Department of Orthopaedic Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, China.
Key Laboratory of Biomechanics of Hebei Province, Shijiazhuang, China.
Orthop Surg. 2021 Jul;13(5):1513-1520. doi: 10.1111/os.12973. Epub 2021 Jun 2.
To using finite element analysis to investigate the effects of the traditional titanium alloy Gamma nail and a biodegradable magnesium alloy bionic Gamma nail for treating intertrochanteric fractures.
Computed tomography images of an adult male volunteer of appropriate age and in good physical condition were used to establish a three-dimensional model of the proximal femur. Then, a model of a type 31A1 intertrochanteric fracture of the proximal femur was established, and the traditional titanium alloy Gamma nails and biodegradable magnesium alloy bionic Gamma nails were used for fixation, respectively. The von Mises stress, the maximum principal stress, and the minimum principal stress were calculated to evaluate the effect of bone ingrowth on stress distribution of the proximal femur after fixation.
In the intact model, the maximum stress was 5.8 MPa, the minimum stress was -11.7 MPa, and the von Mises stress was 11.4 MPa. The maximum principal stress distribution of the cancellous bone in the intact model appears in a position consistent with the growth direction of the principal and secondary tensile zones. After traditional Gamma nail healing, the maximum stress was 32 MPa, the minimum stress was -23.5 MPa, and the von Mises stress was 31.3 MPa. The stress concentration was quite obvious compared with the intact model. It was assumed that the nail would biodegrade completely within 12 months postoperatively. The maximum stress was 18.7 MPa, the minimum stress was -12.6 MPa, and the von Mises stress was 14.0 MPa. For the minimum principal stress, the region of minimum stress value less than -10 MPa was significantly improved compared with the traditional titanium alloy Gamma nail models. Meanwhile, the stress distribution of the bionic Gamma nail model in the proximal femur was closer to that of the intact bone, which significantly reduced the stress concentration of the implant.
The biodegradable magnesium alloy bionic Gamma nail implant can improve the stress distribution of fractured bone close to that of intact bone while reducing the risk of postoperative complications associated with traditional internal fixation techniques, and it has promising clinical value in the future.
使用有限元分析研究传统钛合金 Gamma 钉和可生物降解镁合金仿生 Gamma 钉治疗股骨转子间骨折的效果。
利用年龄和身体状况适宜的成年男性志愿者的计算机断层扫描图像，建立了近端股骨的三维模型。然后，建立了 31A1 型股骨转子间骨折模型，分别采用传统钛合金 Gamma 钉和可生物降解镁合金仿生 Gamma 钉固定。计算 von Mises 应力、最大主应力和最小主应力，以评估固定后骨内生长对近端股骨应力分布的影响。
在完整模型中，最大应力为 5.8 MPa，最小应力为-11.7 MPa，von Mises 应力为 11.4 MPa。完整模型的松质骨最大主应力分布出现在与主拉伸区和次拉伸区生长方向一致的位置。传统 Gamma 钉愈合后，最大应力为 32 MPa，最小应力为-23.5 MPa，von Mises 应力为 31.3 MPa。与完整模型相比，应力集中非常明显。假设术后 12 个月内钉完全降解。最大应力为 18.7 MPa，最小应力为-12.6 MPa，von Mises 应力为 14.0 MPa。对于最小主应力，与传统钛合金 Gamma 钉模型相比，低于-10 MPa 的最小主应力值区域显著改善。同时，仿生 Gamma 钉模型在近端股骨中的应力分布更接近完整骨，显著降低了植入物的应力集中。
可生物降解镁合金仿生 Gamma 钉植入物可以改善骨折骨的应力分布，使其更接近完整骨，同时降低与传统内固定技术相关的术后并发症风险，具有广阔的临床应用前景。
