Transfemoral amputation is a serious intervention that alters the locomotion pattern, leading to secondary disorders and reduced quality of life. The outcomes of current gait rehabilitation for TFAs seem to be highly dependent on factors such as the duration and intensity of the treatment and the age or etiology of the patient. Although the use of robotic assistance for prosthetic gait rehabilitation has been limited, robotic technologies have demonstrated positive rehabilitative effects for other mobility disorders and may thus offer a promising solution for the restoration of healthy gait in TFAs. This study therefore explored the feasibility of using a bilateral powered hip orthosis (APO) to train the gait of community-ambulating TFAs and the effects on their walking abilities. Seven participants (46–71 years old with different mobility levels) were included in the study and assigned to one of two groups (namely Symmetry and Speed groups) according to their prosthesis type, mobility level, and prior experience with the exoskeleton. Each participant engaged in a maximum of 12 sessions, divided into one Enrollment session, one Tuning session, two Assessment sessions (conducted before and after the training program), and eight Training sessions, each consisting of 20 minutes of robotically assisted overground walking combined with additional tasks. The two groups were assisted by different torque-phase profiles, aiming at improving symmetry for the Symmetry group and at maximizing the net power transferred by the APO for the Speed group. During the Assessment sessions, participants performed two 6-min walking tests (6mWTs), one with (Exo) and one without (NoExo) the exoskeleton, at either maximal (Symmetry group) or self-selected (Speed group) speed. Spatio-temporal gait parameters were recorded by commercial measurement equipment as well as by the APO sensors, and metabolic efficiency was estimated via the Cost of Transport (CoT). Additionally, kinetic and kinematic data were recorded before and after treatment in the NoExo condition. The one-month training protocol was found to be a feasible strategy to train TFAs, as all participants smoothly completed the clinical protocol with no relevant mechanical failures of the APO. The walking performance of participants improved after the training. During the 6mWT in NoExo, participants in the Symmetry and Speed groups respectively walked 17.4% and 11.7% farther and increased walking speed by 13.7% and 17.9%, with improved temporal and spatial symmetry for the former group and decreased energetic expenditure for the latter. Gait analysis showed that ankle power, step width, and hip kinematics were modified towards healthy reference levels in both groups. In the Exo condition metabolic efficiency was reduced by 3% for the Symmetry group and more than 20% for the Speed group. This study presents the first pilot study to apply a wearable robotic orthosis (APO) to assist TFAs in an overground gait rehabilitation program. The proposed APO-assisted training program was demonstrated as a feasible strategy to train TFAs in a rehabilitation setting. Subjects improved their walking abilities, although further studies are required to evaluate the effectiveness of the APO compared to other gait interventions. Future protocols will include a lighter version of the APO along with optimized assistive strategies.

中文翻译：

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机器人介导的地面步态训练，用于双侧髋关节矫形器的大腿截肢者：一项初步研究

经股截肢是一种严重的干预措施，可改变运动模式，导致继发性疾病和生活质量下降。目前 TFA 步态康复的结果似乎高度依赖于诸如治疗的持续时间和强度以及患者的年龄或病因等因素。尽管机器人辅助在假肢步态康复中的使用受到限制，但机器人技术已证明对其他运动障碍有积极的康复作用，因此可能为 TFA 中健康步态的恢复提供有希望的解决方案。因此，本研究探讨了使用双侧动力髋关节矫形器 (APO) 来训练社区步行 TFA 的步态及其对步行能力的影响的可行性。七名参与者（46-71 岁，不同活动水平）被纳入研究，并根据他们的假肢类型、活动水平和外骨骼的先前经验被分配到两组（即对称组和速度组）中的一组。每位参与者最多参加 12 节课，分为 1 节报名课、1 节微课、2 节评估课（在训练计划之前和之后进行）和 8 节训练课，每节包括 20 分钟的机器人辅助地上行走结合额外的任务。这两个组由不同的扭矩相位曲线辅助，旨在提高对称组的对称性，并最大化速度组的 APO 传输的净功率。在评估会议期间，参与者进行了两次 6 分钟步行测试 (6mWTs)，一个有 (Exo) 一个没有 (NoExo) 外骨骼，以最大（对称组）或自选（速度组）速度。时空步态参数由商业测量设备和 APO 传感器记录，代谢效率通过运输成本 (CoT) 估算。此外，在 NoExo 条件下治疗前后记录动力学和运动学数据。一个月的培训方案被认为是培训 TFA 的可行策略，因为所有参与者顺利完成了临床方案，没有相关的 APO 机械故障。参加者的步行能力在训练后有所改善。在NoExo的6mWT中，对称组和速度组的参与者分别走得更远了17.4%和11.7%，步行速度分别提高了13.7%和17.9%，前者的时间和空间对称性得到改善，后者的能量消耗减少。步态分析表明，两组的踝关节力量、步宽和髋关节运动学都朝着健康的参考水平进行了修正。在 Exo 条件下，Symmetry 组的代谢效率降低了 3%，Speed 组的代谢效率降低了 20% 以上。本研究展示了第一个应用可穿戴机器人矫形器 (APO) 来协助 TFA 进行地上步态康复计划的试点研究。提议的 APO 辅助培训计划被证明是在康复环境中培训 TFA 的可行策略。受试者提高了他们的步行能力，但需要进一步研究来评估 APO 与其他步态干预相比的有效性。