Department of Hip Trauma, Tianjin Hospital, Tianjin, China.
Tianjin University of Traditional Chinese Medicine, Tianjin, China.
Orthop Surg. 2024 Jul;16(7):1695-1709. doi: 10.1111/os.14069. Epub 2024 May 15.
The current investigation sought to utilize finite element analysis to replicate the biomechanical effects of different fixation methods, with the objective of establishing a theoretical framework for the optimal choice of modalities in managing Pauwels type III femoral neck fractures.
The Pauwels type III fracture configuration, characterized by angles of 70°, was simulated in conjunction with six distinct internal fixation methods, including cannulated compression screw (CCS), dynamic hip screw (DHS), DHS with de-rotational screw (DS), CCS with medial buttress plate (MBP), proximal femoral nail anti-rotation (PFNA), and femoral neck system (FNS). These models were developed and refined using Geomagic and SolidWorks software. Subsequently, finite element analysis was conducted utilizing Ansys software, incorporating axial loading, torsional loading, yield loading and cyclic loading.
Under axial loading conditions, the peak stress values for internal fixation and the femur were found to be highest for CCS (454.4; 215.4 MPa) and CCS + MBP (797.2; 284.2 MPa), respectively. The corresponding maximum and minimum displacements for internal fixation were recorded as 6.65 mm for CCS and 6.44 mm for CCS + MBP. When subjected to torsional loading, the peak stress values for internal fixation were highest for CCS + MBP (153.6 MPa) and DHS + DS (72.8 MPa), while for the femur, the maximum and minimum peak stress values were observed for CCS + MBP (119.3 MPa) and FNS (17.6 MPa), respectively. Furthermore, the maximum and minimum displacements for internal fixation were measured as 0.249 mm for CCS + MBP and 0.205 mm for PFNA. Additionally, all six internal fixation models showed excellent performance in terms of yield load and fatigue life.
CCS + MBP had the best initial mechanical stability in treatment for Pauwels type III fracture. However, the MBP was found to be more susceptible to shear stress, potentially increasing the risk of plate breakage. Furthermore, the DHS + DS exhibited superior biomechanical stability compared to CCS, DHS, and PFNA, thereby offering a more conducive environment for fracture healing. Additionally, it appeared that FNS represented a promising treatment strategy, warranting further validation in future studies.
本研究旨在利用有限元分析来复制不同固定方法的生物力学效应，以期为 Pauwels Ⅲ型股骨颈骨折的最佳治疗方式选择提供理论依据。
模拟 Pauwels Ⅲ型骨折形态（角度为 70°），联合 6 种不同的内固定方法，包括空心加压螺钉（CCS）、动力髋螺钉（DHS）、带旋转移位螺钉的 DHS（DS）、CCS 联合内侧支撑钢板（MBP）、股骨近端防旋髓内钉（PFNA）和股骨颈系统（FNS）。采用 Geomagic 和 SolidWorks 软件建立并优化模型，再利用 Ansys 软件进行有限元分析，包括轴向加载、扭转加载、屈服载荷和循环加载。
在轴向加载条件下，CCS（454.4；215.4 MPa）和 CCS+MBP（797.2；284.2 MPa）的内固定和股骨的峰值应力值最高。CCS 的最大和最小内固定位移分别为 6.65mm 和 6.44mm。在扭转加载下，CCS+MBP（153.6 MPa）和 DHS+DS（72.8 MPa）的内固定峰值应力值最高，而 CCS+MBP（119.3 MPa）和 FNS（17.6 MPa）的股骨最大和最小峰值应力值最高。此外，CCS+MBP 的最大和最小内固定位移分别为 0.249mm 和 0.205mm。所有 6 种内固定模型在屈服载荷和疲劳寿命方面均表现出色。
CCS+MBP 在治疗 Pauwels Ⅲ型骨折时初始机械稳定性最好。然而，MBP 更容易受到剪切力的影响，从而增加钢板断裂的风险。此外，与 CCS、DHS 和 PFNA 相比，DHS+DS 表现出更好的生物力学稳定性，为骨折愈合提供了更有利的环境。另外，FNS 似乎是一种很有前途的治疗策略，值得进一步在未来的研究中验证。
