Steiner Juri A, Ferguson Stephen J, van Lenthe G Harry
Institute for Biomechanics, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland.
Institute for Biomechanics, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland.
Med Eng Phys. 2016 Apr;38(4):417-22. doi: 10.1016/j.medengphy.2016.01.006. Epub 2016 Feb 23.
Secure fracture fixation is still a major challenge in orthopedic surgery, especially in osteoporotic bone. While numerous studies have investigated the effect of implant loading on the peri-implant bone after screw insertion, less focus has been put on bone damage that may occur due to the screw insertion process itself. Therefore, the aim of this study was to localize and quantify peri-implant bone damage caused by screw insertion. We used non-invasive three-dimensional micro-computed tomography to scan twenty human femoral bone cores before and after screw insertion. After image registration of the pre- and post-insertion scans, changes in the bone micro-architecture were identified and quantified. This procedure was performed for screws with a small thread size of 0.3mm (STS, N=10) and large thread size of 0.6mm (LTS, N=10). Most bone damage occurred within a 0.3mm radial distance of the screws. Further bone damage was observed up to 0.6mm and 0.9 mm radial distance from the screw, for the STS and LTS groups, respectively. While a similar amount of bone damage was found within a 0.3mm radial distance for the two screw groups, there was significantly more bone damage for the LTS group than the STS group in volumes of interest between 0.3-0.6mm and 0.6-0.9 mm. In conclusion, this is the first study to localize and quantify peri-implant bone damage caused by screw insertion based on a non-invasive, three-dimensional, micro-CT imaging technique. We demonstrated that peri-implant bone damage already occurs during screw insertion. This should be taken into consideration to further improve primary implant stability, especially in low quality osteoporotic bone. We believe that this technique could be a promising method to assess more systematically the effect of peri-implant bone damage on primary implant stability. Furthermore, including peri-implant bone damage due to screw insertion into patient-specific in silico models of implant-bone systems could improve the accuracy of these models.
在骨科手术中，尤其是在骨质疏松性骨中，实现骨折的牢固固定仍然是一项重大挑战。尽管众多研究调查了螺钉植入后植入物加载对植入物周围骨的影响，但对于螺钉插入过程本身可能导致的骨损伤关注较少。因此，本研究的目的是定位并量化由螺钉插入引起的植入物周围骨损伤。我们使用非侵入性三维微计算机断层扫描技术，在螺钉插入前后对20个人类股骨骨芯进行扫描。在对插入前后的扫描图像进行配准后，识别并量化骨微结构的变化。该过程针对螺纹尺寸为0.3mm的小螺纹螺钉（STS，N = 10）和螺纹尺寸为0.6mm的大螺纹螺钉（LTS，N = 10）进行。大多数骨损伤发生在距螺钉0.3mm的径向距离内。对于STS组和LTS组，分别在距螺钉0.6mm和0.9mm的径向距离处观察到进一步的骨损伤。虽然在0.3mm径向距离内，两组螺钉造成的骨损伤量相似，但在0.3 - 0.6mm和0.6 - 0.9mm的感兴趣体积内，LTS组的骨损伤明显多于STS组。总之，这是第一项基于非侵入性三维微CT成像技术定位并量化由螺钉插入引起的植入物周围骨损伤的研究。我们证明了植入物周围骨损伤在螺钉插入过程中就已发生。在进一步提高初次植入物稳定性时应考虑到这一点，尤其是在低质量的骨质疏松性骨中。我们认为，该技术可能是一种有前景的方法，可更系统地评估植入物周围骨损伤对初次植入物稳定性的影响。此外，将螺钉插入导致的植入物周围骨损伤纳入植入物 - 骨系统的患者特异性计算机模拟模型中，可提高这些模型的准确性。
