Zeynalov Reşad, Ağır İsmail, Akgülle Ahmet Hamdi, Kocaoğlu Barış, Yalçın Mithat Selim
Clinic of Orthopaedics and Traumatology, Baku Medical Plaza Hospital, Baku, Azerbaycan.
Eur J Orthop Surg Traumatol. 2015 Jul;25(5):955-60. doi: 10.1007/s00590-014-1525-x. Epub 2014 Sep 12.
The aim of this study was to evaluate the holding strength of cannulated screw with multiple holes on threaded area, supported with PMMA in femoral head.
A total of 48 human femoral heads were divided into two groups after mineral density measurement with Q-CT. Seven-millimeter cannulated screws with multiple holes on threaded area supported with PMMA were used in the study group, while in the control group standard 7-mm cannulated screws were used. Each group was divided into three subgroups with eight femoral heads. Mineral density of each subgroup was equal to the other. Groups were compared in terms of pull-out, maximum extraction torque and cut-out.
In pull-out group, maximum holding strength (N) was measured, while axial pull-out of 0.5 mm/sec applied with Instron. Results showed meaningful significant difference (p < 0.011) between two groups. In cut-out group, femoral heads were placed into Instron and loading was started from 5 N at 2 mm per minute at first, and it was continued until a failure, at least 5 mm, of implant was observed. Results showed significant difference (p < 0.05) between two groups. In maximum extraction group, 4° per second reverse torque (Nm) was applied with torque meter. Highest torque value was measured during extraction time, and results showed very significant difference (p < 0. 001) between two groups.
The results of our new design of cannulated screw augmented with PMMA provided background data to clinical application.
本研究旨在评估在股骨头中，带多个孔的空心螺钉在螺纹区域并由聚甲基丙烯酸甲酯（PMMA）支撑时的把持力。
通过定量计算机断层扫描（Q-CT）测量矿物质密度后，将48个人类股骨头分为两组。研究组使用在螺纹区域带多个孔并由PMMA支撑的7毫米空心螺钉，而对照组使用标准的7毫米空心螺钉。每组分为三个亚组，每组八个股骨头。各亚组的矿物质密度彼此相等。比较两组的拔出力、最大拔出扭矩和穿出情况。
在拔出组中，使用英斯特朗公司的仪器以0.5毫米/秒的轴向拔出速度测量最大把持力（牛顿）。结果显示两组之间存在显著差异（p < 0.011）。在穿出组中，将股骨头放入英斯特朗公司的仪器中，首先以每分钟2毫米的速度从5牛顿开始加载，持续加载直至观察到植入物至少有5毫米的失效。结果显示两组之间存在显著差异（p < 0.05）。在最大拔出扭矩组中，使用扭矩计以每秒4°的反向扭矩（牛顿米）施加扭矩。在拔出过程中测量最高扭矩值，结果显示两组之间存在非常显著的差异（p < 0.001）。
我们新设计的由PMMA增强的空心螺钉的研究结果为临床应用提供了背景数据。
