Gait Laboratory, Central Remedial Clinic, Clontarf, Dublin 3, Ireland.
Gait Laboratory, Central Remedial Clinic, Clontarf, Dublin 3, Ireland.
J Biomech. 2019 Jul 19;92:155-161. doi: 10.1016/j.jbiomech.2019.05.034. Epub 2019 May 24.
Centre of Pressure (CoP) location error is common when using kinematic and kinetic data to predict intersegmental forces and net joint moments during gait. Changes in peak moments due to CoP error have been reported in the literature. However, debate exists as to what levels of error are acceptable. The aim of this study was to examine the impact of CoP error on the kinetic profiles of children with typical development (TD) and children with cerebral palsy (CP) during gait. Three-dimensional kinematic and kinetic data were recorded and simulated CoP errors were applied at 3 mm, 6 mm, 9 mm, 12 mm increments in both positive and negative anteroposterior and mediolateral directions. Absolute differences in maximum kinetic parameters between increments were assessed in conjunction with changes in the Gait Deviation Index-Kinetic (GDI-Kinetic). Changes in GDI-Kinetic above 3.6 points were considered clinically significant. Maximum peak changes of up to 24.8% (CP) and 34.7% (TD) (sagittal plane) and up to 36.8% (CP) and 61.5% (TD) (coronal plane) were demonstrated at the knee. While absolute percentage differences were high at some error increments, GDI-Kinetic results suggested that such large percentage differences may still be clinically acceptable. Children with TD demonstrated clinically significant changes in GDI-Kinetic for CoP displacements of 9 mm and 12 mm, corresponding to 23% and 35% absolute differences in maximum moments. In contrast, the clinically significant threshold was not reached for children with CP that may be related to a slower walking speed. The findings of this study highlight the need for laboratories to consider the thresholds currently used for CoP error, which will help guide quality assurance procedures.
当使用运动学和动力学数据预测步态中的节段间力和净关节力矩时，中心压力（CoP）位置误差很常见。文献中已经报道了由于 CoP 误差导致峰值力矩发生变化。然而，对于可接受的误差水平存在争议。本研究旨在检查 CoP 误差对典型发育（TD）和脑瘫（CP）儿童步态中动力学特征的影响。记录了三维运动学和动力学数据，并在正后向和负后向以及内外侧方向上以 3mm、6mm、9mm、12mm 的增量应用模拟 CoP 误差。结合步态偏差指数-动力学（GDI-Kinetic）的变化，评估增量之间最大动力学参数的绝对差异。GDI-Kinetic 的变化超过 3.6 分被认为具有临床意义。在膝关节处，CP 高达 24.8%（CP）和 34.7%（TD）（矢状面）和高达 36.8%（CP）和 61.5%（TD）（冠状面）的最大峰值变化，而在一些误差增量处，绝对百分比差异较高，但 GDI-Kinetic 结果表明，如此大的百分比差异可能仍然具有临床意义。TD 儿童的 CoP 位移为 9mm 和 12mm 时，GDI-Kinetic 发生具有临床意义的变化，对应的最大力矩绝对值差异分别为 23%和 35%。相比之下，CP 儿童未达到具有临床意义的阈值，这可能与较慢的步行速度有关。本研究的结果强调了实验室需要考虑当前用于 CoP 误差的阈值，这将有助于指导质量保证程序。
