Terry Michael A, Winell Jennifer J, Green Daniel W, Schneider Robert, Peterson Margaret, Marx Robert G, Widmann Roger F
Hospital for Special Surgery, Weill Medical College of Cornell University, New York, New York, USA.
J Pediatr Orthop. 2005 Mar-Apr;25(2):197-201. doi: 10.1097/01.bpo.0000148496.97556.9f.
The purpose of this study was to assess interobserver and intraobserver variability in the assessment of clinical and radiographic measurement of lower limb length discrepancy. Clinical measurements included direct measurement with a tape measure from anterior superior iliac spine (ASIS) to lateral malleolus and ASIS to medial malleolus as well as block measurement. Slit scanogram radiographic measurement was also evaluated. All three clinical measurements had excellent reliability, but the relatively large mean differences and the large 95% confidence intervals for clinical measurements limit the usefulness of these techniques. Slit scanogram measurement was the most reliable measurement technique. The intraobserver variance of direct slit scanogram measurement included intraclass correlation coefficient of 0.99, mean difference of 0.1 cm, and 95% confidence interval of 0.4 cm. Results were not influenced by patient age or body mass index. Slit scanogram measurement is the preferred method for assessment of limb length discrepancy. The direct slit scanogram measurement described in the text follows the mechanical axis line of the leg in the "at ease" standing position described by Paley. Direct measurement using a measuring tape on a full-length slit scanogram is more reliable than indirect measurement using horizontal lines drawn to a radiolucent ruler that is positioned by a technician, since direct measurement avoids errors due to nonparallel positioning of the limb relative to the ruler, and direct measurement also avoids errors due to non-horizontal lines drawn from standard bony landmarks to the ruler. The ideal radiographic measurement technique would have high reliability and accuracy and would minimize or eliminate radiation.
本研究的目的是评估观察者间和观察者内下肢长度差异临床及影像学测量评估中的变异性。临床测量包括用卷尺从前上棘（ASIS）到外踝以及从ASIS到内踝的直接测量以及分段测量。还评估了裂隙扫描X线片测量。所有三种临床测量均具有出色的可靠性，但临床测量相对较大的平均差异和较大的95%置信区间限制了这些技术的实用性。裂隙扫描X线片测量是最可靠的测量技术。直接裂隙扫描X线片测量的观察者内方差包括组内相关系数为0.99、平均差异为0.1厘米以及95%置信区间为0.4厘米。结果不受患者年龄或体重指数的影响。裂隙扫描X线片测量是评估肢体长度差异的首选方法。文中所述的直接裂隙扫描X线片测量遵循佩利描述的“自然放松”站立位时腿部的机械轴线。在全长裂隙扫描X线片上使用卷尺进行直接测量比由技术人员放置的不透射线标尺绘制水平线进行间接测量更可靠，因为直接测量避免了由于肢体相对于标尺的不平行定位导致的误差，并且直接测量还避免了从标准骨性标志到标尺绘制的非水平线导致的误差。理想的影像学测量技术应具有高可靠性和准确性，并能使辐射最小化或消除。
