BACKGROUND Individuals with lower limb amputation commonly exhibit large gait asymmetries that are associated with secondary health issues. It has been shown that they are capable of attaining improved temporal and propulsive symmetry when walking with a powered knee prosthesis and visual feedback, but they perceive this pattern of gait to be more difficult. Rather than improving the efficiency of gait, improved gait symmetry may be increasing individuals' effort associated with maintaining lateral balance. METHODS In this study, we used a simple visual feedback paradigm to increase the prosthesis-side stance time of six individuals with unilateral TFA or KD as they walked on a powered knee prosthesis at their self-selected speed. As they walked more symmetrically, we evaluated changes in medial-lateral center-of-mass excursion, lateral margin of stability, stride width, and hip abductor activity. RESULTS As the subjects increased their prosthesis-side stance time, their center-of-mass excursion and hip abductor activity significantly increased, while their lateral margin of stability significantly decreased on the prosthesis-side only. Stride width remained relatively unchanged with testing condition. CONCLUSIONS Extended stance time on a powered knee prosthesis (yielding more symmetric gait) challenged the lateral balance of individuals with lower limb amputation. Lateral stability may be a reason they prefer an asymmetric gait, even with more advanced technology. Hip muscular changes post-amputation may contribute to the decline in stability on the prosthesis side. Interventions and advancements in prosthesis control aimed at improving their control of lateral balance may ameliorate the difficulty in walking with improved gait symmetry.

中文翻译：

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单侧截肢患者行走过程中延长站姿时间对动力膝关节假体的影响和步态对称对平衡侧向控制的影响。

背景技术具有下肢截肢的个体通常表现出步态不对称性大，其与继发性健康问题相关。已经表明，当用动力膝关节假体和视觉反馈行走时，它们能够获得改善的时间和推进对称性，但是他们认为这种步态更加困难。改善步态的对称性而不是提高步态的效率，而可能是增加与保持横向平衡有关的个人努力。方法在本研究中，我们使用简单的视觉反馈范例来增加六名单侧TFA或KD个体以自行选择的速度行走在动力膝关节假体上时的假体侧站立时间。当他们行走更加对称时，我们评估了内侧-外侧质心偏移的变化，稳定的侧缘，步幅宽度和髋外展肌活动。结果随着受试者增加假肢侧站立时间，他们的质心偏移和髋外展肌活动显着增加，而他们的侧向稳定裕度仅在假肢侧显着下降。步幅在测试条件下保持相对不变。结论电动膝关节假体的站立姿势时间延长（步态更加对称）挑战了下肢截肢患者的侧向平衡。即使使用更先进的技术，横向稳定性也可能是他们偏爱步态不对称的原因。截肢后髋部肌肉变化可能会导致假体一侧稳定性下降。