足三维运动的热塑标志测量法

背景：足关节运动变化的动力学研究被广泛应用于临床步态分析、工业机器人和制鞋等领域。应用于二维测量技术已经不能准确地反映足的功能变化和标记的三维运动状况。目的：了解足在三维空间中的角度变化规律。设计：实验研究。地点和对象：在德国Erlangen-Nuremberg大学骨科医院三维运动分析实验室完成，选择5例正常人作足三维运动分析，男3例，女2例；年龄30～50岁。方法：应用热塑材料作三维标志的支架．紧贴足背、足跟。通过ALBAV-ISION ACAM50三维运动分析系统定位标志在三维坐标系的位置，计算出足在三维空间中的角度。主要观察指标：足在三维空间的角度及角度曲线。结果：正确描绘了足的三维运动规律。反映了足的内外旋，内外翻，前后转的过程。结论：该测量方法是一个较为完善的三维人体运动临床和科研分析方法：     

三维运动解析系统测试脑卒中偏瘫步态的运动学定量评价

背景:近年来兴起的三维运动解析技术,可获得多项行走过程中的生物力学参数,代表了目前步态生物力学研究的先进水平.目前该技术在国外开展较多,而国内则较少.国内有限的研究主要集中在对偏瘫患侧下肢矢状面上运动的分析.目的:对偏瘫患者步行运动进行三维立体运动学分析,与正常步态对比,分析脑卒中偏瘫步态的运动学变化特征.方法:运用三维运动解析系统,对10例首发缺血性脑卒中偏瘫患者进行步态分析,以10例健康者作为对照.检测健康对照组步行过程中的基本时空参数、步态周期参数与骨盆三维运动角度参数,并对其运动过程中的对称性进行分析.检测两组下肢髋、膝、踝关节的三维运动学角度参数,对比两组下肢关节运动在矢状面、横断面与冠状面上的变化特征.结果与结论:偏瘫步态表现出下肢运动膝关节屈曲受限,膝关节活动度减小.髋关节内收、旋内不足,外展与旋外角度增大.提示三维运动解析系统测试可测定偏瘫患者步行功能,定量评价偏瘫患者下肢关节运动变化,从而进行相应针对性的稳定性与协调性训练.     

实时三维超声成像在诊断胎儿体表畸形中的应用价值

目的评价实时三维超声在诊断胎儿体表畸形中的价值。方法采用表面成像及透明成像法对50例常规产前二维超声检查疑为胎儿体表畸形的患者行实时三维超声成像,并与引产后病理尸解结果对照,比较二维与三维超声检查与病理诊断符合率。结果50例中检出12种体表畸形,其中头颈及颜面部畸形28例,包括无脑儿4例,颈部淋巴囊肿4例,脑膜膨出3例,唇裂15例,耳畸形2例;内脏及躯干畸形9例,包括脐膨出4例,开放性脊柱裂5例;四肢畸形13例,包括四肢短小畸形5例,足内翻5例,前臂畸形1例,手畸形1例,重叠指1例。50例中48例成功获得病变部位三维立体图像,漏诊耳畸形2例。产前二维及三维超声对胎儿体表畸形判断准确率分别为70．0％（35／50）和96．0％（48／50）。结论实时三维超声成像可获得胎儿体表畸形立体图像,还可显示胎儿运动,是二维超声的重要补充,且在胎儿畸形检出率和准确性上均优于二维超声。     

脑动脉瘤虚拟三维模型的建立及其应用价值初探

目的建立脑动脉瘤的虚拟三维模型并探讨其临床应用价值.方法分别对20例正常脑血管和216例脑动脉瘤的DSA资料进行分析整理,选取具有代表性的DSA资料作为蓝本,利用三维制作软件3D Studio MAX R3创建虚拟的脑动脉系统和动脉瘤模型,并由多名医生评价该模型与DSA图像的相似性,最后考察虚拟模型在临床教学和造影诊断工作中的应用价值.结果①虚拟脑动脉系统与DSA图像相比,在形态上具有相似性,在视觉上更容易理解血管的三维空间关系;②虚拟动脉瘤与DSA图像相比,能正确表现动脉瘤的发生部位、生长方向和形态特点;③在临床教学上能帮助学习者建立并加强血管和动脉瘤的三维空间概念;④通过模拟瘤体和瘤颈的最佳的显示角度,指导血管造影工作角度的选择.结论由软件方法建立的脑动脉瘤虚拟三维模型对于形态学研究和指导临床工作具有重要作用.     

