Department of General, Trauma and Reconstructive Surgery, University Hospital LMU Munich, Marchioninistraße 15, 81377, Munich, Germany.
Statistical Consulting Unit, StabLab, Department of Statistics, LMU Munich, Munich, Germany.
BMC Musculoskelet Disord. 2021 Jun 26;22(1):590. doi: 10.1186/s12891-021-04452-w.
The treatment of tibial fractures with an intramedullary nail is an established procedure. However, torsional control remains challenging using intraoperatively diagnostic tools. Radiographic tools such as the Cortical Step Sign (CSS) and the Diameter Difference Sign (DDS) may serve as tools for diagnosing a relevant malrotation. The aim of this study was to investigate the effect of torsional malalignment on CSS and DDS parameters and to construct a prognostic model to detect malalignment.
A proximal tibial shaft fracture was set in human tibiae. Torsion was set stepwise from 0° to 30° in external and internal torsion. Images were obtained with a C-arm and transferred to a PC for measuring the medical cortical thickness (MCT), lateral cortical thickness (LCT), tibial diameter (TD) in AP and the anterior cortical thickness (ACT) as well as the posterior cortical thickness (PCT) and the transverse diameter (TD) of the proximal and the distal main fragment.
There were significant differences between the various degrees of torsion for each of the absolute values of the examined variables. The parameters with the highest correlation were TD, LCT and ACT. A model combining ACT, LCT, PCT and TD lateral was most suitable model in identifying torsional malalignment. The best prediction of clinically relevant torsional malalignment, namely 15°, was obtained with the TD and the ACT.
This study shows that the CSS and DDS are useful tools for the intraoperative detection of torsional malalignment in proximal tibial shaft fractures and should be used to prevent maltorsion.
髓内钉治疗胫骨骨折是一种成熟的手术方法。然而，术中诊断工具在控制扭转方面仍然具有挑战性。影像学工具，如皮质台阶征（CSS）和直径差征（DDS），可以作为诊断相关旋转移位的工具。本研究旨在探讨扭转对线不良对 CSS 和 DDS 参数的影响，并构建一种预测模型来检测对线不良。
在人体胫骨上设置胫骨骨干近端骨折。从 0°到 30°，依次向内外扭转设置扭转。使用 C 臂机获得图像，并传输到 PC 上，以测量医学皮质厚度（MCT）、外侧皮质厚度（LCT）、前后皮质厚度（ACT）以及胫骨直径（TD）在 AP 和近端和远端主骨块的前后皮质厚度（PCT）和横径（TD）。
在每个检查变量的绝对值中，各扭转度之间存在显著差异。相关性最高的参数是 TD、LCT 和 ACT。将 ACT、LCT、PCT 和 TD 侧联合起来的模型是最适合识别扭转对线不良的模型。最佳预测临床相关扭转对线不良，即 15°，是通过 TD 和 ACT 获得的。
本研究表明，CSS 和 DDS 是术中检测胫骨骨干近端骨折扭转对线不良的有用工具，应加以利用以防止扭转不良。
