Feng Xiaoreng, Qi Weichen, Fang Christian X, Lu William W, Leung Frankie K L, Chen Bin
Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China.
Department of Orthopaedics & Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
Bone Joint Res. 2021 Feb;10(2):105-112. doi: 10.1302/2046-3758.102.BJR-2020-0072.R2.
To draw a comparison of the pullout strengths of buttress thread, barb thread, and reverse buttress thread bone screws.
Buttress thread, barb thread, and reverse buttress thread bone screws were inserted into synthetic cancellous bone blocks. Five screw-block constructs per group were tested to failure in an axial pullout test. The pullout strengths were calculated and compared. A finite element analysis (FEA) was performed to explore the underlying failure mechanisms. FEA models of the three different screw-bone constructs were developed. A pullout force of 250 N was applied to the screw head with a fixed bone model. The compressive and tensile strain contours of the midsagittal plane of the three bone models were plotted and compared.
The barb thread demonstrated the lowest pullout strength (mean 176.16 N (SD 3.10)) among the three thread types. It formed a considerably larger region with high tensile strains and a slightly smaller region with high compressive strains within the surrounding bone structure. The reverse buttress thread demonstrated the highest pullout strength (mean 254.69 N (SD 4.15)) among the three types of thread. It formed a considerably larger region with high compressive strains and a slightly smaller region with high tensile strains within the surrounding bone structure.
Bone screws with a reverse buttress thread design will significantly increase the pullout strength. Cite this article: 2021;10(2):105-112.
比较支撑螺纹、倒刺螺纹和反向支撑螺纹骨螺钉的拔出强度。
将支撑螺纹、倒刺螺纹和反向支撑螺纹骨螺钉插入合成松质骨块中。每组五个螺钉 - 骨块结构在轴向拔出试验中测试至失效。计算并比较拔出强度。进行有限元分析（FEA）以探究潜在的失效机制。建立三种不同螺钉 - 骨结构的FEA模型。在固定骨模型的情况下，对螺钉头部施加250 N的拔出力。绘制并比较三种骨模型矢状面的压缩和拉伸应变等高线。
在三种螺纹类型中，倒刺螺纹的拔出强度最低（平均176.16 N（标准差3.10））。在周围骨结构中，它形成了一个相当大的高拉伸应变区域和一个稍小的高压缩应变区域。反向支撑螺纹在三种螺纹类型中拔出强度最高（平均254.69 N（标准差4.15））。在周围骨结构中，它形成了一个相当大的高压缩应变区域和一个稍小的高拉伸应变区域。
具有反向支撑螺纹设计的骨螺钉将显著提高拔出强度。引用本文：2021;10(2):105 - 112。
