Christersson Albert, Nysjö Johan, Berglund Lars, Malmberg Filip, Sintorn Ida-Maria, Nyström Ingela, Larsson Sune
Department of Orthopaedics, Uppsala University, S-751 85, Uppsala, Sweden.
Centre for Image Analysis, Uppsala University, Uppsala, Sweden.
Skeletal Radiol. 2016 Jun;45(6):763-9. doi: 10.1007/s00256-016-2350-6. Epub 2016 Feb 27.
The aim of the present study was to compare the reliability and agreement between a computer tomography-based method (CT) and digitalised 2D radiographs (XR) when measuring change in dorsal angulation over time in distal radius fractures.
Radiographs from 33 distal radius fractures treated with external fixation were retrospectively analysed. All fractures had been examined using both XR and CT at six times over 6 months postoperatively. The changes in dorsal angulation between the first reference images and the following examinations in every patient were calculated from 133 follow-up measurements by two assessors and repeated at two different time points. The measurements were analysed using Bland-Altman plots, comparing intra- and inter-observer agreement within and between XR and CT.
The mean differences in intra- and inter-observer measurements for XR, CT, and between XR and CT were close to zero, implying equal validity. The average intra- and inter-observer limits of agreement for XR, CT, and between XR and CT were ± 4.4°, ± 1.9° and ± 6.8° respectively.
For scientific purpose, the reliability of XR seems unacceptably low when measuring changes in dorsal angulation in distal radius fractures, whereas the reliability for the semi-automatic CT-based method was higher and is therefore preferable when a more precise method is requested.
本研究的目的是比较基于计算机断层扫描的方法（CT）和数字化二维X线片（XR）在测量桡骨远端骨折背侧成角随时间变化时的可靠性和一致性。
回顾性分析33例接受外固定治疗的桡骨远端骨折的X线片。所有骨折在术后6个月内均进行了6次XR和CT检查。由两名评估者从133次随访测量中计算出每位患者首次参考图像与后续检查之间的背侧成角变化，并在两个不同时间点重复进行。使用Bland-Altman图分析测量结果，比较XR和CT内部及之间的观察者内和观察者间一致性。
XR、CT以及XR与CT之间观察者内和观察者间测量的平均差异接近零，意味着有效性相同。XR、CT以及XR与CT之间观察者内和观察者间的平均一致性界限分别为±4.4°、±1.9°和±6.8°。
出于科学目的，在测量桡骨远端骨折背侧成角变化时，XR的可靠性似乎低得令人无法接受，而基于半自动CT的方法可靠性更高，因此在需要更精确方法时更可取。
