Lin Yimiao, Cui Fengting, Jia Zhaofeng, Hu Xinjia, Lin Shiyuan
Department of Trauma Orthopedic, Shenzhen People's Hospital, The Second Clinical, Medical College of Jinan University and The First Affiliated Hospital of Southern University of Science and Technology, No. 1017 Dongmen North Road, Luohu District, Shenzhen, Guangdong, 518035, China.
BMC Musculoskelet Disord. 2025 May 15;26(1):479. doi: 10.1186/s12891-025-08722-9.
This study aims to assess the biomechanical performance of the 7.3 mm fully threaded off-axis screw (7.3-FTOS) configuration in stabilizing vertical femoral neck fractures (FNSs), comparing its effectiveness with other fixation methods.
A vertical FNF model with an 80° Pauwels angle was simulated and stabilized using four internal fixation constructs: Three inverted cannulated compression screws (ICCS), 7.3 mm partially threaded off-axis screw (7.3-PTOS), 4.5 mm fully threaded off-axis screw (4.5-FTOS), and 7.3-FTOS. The fracture fixation models were developed, refined, and optimized using Geomagic for 3D reconstruction and surface smoothing, and SolidWorks for parametric modeling. Comparative finite element analysis was then conducted using Ansys to assess the biomechanical behavior of each fixation method.
The maximum femoral displacements for ICCS, 7.3-PTOS, 4.5-FTOS and 7.3-FTOS were 10.40 mm, 8.08 mm, 7.71 mm, and 7.15 mm, respectively. The peak internal fixation displacements were 9.76 mm, 7.55 mm, 7.25 mm, and 6.78 mm, respectively. The maximum gap displacement measured 2.73 mm, 1.19 mm, 0.94 mm, and 0.55 mm, respectively. The maximum displacement along the Z-axis, representing the shear force direction, was recorded as 2.93 mm, 2.69 mm, 2.66 mm, and 2.63 mm, respectively. The peak von Mises stress (VMS) values in the distal femur were 218.04 MPa, 121.99 MPa, 123.42 MPa, and 113.86 MPa, respectively. The peak VMS values of the internal fixation constructs were 10.40 mm, 8.08 mm, 7.71 mm, and 7.15 mm, respectively.
Finite element analysis results revealed that 7.3-FTOS configuration exhibited superior resistance to shear and rotational forces in vertical FNFs compared to ICCS, 7.3-PTOS, and 4.5-FTOS, demonstrating enhanced mechanical performance. These findings establish a foundation for advancing experimental investigations and potential future clinical translation.
本研究旨在评估7.3毫米全螺纹偏轴螺钉（7.3-FTOS）构型在稳定垂直型股骨颈骨折（FNS）方面的生物力学性能，并将其有效性与其他固定方法进行比较。
模拟了一个 Pauwels 角为80°的垂直型股骨颈骨折模型，并使用四种内固定结构进行稳定固定：三根倒置空心加压螺钉（ICCS）、7.3毫米部分螺纹偏轴螺钉（7.3-PTOS）、4.5毫米全螺纹偏轴螺钉（4.5-FTOS）和7.3-FTOS。使用Geomagic进行三维重建和表面平滑处理，以及使用SolidWorks进行参数化建模，开发、完善和优化骨折固定模型。然后使用Ansys进行比较有限元分析，以评估每种固定方法的生物力学行为。
ICCS、7.3-PTOS、4.5-FTOS和7.