实时三维超声心动图引导室间隔缺损介入封堵术的初步研究

室间隔缺损（VSD）是最常见的先天性心脏病，约占先天性心脏病的20％～30％。近年来对VSD封堵治疗成为一个热点，以往在介入术中均不能完全脱离放射线指导。新近应用于临床的实时三维超声心动图（RT-3DE）能从三维空间角度实时立体显示心脏结构，从而提供较二维超声心动图更多的信息，本研究探讨应用RT-3DE诊断和引导VSD封堵的可行性。     

三维运动分析系统在健康人平衡功能质心检测中三种方法一致性的比较

目的:探讨采用三维运动分析系统检测健康人质心的骶骨标记法、测力台法和节段法的一致性,为骶骨标记法用于临床平衡功能评价提供依据。方法:20例健康中年人自愿参加本研究,分别在双腿站、左腿站和右腿站的体位接受三维运动分析系统中的骶骨标记点(SM)的三维空间数据、测力台压力中心(COP)的数据采集和节段法21个标记点的三维空间数据采集以计算获得质心(COM)位置。使用Bland-Altman法比较SM、COP和COM在不同方向上的一致性,及其平均摆动幅度(MSA)的一致性;使用单因素方差分析比较不同站立姿势上述参数之间的差异;并绘出COM和COP、SM的空间位置关系图。结果:SM与COM在左右方向上一致性较好,COP和COM在前后、左右方向上一致性都好;SM、COP的MSA和COM的MSA比较在各方向上的一致性均良好;站立位时COM位于SM下方16mm、前方154mm、左侧9.3mm处;不同站立位下SM、COP和COM的MSA均有显著性差异。结论:以三维运动分析系统检测人体平衡功能质心时,采用骶骨标记法和测力台法相关参数与节段法相比一致性良好,而且可以反映不同体位下质心变化时MSA的变化,可用于站立位平衡功能的检测。     

实时三维超声心动图斑点追踪技术评价正常人左心室心肌应变

目的 评价三维超声斑点追踪技术测量正常人左室心肌应变的能力,并对心肌总应变矢量的大小和角度进行初步研究.方法 使用三维超声斑点追踪和二维超声斑点追踪技术对31例健康志愿者进行了心肌运动分析,测量左室的纵向、圆周向及径向应变,并通过纵向及圆周向应变计算心肌总应变矢量的大小及角度.结果 三维斑点追踪测得的纵向及圆周向应变在左室整体及各短轴水平均小于二维应变,而径向应变则相反.三维斑点追踪测得的心肌应变在左室不同水平间存在差异,左室中部水平的纵向、圆周向及径向应变均大于基底部及心尖部水平,而二维应变在不同水平间的差异未显示出明显规律.通过测量的纵向及圆周向应变计算得到心肌总应变矢量大小和角度,应用三维应变计算出的心肌总应变矢量绝对值在左室中部水平最大,而总应变矢量角度在不同水平间无明显差异.结论 三维斑点追踪可通过测量心肌应变对左室局部功能进行准确评价且重复性良好,具有潜在的临床应用价值.     

三维斑点追踪技术在肥厚型心肌病心功能评价中的应用

超声心动图检查是临床评估患者心功能常用手段之一。心功能的有效评价直接影响患者临床治疗的进行和选择,早期、客观、有效的评价患者心功能对其治疗与预后十分重要。三维斑点追踪技术(3D speckle tracking imaging,3D-STI)作为一种全新的技术在心功能的评价中摒弃了传统组织多普勒角度依赖的限制,克服了二维斑点追踪显像(2D speckle tracking imaging,2D-STI)局限于二维平面的弊端,从全新的角度对心脏各种运动形式进行定量分析。本文从3D-STI在正常成人左室心肌三维应变中的初步研究,论述了其在心功能评价中的可行性。并对3D-STI在肥厚型心肌病左心室功能评价中的研究进行综述。     

实时三维（四维）超声在产科中的应用价值

目的:探讨实时三维(四维)彩色多普勒超声在胎儿成像中的应用价值。方法:应用GE公司Volnson730对89例妊娠中晚期胎儿做二维及实时三维(四维)彩色多普勒超声检查,重点对胎儿面部、手、足等解剖结构感兴趣区进行扫查,应用实时三维(四维)超声对胎儿运动情况进行观察。结果:实时三维(四维)能够清晰显示胎儿表面解剖结构,对胎儿在母体内的运动立体图像进行实时观察,不但增进了孕妇及家人对胎儿的认识率,而且对胎儿畸形筛查有很大的帮助。结论:实时三维(即四维)超声不仅是对胎儿在母体内的立体图像的实时观察,使孕妇及家属对胎儿产前即有了解,更是提高胎儿畸形诊断率的最有效手段。     

实时动态三维超声在胎儿成像中的应用

目的探讨实时动态三维超声在胎儿成像中的应用价值.方法对64例妊娠中晚期胎儿表面轮廓、四肢等表面结构进行二维及动态三维超声检查及观察胎儿在母体内的运动.结果实时动态三维超声所获取的胎儿图像立体感强、层次分明、清晰易辨认,并且实现了对胎儿运动立体图像的实时观察.结论实时动态三维超声能更为详细全面地提供胎儿形态信息及运动状况,是无创性产前诊断技术的研究发展方向之一.     

