Background

Prostheses can help persons with trans-femoral amputation (TFA) regain normal function, but such individuals still exhibit gait deviations expressed in gait asymmetries. We apply a specialised tool, the Symmetry Function (SF), to evaluate the symmetry of walking in terms of kinematic and dynamic variables and to identify areas with large side deviations (exceeding defined ±5% threshold) in the movement cycle.

Research question

Which movements and joints or GRF components revealed the most significant side deviations in the movement cycle? When exactly are they located in the gate cycle?

Methods

In this retrospective observational study, an instrumented motion analysis system was used to register the gait of fourteen patients after unilateral TFA. Measurements involved evaluating the time series of gait variables characterising a range of motion and the ground reaction force components. Comparison of the prosthetic (involved) limb with the sound (uninvolved) limb in TFA patients was carried out on the basis of the Symmetry Function values.

Results

The Symmetry Function proved to be an effective tool to localise the regions of asymmetry and limb dominance in the full gait cycle. The difference between sides revealed by the Symmetry Function was the highest for the pelvis and the hip. In the sagittal plane, the pelvis was asymmetrically tilted, reaching the highest SF value of more than 25 % at 60 % cycle time. In the transverse plane, the pelvis was even more asymmetrically positioned throughout the entire gait cycle (50 % difference). The hip in the frontal plane reached a 60 % difference throughout the single support phase for the involved and then for the uninvolved limb.

Significance

The Symmetry Function allows for the detection of gait asymmetries, temporal shifts in the gait phases and may assess the precise in time adaptation of prostheses and rehabilitation monitoring, especially in unilateral impairments.

中文翻译：

---

对称性功能——评估经股截肢者步态对称性的有效工具

背景

假肢可以帮助跨股截肢 (TFA) 的人恢复正常功能，但这些人仍然表现出步态不对称的步态偏差。我们应用了一种专门的工具，对称函数 (SF)，根据运动学和动态变量评估步行的对称性，并识别运动周期中具有大侧偏差（超过定义的 ±5% 阈值）的区域。

研究问题

哪些运动和关节或 GRF 组件揭示了运动周期中最显着的侧向偏差？它们究竟何时位于门循环中？

方法

在这项回顾性观察研究中，使用仪器化运动分析系统记录单侧 TFA 后 14 名患者的步态。测量涉及评估表征运动范围和地面反作用力分量的步态变量的时间序列。基于对称函数值对 TFA 患者的假肢（受累）肢体与健全（未受累）肢体进行比较。

结果

对称函数被证明是在整个步态周期中定位不对称和肢体优势区域的有效工具。对称函数显示的两侧差异在骨盆和臀部最高。在矢状面，骨盆不对称倾斜，在 60% 的循环时间达到超过 25% 的最高 SF 值。在横向平面中，骨盆在整个步态周期中的位置更加不对称（差异为 50%）。在整个单次支撑阶段，受累肢体和随后未受累肢体的髋关节额平面达到了 60% 的差异。

意义

对称功能允许检测步态不对称、步态阶段的时间变化，并可以评估假肢和康复监测的精确时间适应，尤其是在单侧损伤中。