Trauma Emergency Center, Key Laboratory of Biomechanics and Orthopaedic Research Institute of Hebei Province, The Third Hospital of Hebei Medical University, No.139 Ziqiang Road, Shijiazhuang, 050051, Hebei, People's Republic of China.
School of Medicine, Nankai University, Tianjin, 300071, People's Republic of China.
J Orthop Surg Res. 2021 Aug 18;16(1):511. doi: 10.1186/s13018-021-02665-2.
Cannulated screws (CS) are one of the most widely used treatments for femoral neck fracture, however, associated with high rate of complications. In this study, we designed a new type of cannulated screws called degradable magnesium alloy bionic cannulated screws (DMBCS) and our aim was to compare the biomechanical properties of DMBCS, the traditionally used titanium alloy bionic cannulated screws (TBCS) and titanium alloy cannulated screws (TTCS).
A proximal femur model was established based on CT data of a lower extremity from a voluntary healthy man. Garden type III femoral neck fracture was constructed and fixed with DMBCS, TBCS, and TTCS, respectively. Biomechanical effect which three type of CS models have on femoral neck fracture was evaluated and compared using von Mises stress distribution and displacement.
In the normal model, the maximum stress value of cortical bone and cancellous bone was 76.18 and 6.82 MPa, and the maximum displacement was 5.52 mm. Under 3 different fracture healing status, the stress peak value of the cortical bone and cancellous bone in the DMBCS fixation model was lower than that in the TTCS and TBCS fixation, while the maximum displacement of DMBCS fixation model was slightly higher than that of TTCS and TBCS fixation models. As the fracture heals, stress peak value of the screws and cortical bone of intact models are decreasing, while stress peak value of cancellous bone is increasing initially and then decreasing.
The DMBCS exhibits the superior biomechanical performance than TTCS and TBCS, whose fixation model is closest to the normal model in stress distribution. DMBCS is expected to reduce the rates of post-operative complications with traditional internal fixation and provide practical guidance for the structural design of CS for clinical applications.
空心螺钉（CS）是治疗股骨颈骨折最常用的方法之一，但相关并发症发生率较高。本研究设计了一种新型的空心螺钉，称为可降解镁合金仿生空心螺钉（DMBCS），旨在比较 DMBCS、传统使用的钛合金仿生空心螺钉（TBCS）和钛合金空心螺钉（TTCS）的生物力学性能。
基于一名自愿健康男性下肢的 CT 数据建立了一个近侧股骨模型。构建 Garden 型 III 股骨颈骨折，分别用 DMBCS、TBCS 和 TTCS 固定。使用 von Mises 应力分布和位移评估和比较三种 CS 模型对股骨颈骨折的生物力学效应。
在正常模型中，皮质骨和松质骨的最大应力值分别为 76.18 和 6.82 MPa，最大位移为 5.52 mm。在 3 种不同骨折愈合状态下，DMBCS 固定模型皮质骨和松质骨的峰值应力值均低于 TTCS 和 TBCS 固定模型，而 DMBCS 固定模型的最大位移略高于 TTCS 和 TBCS 固定模型。随着骨折愈合，完整模型中螺钉和皮质骨的峰值应力值逐渐降低，而松质骨的峰值应力值先增加后降低。
DMBCS 的生物力学性能优于 TTCS 和 TBCS，其固定模型在应力分布上最接近正常模型。DMBCS 有望降低传统内固定术后并发症的发生率，并为临床应用的 CS 结构设计提供实用指导。
