Gillette Children's Specialty Healthcare, St. Paul, MN 55101, USA.
Gillette Children's Specialty Healthcare, St. Paul, MN 55101, USA.
Gait Posture. 2023 Feb;100:126-131. doi: 10.1016/j.gaitpost.2022.12.008. Epub 2022 Dec 9.
Assessments of lower limb torsion are ubiquitous in clinical gait analysis practice as pathologic lower limb rotational deformity may contribute to gait abnormalities, anterior knee pain, as well as other debilitating conditions. Understandably, the overall utility of any torsional assessment is dependent on the measurement method's intrinsic accuracy, precision, and robustness to clinical interference factors. Recently, biplanar radiography (BPR) measurements of torsion have been shown to be both accurate and precise, but the robustness of BPR to potential interference factors is unknown.
How robust are BPR lower limb torsional assessments to six potential interference factors: amount of torsion, skeletal maturity, radiograph quality, prior osteotomy, presence of implants, and observer training background and experience?
In this retrospective cohort study, four observers of diverse backgrounds and experience generated digital 3D reconstructions of 44 lower limbs using BPR images obtained during standard of care visits (age range 7-35 years). From each reconstruction, four lower limb torsional parameters were computed: femoral torsion, femorotibial rotation, tibial torsion, and transmalleolar axis equivalent. The mean absolute deviation (MAD) of each torsional parameter - calculated across the four observers - was used as the measure of reliability and tested against all interference factors.
Results demonstrated that the average MAD was 2.1 degrees for femoral torsion, 3.0 degrees for transmalleolar axis equivalent, 3.8 degrees for femorotibial rotation, and 4.7 degrees for tibial torsion. None of the six potential interference factors were found to systematically influence BPR reliability across all four torsional parameters. Of the factors found to statistically influence one or more torsional parameter, none affected MAD values to a clinically meaningful extent.
In addition to being accurate and precise, BPR appears to be robust to several clinical factors relevant to children and young adults with or at risk for pathological lower limb torsion.
在临床步态分析实践中，下肢扭转评估非常普遍，因为病理性下肢旋转畸形可能导致步态异常、前膝疼痛以及其他使人衰弱的病症。可以理解的是，任何扭转评估的整体效用都取决于测量方法的固有准确性、精度和对临床干扰因素的稳健性。最近，双平面放射摄影（BPR）的扭转测量已被证明既准确又精确，但 BPR 对潜在干扰因素的稳健性尚不清楚。
BPR 下肢扭转评估对六个潜在干扰因素的稳健性如何：扭转量、骨骼成熟度、射线照相质量、先前的截骨术、植入物的存在以及观察者的培训背景和经验？
在这项回顾性队列研究中，四位背景和经验各异的观察者使用 BPR 图像生成了 44 条下肢的数字 3D 重建，这些图像是在标准护理就诊期间获得的（年龄范围为 7-35 岁）。从每个重建中，计算了四个下肢扭转参数：股骨扭转、股骨胫骨旋转、胫骨扭转和踝间轴等效物。每个扭转参数的平均绝对偏差（MAD）-由四位观察者计算得出-用作可靠性的衡量标准，并针对所有干扰因素进行了测试。
结果表明，股骨扭转的平均 MAD 为 2.1 度，踝间轴等效物的平均 MAD 为 3.0 度，股骨胫骨旋转的平均 MAD 为 3.8 度，胫骨扭转的平均 MAD 为 4.7 度。六个潜在的干扰因素均未被发现系统地影响 BPR 在所有四个扭转参数中的可靠性。在所发现的会统计上影响一个或多个扭转参数的因素中，没有一个因素会对 MAD 值产生有临床意义的影响。
除了准确和精确之外，BPR 似乎对与病理性下肢扭转或有患病风险的儿童和年轻人相关的几个临床因素具有稳健性。
