Hornová Jana, Růžička Pavel, Hrubina Maroš, Šťastný Eduard, Košková Andrea, Fulín Petr, Gallo Jiří, Daniel Matej
Laboratory of Biomechanics, Faculty of Mechanical Engineering, Czech Technical University in Prague, Prague, Czech Republic.
Department of Orthopaedics, Hospital Pelhřimov, Pelhřimov, Czech Republic.
PLoS One. 2017 Nov 30;12(11):e0188743. doi: 10.1371/journal.pone.0188743. eCollection 2017.
Preoperative planning for total hip arthroplasty includes templating on anteroposterior radiographs. It is necessary to consider radiographic magnification in order to scale templates accurately. Studies dealing with hip templating report different values of radiographic magnification. It is not clear if the observed difference in magnification between the studies is caused by variability in studied groups, methodology or instrumentation. We hypothesize that there is a difference in magnification between clinical workplaces. Within this study, radiographic magnification was estimated on 337 radiographs of patients after total hip surgery from five orthopaedic departments in the Czech Republic. Magnification was determined for each patient as a ratio between diameter of implanted femoral head measured on radiogram and its true size. One-way ANOVA revealed significant differences in magnification between workplaces (F(4,332) = 132, p≤0.001). These results suggest that radiographic magnification depends on the workplace where it is taken or more precisely on radiographic device. It indicates potential limits in generalizability of results of studies dealing with preoperative planning accuracy to other institutions.
全髋关节置换术的术前规划包括在前后位X线片上进行模板测量。为了准确缩放模板，有必要考虑X线放大率。关于髋关节模板测量的研究报告了不同的X线放大率值。目前尚不清楚研究中观察到的放大率差异是由研究组、方法或仪器的变异性引起的。我们假设临床工作场所之间的放大率存在差异。在本研究中，对来自捷克共和国五个骨科科室的337例全髋关节置换术后患者的X线片进行了X线放大率估计。将每位患者的放大率确定为X线片上测量的植入股骨头直径与其真实尺寸的比值。单因素方差分析显示不同工作场所之间的放大率存在显著差异（F(4,332) = 132，p≤0.001）。这些结果表明，X线放大率取决于拍摄的工作场所，或者更准确地说取决于X线设备。这表明处理术前规划准确性的研究结果在推广到其他机构时可能存在局限性。
