Department of Orthopedic, Baoding No. 1 Central Hospital, Baoding, Hebei Province, 071000, China.
Department of Spinal Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei Province, 050000, China.
BMC Musculoskelet Disord. 2024 Oct 4;25(1):789. doi: 10.1186/s12891-024-07907-y.
Despite the explicit biomechanical advantages associated with FNS, it is currently inconclusive, based on the existing literature, whether Femoral Neck System (FNS) outperforms Cannulated cancellous screws (CSS) in all aspects. Due to variances in bone morphology and bone density between the elderly and young cohorts, additional research is warranted to ascertain whether the benefits of FNS remain applicable to elderly osteoporosis patients. This study aimed to investigate the biomechanical properties of FNS in osteoporotic femoral neck fractures and propose optimization strategies including additional anti-rotation screw.
The Pauwels type III femoral neck fracture models were reconstructed using finite element numerical techniques. The CSS, FNS, and modified FNS (M-FNS) models were created based on features and parameterization. The various internal fixations were individually assembled with the assigned normal and osteoporotic models. In the static analysis mode, uniform stress loads were imposed on all models. The deformation and stress variations of the femur and internal fixation models were recorded. Simultaneously, descriptions of shear stress and strain energy were also incorporated into the figures.
Following bone mass reduction, deformations in CSS, FNS, and M-FNS increased by 47%, 52%, and 40%, respectively. The equivalent stress increments for CSS, FNS, and M-FNS were 3%, 43%, 17%, respectively. Meanwhile, variations in strain energy and shear stress were observed. The strain energy increments for CSS, FNS, and M-FNS were 4%, 76%, and 5%, respectively. The shear stress increments for CSS, FNS, and M-FNS were 4%, 65% and 44%, respectively. Within the osteoporotic model, M-FNS demonstrated the lowest total displacement, shear stress, and strain energy.
Modified FNS showed better stability in the osteoporotic model (OM). Using FNS alone may not exhibit immediate shear resistance advantages in OM. Concurrently, the addition of one anti-rotation screw can be regarded as a potential optimization choice, ensuring a harmonious alignment with the structural characteristics of FNS.
尽管与 FNS 相关的明确生物力学优势，但基于现有文献，目前还不能确定 FNS 在所有方面都优于空心加压螺钉（CSS）。由于老年和年轻人群的骨形态和骨密度存在差异，需要进一步研究以确定 FNS 的益处是否仍然适用于老年骨质疏松症患者。本研究旨在研究骨质疏松性股骨颈骨折中 FNS 的生物力学特性，并提出优化策略，包括增加抗旋转螺钉。
使用有限元数值技术重建 Pauwels Ⅲ型股骨颈骨折模型。根据特征和参数化创建 CSS、FNS 和改良 FNS（M-FNS）模型。将各种内固定器单独与指定的正常和骨质疏松模型组装在一起。在静态分析模式下，在所有模型上施加均匀的应力载荷。记录股骨和内固定模型的变形和应力变化。同时，还将剪切应力和应变能的描述纳入图中。
在骨量减少后，CSS、FNS 和 M-FNS 的变形分别增加了 47%、52%和 40%。CSS、FNS 和 M-FNS 的等效应力增量分别为 3%、43%和 17%。同时，观察到应变能和剪切应力的变化。CSS、FNS 和 M-FNS 的应变能增量分别为 4%、76%和 5%。CSS、FNS 和 M-FNS 的剪切应力增量分别为 4%、65%和 44%。在骨质疏松模型中，M-FNS 的总位移、剪切应力和应变能最小。
改良 FNS 在骨质疏松模型（OM）中表现出更好的稳定性。单独使用 FNS 可能不会在 OM 中立即表现出抗剪优势。同时，添加一个抗旋转螺钉可以被视为一种潜在的优化选择，确保与 FNS 的结构特征保持和谐一致。
