基于三维CT影像判断桡尺远侧关节移位的临床研究

目的 建立一种测量桡尺远侧关节(DRUJ)径向移位的方法,且可用于尺骨正、负向变异者;获得DRUJ在掌、背向应力作用下径向移位的正常范围.方法 应力CT检查37侧正常DRUJ,于三维重建影像上,选取桡骨远侧关节面与侧方关节面交汇处的掌、背侧顶点及尺骨茎突下隐窝最凹陷处为参照点,即A、B、C三点,作A、B两点连线,过C点作AB垂线,交于D点,依次计算AD/AB、DB/AB比值;由2名手外科医师独立完成测量,其中1人进行复测,然后评价该方法可信度.结果 37侧正常DRUJ重建影像的AD/AB、DB/AB均值分别为0.39±0.07、0.37±0.07,正常值范围((-x)±2s)依次为0.25～0.50、0.23～0.50,二者差异无统计学意义(t=-1.400,P=0.170),同一移位方向的男性女性之间、左右侧手之间,同一性别、手别的背、掌侧移位之间差异均无统计学意义(P＞0.05).AD/AB、DB/AB观察者间相关系数(ICC)分别是0.84、0.80,观察者内ICC分别是0.93、0.92.结论 本法无论尺骨变异如何,均可测量DRUJ移位,且可重复性强、可信度好;AD/AB比值小于0.25或BD/AB小于0.23,可提示DRUJ不稳定.

A method of measuring the displacement of the distal radioulnar joint on the three-dimensional CT imaging

Objective To establish a clinical method for measuring the displacement of the distal radioulnar joint (DRUJ) precisely irrespective of ulnar variance, and to derive normal population translation references with parlmar and dorsal stress. Methods Thirty-seven normal distal forearms were scaned with computed tomography using an apparatus designed by Pirela-Cruz. Each extremity was scanned in two positions: maximal ulnar palmar and dorsal stress. The digital imaging and communications in medicine(DICOM) CT images were then imported into Mimics 10.0 for three-dimensional reconstruction. On the DRUJs 3D images, choose the most prominent point of the palmar and dorsal margins of the sigmoid notch and the excavate ulna fovea as the reference points A, B and C. A perpendicular line was then drawn from the point C to a line connecting points A and B with the intersection D. Calculate the ratio of AD/AB and DB/AB. Two observers measured all the DRUJs independently and one repeated the measurements one month later to determine the interobserver and intraobserver reliability. Results The mean ratio values of palmar (AD/AB) and dorsal ( DB/AB ) translation were 0.39 ± 0.07 and 0.37 ± 0.07, and the normal references ((-x)±2s) were from 0.25 to 0.50 and from 0.23 to 0.50, respectively. No significant differences were observed in terms of positions, genders and dominant hands. The intraclass correlation coefficient(ICC) values for interobserver and intraobserver reliability (DB/AB, AD/AB) were 0.84, 0.80, 0.93 and 0.92, respectively. Conclusions This new method could accurately measure the displacement of DRUJs with acceptable reliability, even with ulna positive or negative variance. Instability of DRUJ may be indicated when AD/AB is less than 0.25 or BD/AB is less than 0.23.