Children's Hospital of Orange County, Orange, CA.
Department of Orthopedic Surgery, Riverside University Health System, 26520 Cactus Ave, Moreno Valley, CA 92555.
AJR Am J Roentgenol. 2021 Jul;217(1):172-176. doi: 10.2214/AJR.20.23358. Epub 2021 Apr 28.
In children (4 months to 8 years old), radiographic measurements of the acetabular index are the preferred method to assess developmental hip dysplasia. However, the acetabular index has been criticized as having variable reliability owing to difficulty identifying the correct anatomic landmarks. An alternative method of measuring the acetabular index using the ischium is being proposed to avoid the variability of the triradiate cartilage line as a reference point. With the alternative method, the acetabular index is derived by measuring the angle between a line connecting the ischial tuberosi-ties and a line connecting the inferomedial and superolateral edges of the acetabulum. The purpose of this study was to evaluate the accuracy and reliability of this alternative method of measuring the acetabular index compared with the traditional method. Children 4 months to 8 years old who presented for evaluation of developmental dysplasia of the hip were included. Two physicians, each using both the traditional and the alternative method, measured acetabular indexes on all radiographs. Accuracy was defined as mean absolute error less than 6°. Reliability was calculated by means of intraclass correlation coefficient (ICC). Pelvic radiographs of 40 children (324 hips) were included. The mean age was 23.7 months (range, 4-96 months) and mean acetabular index was 24.2° (range, 8-50°). The alternative method was associated with mean absolute error of 2.50°, which is significantly below the threshold of 6° ( < 0.001). Intrarater reliability for the traditional method was high (ICC, 0.81) and for the alternative method was very high (ICC, 0.92). Interrater reliability for the traditional method was high (ICC, 0.89) and for the alternative method was very high (ICC, 0.91). Measuring the acetabular index using the alternative method has very high accuracy and intrarater and interrater reliability.
在儿童（4 个月至 8 岁）中，髋臼指数的放射学测量是评估发育性髋关节发育不良的首选方法。然而，髋臼指数由于难以识别正确的解剖标志，其可靠性受到了批评。目前提出了一种使用坐骨测量髋臼指数的替代方法，以避免将三射线软骨线作为参考点的可变性。在替代方法中，髋臼指数通过测量连接坐骨结节的线与连接髋臼内下和外上边缘的线之间的角度来获得。本研究的目的是评估与传统方法相比，这种替代测量髋臼指数方法的准确性和可靠性。
研究纳入了因发育性髋关节发育不良就诊的 4 个月至 8 岁儿童。两位医生分别使用传统方法和替代方法测量了所有 X 线片的髋臼指数。准确性定义为平均绝对误差小于 6°。可靠性通过组内相关系数（ICC）进行计算。
纳入了 40 名儿童（324 髋）的骨盆 X 线片。平均年龄为 23.7 个月（范围 4-96 个月），平均髋臼指数为 24.2°（范围 8-50°）。替代方法的平均绝对误差为 2.50°，明显低于 6°的阈值（<0.001）。传统方法的组内信度很高（ICC，0.81），替代方法的组内信度非常高（ICC，0.92）。传统方法的组间信度很高（ICC，0.89），替代方法的组间信度非常高（ICC，0.91）。
使用替代方法测量髋臼指数具有非常高的准确性和组内及组间信度。
