Cross-elements to enhance fixation in osteoporotic bone with application to proximal humeral locking plates: a biomechanical study.
J Shoulder Elbow Surg
; 29(8): 1606-1614, 2020 Aug.
Article
en En
| MEDLINE
| ID: mdl-32147335
ABSTRACT
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.Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Placas Óseas
/
Tornillos Óseos
/
Fijación Interna de Fracturas
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
J Shoulder Elbow Surg
Asunto de la revista:
ORTOPEDIA
Año:
2020
Tipo del documento:
Article
País de afiliación:
Estados Unidos