背景:通常进行(患病的)踝关节的关节固定术以实现疼痛缓解和稳定性。关节固定术技术的一个基本原理包括表面的刚性固定直到结合。似乎合理的是,稳定的锚固和均匀的压力分布应该是有利的,然而,尚未调查。目的是实现均匀压缩,因为这有望为预期的关节固定术的骨融合产生有利的结果。具有不同生物力学概念的许多植入物可用于踝关节融合。在这项研究中,无头压紧螺钉(HCS,DePuySynthes,Zuchwil,瑞士)在生物力学上与替代固定系统进行了比较,IOFix装置(极端医疗,Parsippany,NJ,USA)inregardingtothedistributionofthecompressionforce(areaofcontact)andpeakcompressioninasawbonesondesis-model(Sawbones®PacificResearchLaboratories,Vashon,WA,美国)。这项研究旨在量化与IOFix相比,使用无头压缩螺钉可以获得的骨界面之间的接触面积。在当前的文学中,假设,骨骼之间具有足够压力的大接触面会带来良好的临床效果。然而,没有临床或生物力学研究,描述关节固定术的最佳压缩压力。
方法:将两个标准化的锯块放置在定制的夹具中。使用模板将IOFix和无头压缩螺钉彼此成对平行地插入,以形成均匀的钻孔图案。以0.5Nm的预定扭矩插入所有螺钉。位于两个锯块之间的压力传感器被压缩以测量峰值压缩力,压缩分布,接触面积。
结果:使用IOFix,与HCS螺钉的接触面积相比,压缩力分布在明显更大的面积上,导致整个关节固定术表面上更均匀的接触面积。最大压缩力无显著差异。
结论:IOFix系统将压缩压力分布在更大的区域,导致在表面上更均匀地分布压缩。临床研究必须表明这是否会导致较低的假关节发生率。
BACKGROUND: Arthrodesis of a (diseased) ankle joint is usually performed to achieve pain relief and stability. One basic principle of arthrodesis techniques includes rigid fixation of the surfaces until union. It seems plausible that stable anchoring and homogeneous pressure distribution should be advantageous, however, it has not been investigated yet. The aim is to achieve uniform compression, as this is expected to produce favorable results for the bony fusion of the intended arthrodesis. Numerous implants with different biomechanical concepts can be used for ankle fusion. In this study, headless compression screws (HCS, DePuy Synthes, Zuchwil, Switzerland) were compared biomechanically to an alternative fixation System, the IOFix device (Extremity Medical, Parsippany, NJ, USA) in regard to the distribution of the compression force (area of contact) and peak compression in a sawbone arthrodesis-model (Sawbones® Pacific Research Laboratories, Vashon, WA, USA). This study aims to quantify the area of contact between the bone interface that can be obtained using headless compression screws compared to the IOFix. In current literature, it is assumed, that a large contact surface with sufficient pressure between the bones brings good clinical results. However, there are no clinical or biomechanical studies, that describe the optimal compression pressure for an arthrodesis.
METHODS: Two standardized sawbone blocks were placed above each other in a custom-made jig. IOFix and headless compression screws were inserted pairwise parallel to each other using a template for a uniform drilling pattern. All screws were inserted with a predefined torque of 0.5 Nm. Pressure transducers positioned between the two sawbone blocks were compressed for the measurement of peak compression force, compression distribution, and area of contact.
RESULTS: With the IOFix, the compression force was distributed over significantly larger areas compared to the contact area of the HCS screws, resulting in a more homogenous contact area over the entire arthrodesis surface. Maximum compression force showed no significant difference.
CONCLUSIONS: The IOFix system distributes the compression pressure over a much larger area, resulting in more evenly spread compression at the surface. Clinical studies must show whether this leads to a lower pseudarthrosis rate.