School of Sport Science, Exercise and Health, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA, 6009, Western Australia,
Clin Orthop Relat Res. 2014 Mar;472(3):915-22. doi: 10.1007/s11999-013-3297-8. Epub 2013 Sep 25.
Unloading knee braces often are used after tibiofemoral articular cartilage repair. However, the experimental basis for their use in patients with normal tibiofemoral alignment such as those undergoing cartilage repair is lacking.
QUESTIONS/PURPOSES: The purpose of this study was to investigate the effect of varus and valgus adjustments to one commercially available unloader knee brace on tibiofemoral joint loading and knee muscle activation in populations with normal knee alignment.
The gait of 20 healthy participants (mean age 28.3 years; body mass index 22.9 kg/m(2)) was analyzed with varus and valgus knee brace conditions and without a brace. Spatiotemporal variables were calculated as were knee adduction moments and muscle activation during stance. A directed cocontraction ratio was also calculated to investigate the relative change in the activation of muscles with medial (versus lateral) moment arms about the knee. Group differences were investigated using analysis of variance. The numbers available would have provided 85% power to detect a 0.05 increase or decrease in the knee adduction moment (Nm/kg*m) in the braced condition compared with the no brace condition.
With the numbers available, there were no differences between the braced and nonbraced conditions in kinetic or muscle activity parameters. Both varus (directed cocontraction ratio 0.29, SD 0.21, effect size 0.95, p = 0.315) and valgus (directed cocontraction ratio 0.28, SD 0.24, effect size 0.93, p = 0.315) bracing conditions increased the relative activation of muscles with lateral moment arms compared with no brace (directed cocontraction ratio 0.49, SD 0.21).
Results revealed inconsistencies in knee kinetics and muscle activation strategies after varus and valgus bracing conditions. Although in this pilot study the results were not statistically significant, the magnitudes of the observed effect sizes were moderate to large and represent suitable pilot data for future work. Varus bracing increased knee adduction moments as expected; however, they produced a more laterally directed muscular activation profile. Valgus bracing produced a more laterally directed muscular activation profile; however, it increased knee adduction moments.
When evaluating changes in knee kinetics and muscle activation together, this study demonstrated conflicting outcomes and questions the efficacy for the use of unloader bracing for people with normally aligned knees such as those after articular cartilage repair.
在进行胫股关节软骨修复后，通常会使用减压膝关节支具。然而，对于那些具有正常胫股排列的患者（如进行软骨修复的患者），使用减压支具的实验基础尚缺乏。
问题/目的：本研究的目的是探讨在正常膝关节排列的人群中，一种市售的减压膝关节支具的内翻和外翻调整对胫股关节负荷和膝关节肌肉激活的影响。
分析了 20 名健康参与者（平均年龄 28.3 岁；体重指数 22.9kg/m2）的步态，分别在支具内翻和外翻以及无支具的情况下进行分析。计算了时空变量以及站立时的膝关节内收力矩和肌肉激活。还计算了一个定向共收缩比，以研究在膝关节内侧（相对于外侧）力矩臂处肌肉激活的相对变化。使用方差分析研究组间差异。可用的数量将提供 85%的效能，以检测支具状态与无支具状态相比，膝关节内收力矩（Nm/kg*m）增加或减少 0.05。
在可用的数量下，支具和非支具条件之间的动力学或肌肉活动参数没有差异。内翻（定向共收缩比 0.29，SD 0.21，效应大小 0.95，p=0.315）和外翻（定向共收缩比 0.28，SD 0.24，效应大小 0.93，p=0.315）支具条件均增加了外侧力矩臂肌肉的相对激活，与无支具相比（定向共收缩比 0.49，SD 0.21）。
结果显示，在进行内翻和外翻支具固定后，膝关节的动力学和肌肉激活策略不一致。尽管在这项初步研究中结果没有统计学意义，但观察到的效应大小的幅度为中等至较大，代表了未来工作的合适初步数据。内翻支具增加了预期的膝关节内收力矩；然而，它们产生了更偏向外侧的肌肉激活模式。外翻支具产生了更偏向外侧的肌肉激活模式；然而，它增加了膝关节内收力矩。
当评估膝关节动力学和肌肉激活的变化时，本研究显示出相互矛盾的结果，并对具有正常排列的膝关节（如关节软骨修复后）使用减压支具的疗效提出了质疑。
