Department of Mechanical Engineering, Temple University, Philadelphia, PA 19122, USA.
Injury. 2012 Jul;43(7):1159-65. doi: 10.1016/j.injury.2012.03.015. Epub 2012 Apr 5.
Headless Compression Screws (HCS) are commonly utilized for the fixation of small bone and articular fractures. Recently several new second generation HCS (SG-HCS) have been introduced with the purported benefits of improved biomechanical characteristics. We sought to determine and compare the biomechanical efficiencies of these screws.
Five HCS including four second generation (Mini-Acutrak 2 (Acumed), Twinfix (Stryker), Kompressor Mini (Integra), HCS 3.0 (Synthes)) and one first generation (Herbert-Whipple) were studied. Polyurethane foam blocks that represented osteoporotic cancellous bone (0.16 g/cc) with a simulated transverse fracture at the waist were utilized and five screws of each brand were tested for the generated compression force and fastening torque during insertion with and without pre-drilling.
The generated compression force was highest for Mini-Acutrak 2 (45.41 ± 0.88 N) and lowest for Herbert-Whipple (13.44 ± 2.35 N) and forces of Twinfix, Kompressor Mini, HCS 3.0 were in between in descending order. The compression force of SG-HCS increased slightly without pre-drilling but it was not statistically significant while the fastening torque increased significantly. Slight over-fastening beyond the recommended stage significantly reduced the compression force in Twinfix and Kompressor and had no or moderate effect in other screws.
All SG-HCS demonstrated greater biomechanical characteristics than the first generation Herbert-Whipple screw. The Mini-Acutrak 2 with a variable pitch design generated the maximum compression force and showed the most reliability and sustainability. Screws with independently rotating trailing heads (Twinfix and Kompressor Mini) demonstrated loss of compression with extra turns. The increase of fastening torque due to over-fastening and loss of compression at the same time in some screw designs, demonstrated how the fastening torque (applied by the surgeon) can be a misleading measure of the compression force. Application of SG-HCS in osteoporotic bone without pre-drilling can slightly increase the compression force.
无头加压螺丝钉（HCS）常用于固定小骨和关节骨折。最近，几种新型第二代 HCS（SG-HCS）已经问世，据称具有改善生物力学特性的优势。我们旨在确定和比较这些螺丝钉的生物力学效率。
研究了五种 HCS，包括四种第二代（Acumed 的 Mini-Acutrak 2、Stryker 的 Twinfix、Integra 的 Kompressor Mini、Synthes 的 HCS 3.0）和一种第一代（Herbert-Whipple）。使用代表骨质疏松松质骨（0.16 g/cc）的聚氨酯泡沫块，在腰部模拟横断骨折，每种品牌的 5 个螺丝钉分别进行了不带预钻孔和带预钻孔时的加压力和紧固扭矩测试。
Mini-Acutrak 2 的加压力最高（45.41 ± 0.88 N），Herbert-Whipple 的最低（13.44 ± 2.35 N），Twinfix、Kompressor Mini 和 HCS 3.0 的加压力依次降低。SG-HCS 的加压力在不带预钻孔时略有增加，但无统计学意义，而紧固扭矩显著增加。在推荐阶段过度紧固会显著降低 Twinfix 和 Kompressor 的加压力，而对其他螺丝钉的影响较小或适度。
所有 SG-HCS 均表现出优于第一代 Herbert-Whipple 螺丝钉的生物力学特性。具有可变螺距设计的 Mini-Acutrak 2 产生最大的加压力，表现出最高的可靠性和可持续性。具有独立旋转尾端的螺丝钉（Twinfix 和 Kompressor Mini）显示出额外的旋转会导致加压力损失。由于过度紧固导致紧固扭矩增加以及一些螺丝钉设计同时出现加压力损失，表明紧固扭矩（由外科医生施加）可能是加压力的误导性测量。在骨质疏松性骨中应用 SG-HCS 而不带预钻孔可略微增加加压力。
