Department of Orthopedics, Huangshi Central Hospital, Affiliated Hospital of Hubei Polytechnic University, Huangshi, Hubei, China.
Medicine (Baltimore). 2023 May 19;102(20):e33816. doi: 10.1097/MD.0000000000033816.
We aimed to establish a model of type II avulsion fractures of the calcaneal tuberosity treated with 2 hollow screws implanted in different directions and to analyze the biomechanical properties of the model using the finite element method. The Dicom data of the calcaneal bone obtained after computed tomography scan were inputted into Mimics 21.0 software and Geomagic Studio software to generate a 3D finite element digital model of the calcaneal bone. The model was then imported into SOLIDWORKS 2020 software. Based on the Beavis theory, the calcaneal bone was cut to build a type II avulsion fracture model of the calcaneal tuberosity; the calcaneal fracture was then simulated by internal fixation using hollow screws. Two screws were used to fix the calcaneal bone from the calcaneal tuberosity in different ways, resulting in 3 different calcaneal models (Model 1 involved 2 screws for fixing the fracture vertically; Model 2 had 2 screws for fixing the fracture cross-wise; and Model 3 had 2 screws for fixing the fracture parallelly). Three internal fixation models were loaded under the same conditions, and lines finite element analysis was then performed to calculate the stress distribution of the generated internal fixation models. Under the same loading conditions, compared with Models 2 and 3, Model 1 exhibited smaller maximum displacement values of the heel bone, maximum equivalent force values of the screws, and more dispersed stresses. Avulsion fractures of the calcaneal tuberosity can be treated using 2 screws to fix the fracture vertically (Model 1), which is more biomechanically relevant.
建立跟骨结节Ⅱ型撕脱骨折模型，采用 2 枚不同方向空心螺钉固定，并用有限元法分析模型的生物力学性能。将跟骨 CT 扫描后获得的 Dicom 数据输入 Mimics21.0 软件和 Geomagic Studio 软件，生成跟骨三维有限元数字模型。将模型导入 SOLIDWORKS2020 软件。基于 Beavis 理论，对跟骨进行切割，建立跟骨结节Ⅱ型撕脱骨折模型；然后采用空心螺钉内固定模拟跟骨骨折。用 2 枚螺钉从跟骨结节处不同方向固定跟骨，制作 3 种不同的跟骨模型（模型 1：2 枚螺钉垂直固定骨折；模型 2：2 枚螺钉交叉固定骨折；模型 3：2 枚螺钉平行固定骨折）。在相同条件下对 3 种内固定模型进行加载，然后进行线有限元分析，计算生成的内固定模型的应力分布。在相同的加载条件下，与模型 2 和模型 3 相比，模型 1 的跟骨最大位移值、螺钉最大等效力值较小，且应力分布更分散。跟骨结节撕脱骨折可采用 2 枚螺钉垂直固定骨折（模型 1）进行治疗，更符合生物力学要求。