RELIABILITY OF VIDEO‐BASED QUANTIFICATION OF THE KNEE‐ AND HIP ANGLE AT FOOT STRIKE DURING RUNNING

Introduction:

In clinical practice, joint kinematics during running are primarily quantified by two‐dimensional (2D) video recordings and motion‐analysis software. The applicability of this approach depends on the clinicians’ ability to quantify kinematics in a reliable manner. The reliability of quantifying knee‐ and hip angles at foot strike is uninvestigated.

Objective:

To investigate the intra‐ and inter‐rater reliability within and between days of clinicians’ ability to quantify the knee‐ and hip angles at foot strike during running.

Methods:

Eighteen recreational runners were recorded twice using a clinical 2D video setup during treadmill running. Two blinded raters quantified joint angles on each video twice with freeware motion analysis software (Kinovea 0.8.15)

Results:

The range from the lower prediction limit to the upper prediction limit of the 95% prediction interval varied three to eight degrees (within day) and nine to 14 degrees (between day) for the knee angles. Similarly, the hip angles varied three to seven degrees (within day) and nine to 11 degrees (between day).

Conclusion:

The intra‐ and inter rater reliability of within and between day quantifications of the knee‐ and hip angle based on a clinical 2D video setup is sufficient to encourage clinicians to keep using 2D motion analysis techniques in clinical practice to quantify the knee‐ and hip angles in healthy runners. However, the interpretation should include critical evaluation of the physical set‐up of the 2D motion analysis system prior to the recordings and conclusions should take measurement variations (3‐8 degrees and 9‐14 degrees for within and between day, respectively) into account.

Level of evidence:

3     

Dual-channel cascade pose estimation network trained on infrared thermal image and groundtruth annotation for real-time gait measurement

Real-time spatiotemporal parameter measurement for gait analysis is challenging. Previous techniques for 3D motion analysis, such as inertial measurement units, marker based motion analysis or the use of depth cameras, require expensive equipment, highly skilled staff and limits feasibility for sustainable applications. In this paper a dual-channel cascaded network to perform contactless real-time 3D human pose estimation using a single infrared thermal video as an input is proposed. An algorithm to calculate gait spatiotemporal parameters is presented by tracking estimated joint locations. Additionally, a training dataset composed of infrared thermal images and groundtruth annotations has been developed. The annotation represents a set of 3D joint locations from infrared optical trackers, which is considered to be the gold standard in clinical applications. On the proposed dataset, our pose estimation framework achieved a 3D human pose mean error of below 21 mm and outperforms state-of-the-art methods. The results reveal that the proposed system achieves competitive skeleton tracking performance on par with the other motion capture devices and exhibited good agreement with a marker-based three-dimensional motion analysis system (3DMA) over a range of spatiotemporal parameters. Moreover, the process is shown to distinguish differences in over-ground gait parameters of older adults with and without Hemiplegia’s disease. We believe that the proposed approaches can measure selected spatiotemporal gait parameters and could be effectively used in clinical or home settings.     

Validation of a 3D optoelectronic motion analysis system for the wrist joint

Objective. A study was undertaken to determine the experimental accuracy of a non-invasive optoelectonic 3-dimensional tracking system in assessing wrist joint motion.

Design. This was an in vivo experimental study involving volunteer subjects performing prescribed wrist motions.

Background. Current clinical practice does not include routine kinematic analysis for evaluating arthritic disease state, although motion disorders are common.

Methods. Surface markers were applied to 24 subjects assigned two hand postures in a test-retest factorial design for the expected range of motion. The marker positions were measured optoelectronically and using calibrated stereoradiography, to determine the positions of the surface markers and of key bone landmarks. Alignment and motion were compared for the three measurement techniques. Standard kinematic analyses were performed to extract Euler angles and equivalent screw displacement axes for paired postures.

Results. The three measurement techniques were highly correlated for wrist flexion-extension. Uncertainties were less than 6 degrees, similar to uncertainties from bone landmark identification errors when implanted markers cannot be used. Measures of motion exhibited higher correlations than those for alignment. Equivalent screw displacement axis orientations had poor intraclass correlations, reflecting sensitivity to coordinate system definitions.

