Department of Orthopedics and Trauma Surgery, Musculoskeletal University Center Munich (MUM), University Hospital, LMU Munich, Munich, Germany.
Department of Experimental Orthopedics, University Hospital Jena, Campus Eisenberg, Waldkliniken Eisenberg, Eisenberg, Germany.
J Orthop Surg Res. 2024 Aug 10;19(1):475. doi: 10.1186/s13018-024-04906-6.
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.
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.
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.
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.
通常，为了缓解疼痛和稳定关节，会对（患病的）踝关节进行融合术。关节融合技术的一个基本原则包括在愈合过程中对关节表面进行刚性固定。稳定的固定和均匀的压力分布似乎是有利的，但尚未进行研究。目的是实现均匀压缩，因为这有望为预期的关节融合产生有利的结果。许多具有不同生物力学概念的植入物可用于踝关节融合。在这项研究中，无头加压螺钉（HCS，DePuy Synthes，瑞士楚格维尔）与替代固定系统，IOFix 装置（Extremity Medical，新泽西州帕西帕尼）在压力分布（接触面）和骨融合模型（Sawbones® Pacific Research Laboratories，华盛顿州沃申）中的峰值压缩方面进行了生物力学比较。这项研究旨在量化使用无头加压螺钉与 IOfix 相比可获得的骨界面接触面积。在当前的文献中，假设骨骼之间具有较大的接触面积和足够的压力会带来良好的临床效果。但是，没有临床或生物力学研究描述关节融合的最佳压缩压力。
两个标准化的Sawbones 块彼此叠放在一个定制的夹具中。使用用于均匀钻孔模式的模板将 IOfix 和无头加压螺钉成对平行插入。所有螺钉均以 0.5 Nm 的预定义扭矩插入。定位在两个 Sawbones 块之间的压力传感器用于测量峰值压缩力，压缩分布和接触面积。
与 HCS 螺钉相比，IOFix 可使压缩力分布在更大的区域上，从而使整个融合表面的接触区域更加均匀。最大压缩力无显著差异。
IOFix 系统将压缩压力分布在更大的区域上，从而使表面的压缩更加均匀。临床研究必须表明这是否会导致假性关节融合率降低。
