Background

Minimum Toe Clearance (MTC) is defined as the minimum vertical distance between the lowest point under the front part of the foot and the ground, during mid-swing. Low values of MTC and walking on inclines are both related to higher probability of tripping and falling in lower limb amputees. New prosthetic designs aim at improving MTC, especially on ramps, however the real effect on MTC still needs investigation. The objective of this study was then to evaluate the effect of different prosthetic designs on MTC in inclined walking.

Methods

Thirteen transtibial amputees walked on a ramp using three different prostheses: non articulating ankle (NAA), articulating hydraulic ankle (AHA), and articulating hydraulic ankle with microprocessor (AHA-MP). Median MTC, coefficient of variation (CV), and tripping probability (TP) for obstacles of 10 and 15 mm were compared across ankle type in ascent and descent.

Findings

When using AHA-MP, larger MTC median values for ascending (P ≤ 0.001, W = 0.58) and descending the ramp (P = 0.003, W = 0.47) were found in the prosthetic limb. Also significantly lower CV was found on the prosthetic limb for both types of AHA feet when compared to NAA for descending the ramp (P = 0.014, W = 0.45). AHA-MP showed the lowest TP for the prosthetic leg in three conditions evaluated. On the sound limb results showed the median MTC was significantly larger (P = 0.009, W = 0.43) and CV significantly lower (P = 0.005, W = 0.41) when using an AHA in ascent.

Interpretation

Both AHA prosthetic designs help reduce the risk of tripping of the prosthetic limb by increasing the median MTC, lowering its variability and reducing TP for both legs when ascending and descending the ramp. For most of the conditions, AHA-MP showed the lowest TP values. Findings suggest that AHA prostheses, especially AHA-MP could reduce the risk of tripping on ramps in amputees.

中文翻译：

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在具有不同假体设计的坡道上行走的单侧胫骨截肢患者的最小脚趾间隙和绊倒可能性。

背景

最小脚趾间隙（MTC）定义为挥杆过程中脚前部下方最低点与地面之间的最小垂直距离。MTC值较低和在斜坡上行走都与下肢截肢者绊倒和跌倒的可能性较高有关。新的假体设计旨在改善MTC，尤其是在坡道上，但是对MTC的实际影响仍需调查。然后，本研究的目的是评估倾斜行走中不同假体设计对MTC的影响。

方法

十三位经截肢的截肢者使用三种不同的假体在坡道上行走：非关节踝（NAA），关节液压踝（AHA）和带有微处理器的关节液压踝（AHA-MP）。在上升和下降过程中，比较了踝部类型为10和15 mm的障碍物的中值MTC，变异系数（CV）和跳闸概率（TP）。

发现

当使用AHA-MP时，在假肢中发现较大的MTC中间值（上升（P≤0.001，W = 0.58）和下降斜坡（P = 0.003，W = 0.47））。与下降坡道的NAA相比，两种类型的AHA脚的假肢上的CV均显着降低（P = 0.014，W = 0.45）。在评估的三种情况下，AHA-MP显示出假肢的最低TP。在健全肢体上的结果显示，当使用AHA进行上升时，中位MTC显着更大（P = 0.009，W = 0.43），CV显着更低（P = 0.005，W = 0.41）。

解释

两种AHA假体设计均可以通过增加中位MTC，降低其可变性并降低上下坡道时两条腿的TP来降低假肢跳脱的风险。在大多数情况下，AHA-MP的TP值最低。研究结果表明，AHA假体，尤其是AHA-MP可以减少被截肢者在斜坡上绊倒的风险。