Jackie and Gene Autry Orthopaedic Center, Children's Hospital Los Angeles, Los Angeles, USA; Departments of Orthopaedic Surgery, Radiology, and Biomedical Engineering, University of Southern California, Los Angeles, USA.
Jackie and Gene Autry Orthopaedic Center, Children's Hospital Los Angeles, Los Angeles, USA.
Gait Posture. 2023 Jul;104:9-14. doi: 10.1016/j.gaitpost.2023.05.029. Epub 2023 Jun 1.
Markerless motion capture systems have the potential to make clinical gait analysis more efficient and convenient. Theia3D is a commercially available markerless system that may serve as an alternative to traditional gait analysis for clinical gait laboratories.
What is the concurrent validity of markerless gait analysis using Theia3D compared to traditional marker-based gait analysis in pediatric clinical gait patients?
Thirty-six patients (20 male, age 2-25 years) with a range of diagnoses underwent clinical gait analysis with data being captured concurrently by a traditional marker-based motion capture system (Vicon Nexus) and a commercial markerless system (Theia3D). Multiple left strides were averaged for each subject, and the difference in kinematics (Theia - Vicon) was calculated over the gait cycle and evaluated using root mean square difference (RMSD), mean difference, and RMSD after subtracting the mean value across the gait cycle (RMSD). Sub-analysis was performed for 25 patients with foot deformities, 9 wearing ankle-foot orthoses, and 6 walking with assistance (cane, crutches, walker, or handheld).
Kinematics showed similar patterns between the marker-based and markerless systems. RMSD was < 6° except for pelvic tilt, hip flexion, ankle inversion, foot progression, and transverse plane rotation of the hip, knee, and ankle. These measures mainly differed due to an offset between the curves. After adjusting for offsets, all RMSD were < 6°. RMSD was larger for patients with foot deformities, wearing orthoses, or using assistive devices, but all RMSD were still < 8°. In some cases, however, the markerless system had greater trial-to-trial variability, showed a larger knee varus "bump" in swing, or failed to track the subject.
This study provides preliminary evidence of concurrent validity of Theia3D for pediatric patients with abnormal gait. However, some questions remain regarding identification of the knee axis and for patients with foot deformity or assistive devices.
无标记运动捕捉系统有可能使临床步态分析更加高效和便捷。Theia3D 是一种商用的无标记系统，它可能成为临床步态实验室传统步态分析的替代方法。
与传统基于标记的步态分析相比，使用 Theia3D 进行无标记步态分析在儿科临床步态患者中的同时效度如何？
36 名患者（20 名男性，年龄 2-25 岁）接受了临床步态分析，数据由传统基于标记的运动捕捉系统（Vicon Nexus）和商用无标记系统（Theia3D）同时采集。每位患者平均采集多个左步，计算步态周期内运动学的差异（Theia-Vicon），并使用均方根差（RMSD）、平均值差异和减去步态周期平均值后的 RMSD（RMSD）进行评估。对 25 名足部畸形患者、9 名佩戴踝足矫形器的患者和 6 名使用辅助工具（拐杖、助行器、步行器或手持式）的患者进行了亚分析。
运动学在基于标记和无标记系统之间显示出相似的模式。除了骨盆倾斜、髋关节屈曲、踝关节内翻、足前进和髋关节、膝关节和踝关节的横平面旋转外，RMSD 均<6°。这些测量主要是由于曲线之间的偏移。在调整了偏移量后，所有 RMSD 均<6°。足部畸形、佩戴矫形器或使用辅助工具的患者 RMSD 较大，但所有 RMSD 仍<8°。然而，在某些情况下，无标记系统的试验间变异性更大，摆动时出现更大的膝内翻“凸起”，或者无法跟踪受试者。
本研究初步证明了 Theia3D 在患有异常步态的儿科患者中的同时效度。然而，对于膝关节轴的识别以及足部畸形或辅助设备的患者，仍存在一些问题。