Conclusions. For motion analysis in the wrist in vivo, a non-invasive optoelectronic measurement system is as accurate as stereoradiographic analysis of bone segments.     

A new protocol for 3D assessment of foot during gait: Application on patients with equinovarus foot

Background

The aim of this study is to assess the clinical value of a recently introduced original protocol for full three dimensional analysis of ankle rotations in patients with equinovarus foot.

Methods

A preliminary study merging the Total3Dgait protocol and the conventional Vicon® Plug-in-Gait marker-sets on five patients with foot deformity was performed to compare the output exactly over the same gait cycles. In the second study, 15 patients with equinus varus foot were assessed retrospectively by means of the Total3Dgait protocol before and after surgery. Data on ankle kinematics were compared to those of a control group. The Functional Ambulation Categories scale and other goals such as orthosis/aids removal, decrease in foot pain, healing of calluses and sores were considered as measures of clinical outcome.

Findings

The Total3Dgait protocol provides additional joint motion, in the coronal and transverse planes. Kinematics in the three anatomical planes improved significantly although no changes in time-distance parameters were evident. Improvement in clinical outcome measures was also achieved.

Interpretation

The new protocol provides valuable additional data in measuring full three dimensional kinematics of the foot during gait. Whereas the speed of walking was unchanged after surgery for most of patients, the kinematic changes in the three anatomical planes, as measured by the new protocol, were the only measures able to demonstrate motion changes induced by surgery at the foot and to explain subject-specific gains as improvement in stability during walking, relief of pain, calluses and sores, and removal or modification of foot orthosis and aids.     

Accuracy of digitization using automated and manual methods.

BACKGROUND AND PURPOSE: Computerized 3-dimensional (3-D) motion measurement systems are used by those interested in human motion. The purposes of this study were (1) to determine the limits of accuracy in determining intersegmental angles during pendular motion at varying speeds and (2) to determine changes in accuracy introduced by autodigitization and digitization by experienced manual raters. METHODS: Angular speed of a T-shaped pendulum was systematically increased by releasing the pendulum from 4 angles (0 degrees [no movement], 45 degrees, 90 degrees, and 120 degrees). Twelve reference angles calculated from markers placed on the pendulum were estimated over 20 frames for 10 trials at each release position. RESULTS: Mean errors across trials and frames for intersegmental angles reconstructed by a 3-D motion measurement system were within +/- 1 degree across all release positions. An analysis of variance and a post hoc Tukey test revealed that the mean error for the autodigitized trials was larger than that for the manually digitized trials. For the autodigitized trials, the static trials (release position=0 degrees) produced less mean error than the trials with movement produced. The ICCs showed a high degree of consistency among all raters, ranging from .707 to .999. CONCLUSION AND DISCUSSION: Our findings support the conclusion that under carefully controlled conditions, a 3-D motion measurement system can produce clinically acceptable measurements of accuracy across a range of angular speeds. Furthermore, acceptable accuracy is possible regardless of the digitization method.     

Analysis of passive motion characteristics of the ankle joint complex using dual Euler angle parameters

OBJECTIVE: To apply the dual Euler angles method to investigate the passive motion characteristics of the human ankle joint complex. DESIGN: Three-dimensional kinematic data of the ankle joint complex was collected from 10 knee-below foot cadaver specimens. BACKGROUND: Besides the Euler angles and screw axis methods, the dual Euler angles method has been proposed as an alternative approach to quantify general spatial human joint motion. The dual Euler angles method provides a way to combine rotational and translational joint motions and to interpret motions in Cartesian coordinate systems, which can avoid the problems caused by the use of the joint coordinate system due to non-orthogonality. METHODS: A non-metal experimental setup was fabricated to generate motion in foot cadaver specimens. The kinematic data during passive dorsiflexion-plantarflexion was measured using an electromagnetic tracking device. RESULTS: The kinematic coupling characteristics and the respective contribution of the ankle joint and the subtalar joint to the gross motion of the foot with respect to the shank were analyzed based on dual Euler angle parameters. The results obtained in this study are generally in agreement with the observations reported previously. CONCLUSIONS: The dual Euler angles method is suitable for analyzing the motion characteristics of the ankle joint complex. The motion at the ankle joint complex involves rotations about and translations along three axes.     

