Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong, People's Republic of China.
Gait Posture. 2013 Mar;37(3):457-9. doi: 10.1016/j.gaitpost.2012.07.028. Epub 2012 Aug 24.
Ankle-foot orthoses (AFOs) can improve gait in patients with hemiplegia. However, it is anecdotally known that excessive plantarflexion resistance of an AFO could induce undesired knee flexion at early stance. The aim of this study was to systematically investigate the effect of varying the degrees of plantarflexion resistance of an AFO on knee flexion angles at early stance in five subjects with chronic stroke who demonstrated two clear knee flexion peaks at early stance and swing. Each subject wore an experimental AFO constructed with an oil-damper type ankle joint and was instructed to walk at their self-selected walking speed under five plantarflexion resistance conditions. The sagittal plane ankle and knee joint kinematics and gait speed were analyzed using a 3-D Motion Analysis System. A number of significant differences (P<0.005) in maximum knee flexion angles at early stance amongst different plantarflexion resistance conditions were revealed. The knee flexion angle was 23.80 (3.25) degrees under the free hinge joint condition (condition 1), while that was 26.09 (3.79) degrees under the largest resistance condition (condition 5). It was therefore demonstrated that increasing the plantarflexion resistance of an AFO would induce more knee flexion at early stance phase in patients with stroke.
踝足矫形器（AFO）可以改善偏瘫患者的步态。然而，据了解，AFO 的过度跖屈阻力可能会导致早期站立时不期望的膝关节屈曲。本研究的目的是系统地研究改变 AFO 的跖屈阻力程度对 5 名慢性卒中患者早期站立时膝关节屈曲角度的影响，这些患者在早期站立和摆动时有两个明显的膝关节屈曲峰。每位受试者均穿着由油阻尼式踝关节制成的实验性 AFO，并在五种跖屈阻力条件下以自身选择的步行速度进行行走。使用 3D 运动分析系统分析矢状面踝关节和膝关节运动学以及步行速度。在不同跖屈阻力条件下，早期站立时最大膝关节屈曲角度有许多显著差异（P<0.005）。在自由铰链关节条件下（条件 1），膝关节屈曲角度为 23.80（3.25）度，而在最大阻力条件下（条件 5），膝关节屈曲角度为 26.09（3.79）度。因此，增加 AFO 的跖屈阻力会导致中风患者在早期站立阶段膝关节屈曲更多。
