Department of Trauma Orthopaedics, Shanghai East Hospital, Tongji University School of Medicine, 150 Jimo Road, Shanghai, 200120, China.
BMC Musculoskelet Disord. 2024 Jun 6;25(1):446. doi: 10.1186/s12891-024-07550-7.
Femoral neck system (FNS) has exhibited some drawbacks, such as non-fit of the plate with the lateral femoral cortex, postoperative pain, and the potential risk of subtrochanteric fractures. We have developed a low-profile FNS system that addresses some compatibility issues in FNS. In this study, we conducted finite element analysis on the 1-hole FNS (1 H-FNS), 2-holes FNS (2 H-FNS), and low-profile FNS (LP-FNS) and compared their biomechanical performance.
After the mesh convergence analysis, we established three groups of 1 H-FNS, 2 H-FNS, and LP-FNS. The interfragmentary gap, sliding distance, shear stress, and compressive stress and the bone-implant interface compression stress, stiffness, and displacement were determined under the neutral, flexion, or extension conditions of the hip joint, respectively. The stress and displacement of the femur after the implant removal were also investigated.
(1) There were no obvious differences among the three FNS groups in terms of the IFM distance. However, the LP-FNS group showed less rotational angle compared with conventional FNS (neutral: 1 H-FNS, -61.64%; 2 H-FNS, -45.40%). Also, the maximum bone-implant interface compression stress was obviously decreased under the neutral, flexion, or extension conditions of the hip joint (1 H-FNS: -6.47%, -20.59%, or -4.49%; 2 H-FNS: -3.11%, 16.70%, or -7.03%; respectively). (2) After the implant removal, there was no notable difference in the maximum displacement between the three groups, but the maximum von Mises stress displayed a notable difference between LP-FNS and 1 H-FNS groups (-15.27%) except for the difference between LP-FNS and 2 H-FNS groups (-4.57%).
The LP-FNS may not only provide the same biomechanical stabilities as the 1 H-FNS and 2 H-FNS, but also have more advantages in rotational resistance especially under the neutral condition of the hip joint, in the bone-implant interface compression stress, and after the implant removal. In addition, the 1 H-FNS and 2 H-FNS have similar biomechanical stabilities except for the maximum von Mises stress after the implant removal. The femur after the LP-FNS removal not only is subjected to relatively little stress but also minimizes stress concentration areas.
股骨颈系统（FNS）存在一些缺点，例如与外侧股骨皮质不匹配、术后疼痛以及潜在的转子下骨折风险。我们开发了一种低切迹的 FNS 系统，解决了 FNS 中的一些兼容性问题。在这项研究中，我们对 1 孔 FNS（1H-FNS）、2 孔 FNS（2H-FNS）和低切迹 FNS（LP-FNS）进行了有限元分析，并比较了它们的生物力学性能。
在网格收敛分析之后，我们建立了三组 1H-FNS、2H-FNS 和 LP-FNS。分别在髋关节中立、弯曲或伸展状态下，确定了骨折间间隙、滑动距离、剪切应力和压缩应力以及骨-植入物界面压缩应力、刚度和位移。还研究了植入物去除后股骨的应力和位移。
（1）三组 FNS 之间的 IFM 距离没有明显差异。然而，LP-FNS 组的旋转角度与传统 FNS 相比明显减小（中立位：1H-FNS，-61.64%；2H-FNS，-45.40%）。此外，髋关节中立、弯曲或伸展状态下最大骨-植入物界面压缩应力明显降低（1H-FNS：-6.47%、-20.59%或-4.49%；2H-FNS：-3.11%、16.70%或-7.03%）。（2）植入物去除后，三组之间的最大位移无明显差异，但最大 von Mises 应力在 LP-FNS 和 1H-FNS 组之间存在明显差异（-15.27%），除了 LP-FNS 和 2H-FNS 组之间的差异（-4.57%）。
LP-FNS 不仅可以提供与 1H-FNS 和 2H-FNS 相同的生物力学稳定性，而且在髋关节中立位、骨-植入物界面压缩应力和植入物去除后，在旋转阻力方面具有更大的优势。此外，1H-FNS 和 2H-FNS 的生物力学稳定性相似，除了植入物去除后的最大 von Mises 应力。LP-FNS 去除后的股骨不仅受到的应力相对较小，而且最小化了应力集中区域。