Concurrent validity and reliability of two-dimensional video analysis of hip and knee joint motion during mechanical lifting

Movement patterns used during mechanical lifting are usually assessed subjectively by clinicians as a stoop or squat based on visual estimation of joint motion and position. Two-dimensional (2D) video analysis has the potential to objectively measure joint motion during a mechanical lifting task. This study investigated concurrent validity, intrarater, interrater, and test-retest reliability of 2D video analysis using Dartfish software for the measurement of sagittal plane angles at the hip and knee during mechanical lifting. Fifteen healthy female participants (mean age 27.1?±?7.1 years) were recruited to perform mechanical lifting on 2 separate test days. Concurrent validity was determined by comparing 2D derived hip and knee flexion angles to goniometric measures. Intrarater and interrater reliability of the 2D kinematic procedures was determined by using examiners with varying experience in the use of Dartfish software. Between-day test-retest reliability of hip and knee 2D kinematics during mechanical lifting was assessed. Concurrent validity of 2D angle analysis using Dartfish software was supported by high correlations (Pearson r?≥?0.95) and nonsignificant differences between 2D and goniometric measures of sagittal plane hip and knee motion. Both intrarater and interrater reliability values of hip and knee flexion angles were excellent (ICC?≥?0.91). ICCs for test-retest reliability were 0.79 and 0.91 for hip and knee flexion, respectively. These findings and the ease of data capture using this system provide support for the clinical utility of 2D video analysis to provide objective measures of movement patterns at the hip and knee during a dynamic functional task.     

RELIABILITY AND ACCURACY OF A GONIOMETER MOBILE DEVICE APPLICATION FOR VIDEO MEASUREMENT OF THE FUNCTIONAL MOVEMENT SCREEN DEEP SQUAT TEST

Background/Purpose

The squat is a fundamental movement of many athletic and daily activities. Methods to clinically assess the squat maneuver range from simple observation to the use of sophisticated equipment. The purpose of this study was to examine the reliability of Coach''s Eye (TechSmith Corp), a 2‐dimensional (2D) motion analysis mobile device application (app), for assessing maximal sagittal plane hip, knee, and ankle motion during a functional movement screen deep squat, and to compare range of motion values generated by it to those from a Vicon (Vicon Motion Systems Ltd) 3‐dimensional (3D) motion analysis system.

Methods

Twenty‐six healthy subjects performed three functional movement screen deep squats recorded simultaneously by both the app (on an iPad [Apple Inc]) and the 3D motion analysis system. Joint angle data were calculated with Vicon Nexus software (Vicon Motion Systems Ltd). The app video was analyzed frame by frame to determine, and freeze on the screen, the deepest position of the squat. With a capacitive stylus reference lines were then drawn on the iPad screen to determine joint angles. Procedures were repeated with approximately 48 hours between sessions.

Results

Test‐retest intrarater reliability (ICC_3,1) for the app at the hip, knee, and ankle was 0.98, 0.98, and 0.79, respectively. Minimum detectable change was hip 6°, knee 6°, and ankle 7°. Hip joint angles measured with the 2D app exceeded measurements obtained with the 3D motion analysis system by approximately 40°. Differences at the knee and ankle were of lower magnitude, with mean differences of 5° and 3°, respectively. Bland‐Altman analysis demonstrated a systematic bias in the hip range‐of‐motion measurement. No such bias was demonstrated at the knee or ankle.

Conclusions

The 2D app demonstrated excellent reliability and appeared to be a responsive means to assess for clinical change, with minimum detectable change values ranging from 6° to 7°. These results also suggest that the 2D app may be used as an alternative to a sophisticated 3D motion analysis system for assessing sagittal plane knee and ankle motion; however, it does not appear to be a comparable alternative for assessing hip motion.

Level of Evidence

3     

Influence of marker models on ankle kinematics in persons with partial foot amputation: an investigation using a mechanical model

Previous studies have found that ankle dorsiflexion increases in persons with partial foot amputation walking shod or in "below-ankle" devices compared with walking barefoot. However, a logical biomechanical explanation for these findings has not been offered. The purpose of this project was to determine whether marker location might explain the exaggerated dorsiflexion reported in the literature and, if so, whether more accurate data could be obtained with a different marker set. An articulated mechanical model of the shank and partial foot residuum was constructed with a potentiometer located within the mechanical ankle joint. Ankle angles measured with the calibrated potentiometer were compared with those obtained with both the Helen Hayes marker set and an alternative "residual end" marker set. Results indicated that both marker sets provided accurate and comparable measures at the metatarsophalangeal and transmetatarsal levels. At the Lisfranc level, the Helen Hayes marker set overestimated the ankle angles, primarily because of deformation of the prosthetic forefoot. These results confirm that the choice of kinematic model does influence measurements of ankle motion in persons with partial foot amputation and that the residual end marker set more accurately measures ankle motion at the Lisfranc level.