Background

Prosthetic feet are available in a range of stiffness categories, however, there is limited evidence to guide optimal selection during prosthetic foot prescription. The aim of this study was to determine the effect of commercial prosthetic foot stiffness category on foot-ankle biomechanics, gait symmetry, community ambulation, and relative foot stiffness perception.

Methods

Participants were fit in randomized order with three consecutive stiffness categories of a commonly-prescribed prosthetic foot. Prosthetic foot roll-over shape and ankle push-off power and work were determined via data collected during walking in a motion analysis laboratory. Step activity was recorded during community use of each foot. Self-reported perception of relative foot stiffness was assessed with an ad hoc survey.

Findings

Seventeen males with transtibial amputation completed the study. Prosthetic foot roll-over radius increased with increased prosthetic foot stiffness categories (p < 0.001). Both prosthetic ankle push-off peak power and work decreased with increased foot stiffness categories (p = 0.002). There was no association between prosthetic foot stiffness category and step length symmetry or steps per day. When assessed post-accommodation, there was no association between relative foot stiffness perception and the stiffness category across prosthetic foot conditions.

Interpretation

Prosthetic foot stiffness category was significantly associated with changes in prosthetic foot-ankle biomechanical variables, however, was not associated with changes in gait symmetry or community ambulation. Relative prosthetic foot stiffness perception after accommodation was generally inconsistent with the order of prosthetic foot stiffness categories.

Clinical relevance

While there were quantifiable differences in prosthetic foot-ankle biomechanics across stiffness categories, no significant differences were detected in gait symmetry or mean daily step count in the community. Furthermore, after community use, participants perceptions of relative stiffness across feet were generally inconsistent with the order of prosthetic foot stiffness categories. These findings raise questions as to whether changes in commercial prosthetic foot stiffness category (within a clinically relevant range) affect subjective and objective measures relevant to successful outcomes from prosthetic foot prescription.

中文翻译：

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假肢脚刚度对胫骨截肢患者脚踝生物力学和相对脚刚度知觉的影响。

背景

假脚可在一系列的硬度类别中使用，但是，在假脚处方期间，指导使用最佳选择的证据有限。这项研究的目的是确定商业假肢足部僵硬度类别对足踝生物力学，步态对称性，社区下肢活动和相对足部僵硬感的影响。

方法

参与者以随机顺序与常见处方假脚的三个连续刚度类别进行匹配。通过在运动分析实验室中行走过程中收集的数据来确定假肢的足部翻滚形状，踝关节下垂的力量和工作量。在社区使用每只脚期间记录了脚步活动。通过特设调查评估自我报告的相对足部僵硬感。

发现

十七名经胫骨截肢的男性完成了研究。假脚的翻倒半径随假脚硬度类别的增加而增加（p  <0.001）。假肢脚踝下垂的峰值功率和功均随着脚部刚度类别的增加而降低（p  = 0.002）。假足硬度类别与步长对称性或每天步数之间没有关联。在住宿后进行评估时，相对足部僵硬感和跨足假肢状况的僵硬类别之间没有关联。

解释

假肢的脚部僵硬类别与假肢的脚踝生物力学变量的变化显着相关，但是与步态对称性或社区活动性的变化无关。适应后相对假肢足部刚度的感觉通常与假肢足部刚度类别的顺序不一致。

临床相关性

虽然跨僵硬类别的假肢脚踝生物力学存在可量化的差异，但在社区中步态对称性或平均每日步数没有发现显着差异。此外，在社区使用后，参与者对双脚相对僵硬的认识通常与假肢脚僵硬类别的顺序不一致。这些发现提出了以下疑问：商业义肢脚硬度类别的变化（在临床相关范围内）是否会影响与假脚处方成功结果相关的主观和客观指标。