Background

The goal of valgus knee brace treatment is to reduce medial knee joint loading during walking, often indicated by external knee adduction moment (KAM) measures. However, existing healthy-subjects studies have been equivocal in demonstrating KAM reduction with valgus knee bracing.

Research question

What are the immediate effects of valgus bracing at different tension levels on KAM during walking at a controlled speed and does body height modify the brace-KAM associations?

Methods

Data from 32 knee-healthy participants were analysed in this randomized crossover trial. Participants performed walking trials at controlled speed (1.3 ± 0.065 m/s) both with and without an Ossür Unloader One® brace. During the bracing condition, valgus tension was incrementally increased, from zero tension to normal tension and to maximum tolerable tension.

Results

Valgus bracing minimally increased knee flexion at heel-strike (P < 0.001) in a dose-dependent manner and minimally reduced gait velocity (∼0.015m/s) across all tension levels. Valgus bracing, overall, did not significantly reduce the various KAM measures. However, brace use at maximal tension was associated with a 0.04Nm/kg (9.2 %) increase in first peak KAM amongst participants with a body height of 1.75 m and a 0.03Nm/kg (7.6 %) decrease in first peak KAM amongst participants with a body height of 1.55 m.

Significance

Valgus bracing did not reduce the various KAM measures during walking; however, body height may play a moderating role. Given knee brace sizes vary more in circumference than length, this result may be due to the ratio between effective moment arm length relative to limb length. A deeper understanding of the potential neuro-biomechanical effects of valgus knee bracing and how these effects are potentially modified by body height may be critical to the design of effective knee braces.

中文翻译：

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外伤支撑对膝关节健康个体行走过程中膝关节瞬间的直接影响：身高的潜在调节作用。

背景

外翻护膝治疗的目的是减少步行过程中内侧膝关节的负荷，通常通过外部膝关节内收力矩（KAM）措施表明。但是，现有的健康受试者研究在通过外翻膝关节支撑降低KAM方面尚不明确。

研究问题

在以可控的速度行走时，不同张力水平的外翻支撑对KAM有哪些直接影响，而身高会改变支撑KAM的关联吗？

方法

在这项随机交叉试验中，分析了来自32位膝盖健康参与者的数据。参与者在有和没有OssürUnloaderOne®支撑的情况下均以受控速度（1.3±0.065 m / s）进行了步行试验。在支撑状态下，外翻张力逐渐增加，从零张力增加到正常张力，再到最大可承受的张力。

结果

外翻支撑以剂量依赖的方式最小程度地增加了脚跟打击时膝盖的屈曲（P <0.001），并且在所有张力水平上均最小地降低了步态速度（〜0.015m / s）。总体而言，外翻支具并未显着减少各种KAM措施。但是，在最大拉力下使用支具会使身高为1.75 m的参与者的第一峰值KAM增加0.04Nm / kg（9.2％），并使参与者的第一峰值KAM减少0.03Nm / kg（7.6％）车身高度为1.55 m。

意义

外翻支撑并没有减少步行过程中的各种KAM措施。但是，身高可能起调节作用。给定护膝尺寸在圆周上的变化大于长度的变化，此结果可能是由于有效力矩臂长度与肢体长度之比所致。更深入地了解外翻护膝的潜在神经生物力学作用以及如何通过身高潜在地改变这些作用对于有效护膝的设计至关重要。