Komatsu Motoharu, Iwami Takehiro, Kijima Hiroaki, Kawano Tetsuya, Miyakoshi Naohisa
Graduate School of Engineering Science, Akita University, Japan.
Department of Orthopedic Surgery, Akita University Graduate School of Medicine, Akita, Japan.
J Clin Orthop Trauma. 2022 Sep 20;34:102015. doi: 10.1016/j.jcot.2022.102015. eCollection 2022 Nov.
The objectives of this study are 1) to biomechanically compare six different intramedullary fixations for basicervical fracture (AO 31-B3, Type 2 in area classification) and transcervical shear fracture (AO 31-B2.3, Type 1-2 in area classification) using the finite element (FE) method, and 2) to investigate the effects of two different unstable fracture types on fixation.
FE models of two different types of proximal femoral fractures are constructed from CT scan images of a patient with osteoporosis. The fracture models are fixed with a short femoral nail with a single lag screw, short femoral nail with a single blade, and short femoral nail with double lag screws, and then fixed with long femoral nails for each of the three nail types. Subsequently, the maximum loads during walking and stair climbing, as well as the minimum principal strain and compressive failure elements are calculated to assess the fixation of each implant.
In both fracture types, the long nail with double lag screws show the smallest volume of compressive failure elements (basicervical fracture, 2 mm; transcervical shear fracture, 217 mm). In all types of implants, the volume of the compressive failure elements is larger in the transcervical shear fracture than in the basicervical fracture. A similar trend is observed for the minimum principal strain (compressive strain).
The present study shows that a long nail with double lag screws is the most fixative intramedullary nail device for basicervical fracture and transcervical shear fracture in any condition. Furthermore, it is shown that transcervical shear fracture is considerably more unstable than basicervical fracture.
本研究的目的是：1）使用有限元（FE）方法对六种不同的髓内固定方法治疗股骨粗隆下骨折（AO 31-B3，区域分类中的2型）和经颈剪切骨折（AO 31-B2.3，区域分类中的1-2型）进行生物力学比较；2）研究两种不同不稳定骨折类型对固定的影响。
从一名骨质疏松症患者的CT扫描图像构建两种不同类型的股骨近端骨折的有限元模型。骨折模型分别用带单枚拉力螺钉的短股骨钉、带单枚刀片的短股骨钉和带双枚拉力螺钉的短股骨钉固定，然后对这三种钉子类型分别用长股骨钉固定。随后，计算行走和爬楼梯时施加的最大负荷，以及最小主应变和压缩破坏单元，以评估每种植入物的固定情况。
在两种骨折类型中，带双枚拉力螺钉的长钉的压缩破坏单元体积最小（股骨粗隆下骨折为2mm；经颈剪切骨折为217mm）。在所有类型的植入物中，经颈剪切骨折的压缩破坏单元体积大于股骨粗隆下骨折。最小主应变（压缩应变）也观察到类似趋势。
本研究表明，在任何情况下，带双枚拉力螺钉的长钉是治疗股骨粗隆下骨折和经颈剪切骨折最具固定作用的髓内钉装置。此外，研究表明经颈剪切骨折比股骨粗隆下骨折明显更不稳定。
