Swami Vimarsha G, Liu Lei, Mabee Myles, Jaremko Jacob L
Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton - Canada.
Departmental of Biomedical Engineering, University of Alberta, Edmonton - Canada.
Hip Int. 2016 Nov 10;26(6):602-607. doi: 10.5301/hipint.5000393. Epub 2016 Oct 15.
Indices from 3-D ultrasound may have a role in developmental dysplasia of the hip (DDH) assessment, but require a way to determine spatial orientation relative to body axes. The lateral iliac wall angle is a potentially suitable reference axis in 3-D ultrasound. We sought to quantify normal values and variations of the infant iliac wall angle on radiography, and compare with computed tomography (CT).
Acetabular and lateral iliac angles were measured on frontal pelvic radiographs of 200 patients (400 hips, 183 with DDH) and coronal CT of 20 patients (40 hips) aged 0-12 months. Relationships among morphologic indices and demographics were assessed using linear regression, Welch's t-test, Pearson's correlation coefficient (r) and coefficients of variance (CoV). Reliability was assessed using intra-class correlation coefficients (ICC).
The radiographic iliac angle averaged 53.0° ± 7.7° (mean ± standard deviation; 95% CI, 38°-68°) in DDH vs. 56.2° ± 6.7° (95% CI, 43°-69°) in normal hips (p<0.001), correlated weakly with age (r = 0.25), and showed no inter-sex differences (p = 0.79). Inter-reader and intra-reader reliability were ICC = 0.946 and 0.965. CT iliac angle had mean difference 5.8° ± 6.2° (p<0.01), CoV = 10% and r = 0.68 vs. corresponding radiographs.
The radiographic infant lateral iliac wall angle has mean value 53-56° in dysplastic and normal hips with consistent range of variation approximately ±15°, was measured with high reliability, does not differ by sex, and is only slightly lower in the youngest infants. The iliac wall angle is an unbiased reference axis that may be suitable to establish general spatial orientation of 3-D hip ultrasound images.
三维超声指标可能在发育性髋关节发育不良（DDH）评估中发挥作用，但需要一种确定相对于身体轴线空间方向的方法。髂骨外侧壁角是三维超声中一个潜在合适的参考轴。我们试图量化婴儿髂骨壁角在X线片上的正常值和变异情况，并与计算机断层扫描（CT）进行比较。
对200例患者（400髋，其中183例为DDH）0至12个月龄的骨盆正位X线片以及20例患者（40髋）的冠状位CT测量髋臼角和髂骨外侧壁角。使用线性回归、韦尔奇t检验、皮尔逊相关系数（r）和变异系数（CoV）评估形态学指标与人口统计学之间的关系。使用组内相关系数（ICC）评估可靠性。
DDH患者的X线片髂骨角平均为53.0°±7.7°（均值±标准差；95%CI，38°-68°），正常髋关节为56.2°±6.7°（95%CI，43°-69°）（p<0.001），与年龄弱相关（r = 0.25），且无性别差异（p = 0.79）。阅片者间和阅片者内可靠性的ICC分别为0.946和0.965。与相应X线片相比，CT髂骨角平均差值为5.8°±6.2°（p<0.01），CoV = 10%，r = 0.68。
发育不良和正常髋关节中婴儿X线片髂骨外侧壁角的平均值为53 - 56°，变异范围一致，约为±15°，测量可靠性高，无性别差异，且在最小的婴儿中仅略低。髂骨壁角是一个无偏参考轴，可能适合用于确定三维髋关节超声图像的一般空间方向。
