elbow Surgery. 29:1606-1614 |
| ISSN: | 1058-2746 |
| DOI: | 10.1016/j.jse.2019.12.017 |
| Popis: | Background Proximal humeral fractures occur predominantly in elderly, osteoporotic individuals, especially women, with surgery performed in one-fifth. Proximal humeral locking plates are the gold standard operative treatment; however, complications are frequent, partially because of poor screw purchase in osteoporotic bone. A new method uses threaded posts through which threaded cross-elements orthogonally pass to create a 3-dimensional scaffold for bone engagement. We examined the pullout characteristics of the posts with (1 or 2) or without the cross-elements and tested 2 types of 3.5-mm cortical locking screws for comparison. Methods Low-density closed-cell polyurethane foam served as a model osteoporotic bone substrate. Following implantation in the substrate, the devices were axially loaded by a mechanical test system. Quantities of interest included failure mode, peak load, displacement to peak load, initial stiffness, and work expended. Results The post groups outperformed the 3.5-mm screw groups, as expected. Relative to posts with no cross-elements, 1 and 2 cross-elements increased the peak load by 29% and 87% and increased the work to peak load by 126% and 343%, respectively. After reaching peak load, 1 and 2 cross-elements increased the work-resistance to further displacement by 158% and 330%, respectively. Conclusion Cross-elements significantly increased the ability of the threaded posts to resist axial displacement from a model osteoporotic bone substrate. This suggests that posts, used in conjunction with cross-elements, have the potential to enhance the stability of proximal humeral locking plates in osteoporotic bone. |
| Databáze: | OpenAIRE |
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