两种股骨颈骨折内固定物的物理参数比较

Comparison of physical parameters of two internal fixation devices for femoral neck fractures

背景:3枚空心松质骨拉力螺钉内固定已经成为股骨颈骨折内固定的标准操作技术,但其并发症较多,改进内置物的设计是减少并发症的途径之一。课题组设计了一种新型的内固定物,即自锁空心加压防旋转刀片,并对其进行了一系列研究。目的:比较两种股骨颈骨折内固定物-自锁空心加压防旋转刀片与AO7.3mm空心钉的物理参数。设计、时间及地点:随机对照实验,于2008-04/07在北京大学人民医院创伤骨科实验室完成。材料:8对尸体骨来源于北京大学医学部解剖学教研室,自锁空心加压防旋转刀片由北京航空航天大学机械学院加工车间制作。方法:将8对尸体骨标本随机分为自锁空心加压防旋转刀片固定组和7.3mm空心钉固定组,于股骨颈最窄处截骨,制作经颈型股骨颈骨折模型,测定每个标本的骨折断面面积以及股骨头的体积。然后直视下复位骨折,按照预先设计的操作步骤分别应用自锁空心加压防旋刀片和AO7.3mm空心钉进行固定;在固定完毕后的X射线片上测定内固定物在股骨头内的深度,计算体积。主要观察指标:内置物截面积/骨折断面面积以及内置物体积/股骨头体积。结果:两组骨折断面面积、内置物截面积/骨折断面面积、股骨头体积比较差异均无显著性(P>0.05)。空心钉组内置物体积、内置物体积与股骨头体积的比值大于自锁空心加压防旋刀片组(P<0.05)。结论:与AO7.3mm空心钉相比,自锁空心加压防旋刀片固定股骨颈骨折,减小了内置物所占股骨头空间,减少了内置物的数量,明显简化了操作难度,创伤小,有可能替代空心松质骨拉力螺钉成为治疗股骨颈骨折的首选内固定物。

BACKGROUND： Percutaneous cannulated cancellous lag screws internal fixation is the most used method for the cases of femoral neck fractures. However, there are some complications. We designed a new internal fixation device, self-locking cannulated compression anti-rotation blade to improve the treatment effect of femoral neck fractures. OBJECTIVE： To compare the physical parameters of two internal fixation devices, self-locking cannulated compression anti-rotation blade and At 7.3-mm cannulated screw applied to femoral neck fractures. DESIGN, TIME AND SETTING： Randomized controlled experiment was performed at the Department of Orthopaedics and Traumatology Laboratory, Peking University People＇s Hospital from April to July 2008. MATERIALS： Eight pairs of cadaver femurs were from Anatomy Research Institute of Peking University Medical Department, and self-locking cannulated compression anti-rotation blade was made by Mechanology Institute, Beijing Aviation and Aerospace University. METHODS： Femoral neck fracture model was made by osteotomy on eight pairs of cadaver femur and randomly divided into two groups. Area of broken end and volume of femoral head were measured. Two groups of specimens were differently fixed by self-locking cannulated compression anti-rotation blade and At 7.3-mm cannulated screw under fluoroscopic guidance according to designed procedures. Depth of internal fixation device in femoral head was measured on X-ray after fixation, and volume of internal fixation device in femoral head were calculated. MAIN OUTCOME MEASURES： Ratio of area of cross-section of internal fixation device versus area of broken end, and ratio of volume of internal fixation versus volume of femoral head. RESULTS： Area of broken end, ratio of area of cross-section of internal fixation device versus area of broken end, and volume of femoral head were not significantly different between two groups （P 〉 0.05）, but ratio of volume of self-locking cannulated compression anti-rotation blade versus volume of femoral head was significantly less than At 7.3 mm cannulated screw （P 〈 0.05）. CONCLUSION： Compared with At 7.3-mm cannulated screw, self-locking cannulated compression anti-rotation blade in treating femoral neck fracture has many advantages, such as reduction of space of internal fixation device in femoral head, reduction of quantity of internal fixation device, and reduction of manipulation difficulty, minimal invasion, and may substitute At 7.3 mm cannulated cancellous lag screw to treat femoral neck fracture.