Wuxi 9th People's Hospital Affiliated to Soochow University, Wuxi 214023, China.
School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China.
Injury. 2024 Dec;55(12):111979. doi: 10.1016/j.injury.2024.111979. Epub 2024 Oct 23.
This study aims to investigate the biomechanical characteristics of non-anatomical reduction and different screw positions on the stability of Pauwels type III femoral neck fractures.
Three-dimensional finite element models of femoral neck fractures were constructed using CT images. Four types of internal fixation methods were simulated, including biplane double-supported screw fixation (BDSF), three inverted triangular parallel cannulated screws (3CS), new parallel cannulated screws with posterior screws moving down (New 3CS), and two parallel cannulated screws (2CS). von Mises stress and total displacement were compared between the fracture models after the femoral head was subjected to an axial load of 2100 N. Stress and displacement data for the implants and the femur were recorded for each fixation method and compared.
The results demonstrated that positive reduction of a Pauwels type III femoral neck fracture provided greater stability than neutral or negative reduction. Specifically, the BDSF group showed the lowest maximum von Mises stress in the femur (17.66 MPa) in positive reduction, compared to 3CS (21.08 MPa), New 3CS (22.14 MPa), and 2CS (36.57 MPa). The total displacement of positive reduction in the BDSF group was 0.3143 mm, which was lower than in the 3CS (0.3498 mm), New 3CS (0.3343 mm), and 2CS (0.4533 mm) groups. The stress distribution in the positive support reduction group was lower than that of the other groups, indicating better load distribution. Among the three-screw fixation methods, the New 3CS system exhibited the highest stress in the screws (with a peak of 28.62 MPa), while the 2CS group displayed the highest stresses overall, both in the femur and the screws.
For Pauwels type III femoral neck fractures, a positive support reduction with BDSF fixation exhibited superior biomechanical performance than negative reduction. Based on the finite element analysis conducted in this study, the positive support reduction with BDSF fixation can enhance fixation stability, suggesting that non-anatomical reduction is recommended.
本研究旨在探讨非解剖复位和不同螺钉位置对 Pauwels Ⅲ型股骨颈骨折稳定性的生物力学特性。
使用 CT 图像构建股骨颈骨折的三维有限元模型。模拟了四种内固定方法，包括双平面双支撑螺钉固定（BDSF）、三倒三角平行空心钉（3CS）、新型后移螺钉的平行空心钉（New 3CS）和两平行空心钉（2CS）。在对股骨头施加 2100N 的轴向载荷后，比较骨折模型的股骨头后，比较骨折模型的 von Mises 应力和总位移。记录每种固定方法的植入物和股骨的应力和位移数据，并进行比较。
结果表明，Pauwels Ⅲ型股骨颈骨折的正位复位比中性或负位复位提供更大的稳定性。具体来说，在正位复位中，BDSF 组的股骨最大 von Mises 应力最低（17.66MPa），而 3CS 组（21.08MPa）、New 3CS 组（22.14MPa）和 2CS 组（36.57MPa）。BDSF 组正位复位的总位移为 0.3143mm，低于 3CS 组（0.3498mm）、New 3CS 组（0.3343mm）和 2CS 组（0.4533mm）。正位支撑复位组的应力分布低于其他组，表明负荷分布更好。在三螺钉固定方法中，新型 3CS 系统的螺钉内应力最高（峰值为 28.62MPa），而 2CS 组的股骨和螺钉内总体应力最高。
对于 Pauwels Ⅲ型股骨颈骨折，BDSF 固定的正支撑复位比负支撑复位具有更好的生物力学性能。基于本研究的有限元分析，BDSF 固定的正支撑复位可以增强固定稳定性，表明不解剖复位是推荐的。
