McNealy Lexyne L, Gard Steven A
Department of Biomedical Engineering,, Northwestern University, Evanston, Illinois, USA.
Prosthet Orthot Int. 2008 Mar;32(1):111-26. doi: 10.1080/02699200701847244.
In able-bodied individuals, the ankle joint functions to provide shock absorption, aid in foot clearance during the swing phase, and provides a rocker mechanism during stance phase to facilitate forward progression of the body. Prosthetic ankles currently used by persons with lower limb amputations provide considerably less function than their anatomical counterparts. However, increased ankle motion in the sagittal plane may improve the gait of persons with lower limb amputations while providing a more versatile prosthesis. The primary aim of this study was to examine and quantify temporal-spatial, kinematic, and kinetic changes in the gait of four male subjects with bilateral trans-femoral amputations who walked with and without prosthetic ankle units. Two prosthesis configurations were examined: (i) Baseline with only two Seattle LightFoot2 prosthetic feet, and (ii) with the addition of Endolite Multiflex Ankle units. Data from the gait analyses were compared between prosthetic configurations and with a control group of able-bodied subjects. The amputee subjects' freely-selected walking speeds, 0.74 +/- 0.19 m/s for the Baseline condition and 0.81 +/- 0.15 m/s with the ankle units, were much less than that of the control subjects (1.35 +/- 0.10 m/s). The amputee subjects demonstrated no difference in walking speed, step length, cadence, or ankle, knee, and hip joint moments and powers between the two prosthesis configurations. Sagittal plane ankle range of motion, however, increased by 3-8 degrees with the addition of the prosthetic ankle units. Compared to the control group, following initial contact the amputee subjects passively increased the rate of energy storage or dissipation at the prosthetic ankle joint, actively increased the power generation at the hip, and increased the extension moment at the hip while wearing the prosthetic ankle configuration. The amputee subjects increased the power generation at their hips, possibly as compensation for the reduced rate of energy return at their prosthetic ankles. Results from subject questionnaires administered following the gait analyses revealed that the prosthetic ankle units provided more comfort during gait and did not increase the perceived effort to walk. The subjects also indicated that they preferred walking with the prosthetic ankle units compared to the Baseline configuration. The results of the study showed that the prosthetic ankle units improved sagittal plane ankle range of motion and increased the comfort and functionality of the amputee subjects' prostheses by restoring a significant portion of the ankle rocker mechanism during stance phase. Therefore, prosthetic ankle mechanisms should be considered a worthwhile option when prostheses are prescribed for persons with trans-femoral amputations.
在健全个体中，踝关节起到减震作用，在摆动期辅助足部离地，并在站立期提供一种摇杆机制以促进身体向前行进。目前下肢截肢者使用的假踝关节所提供的功能远不及正常解剖结构的踝关节。然而，矢状面踝关节活动度的增加可能会改善下肢截肢者的步态，同时提供一种功能更丰富的假肢。本研究的主要目的是检查和量化四名双侧经股骨截肢男性受试者在佩戴和不佩戴假踝关节装置行走时步态在时空、运动学和动力学方面的变化。研究了两种假肢配置：(i) 仅配备两只西雅图LightFoot2假脚的基线配置，以及 (ii) 增加了Endolite Multiflex踝关节装置的配置。将步态分析的数据在不同假肢配置之间以及与一组健全受试者的对照组进行比较。截肢受试者自由选择的步行速度，基线配置时为0.74±0.19米/秒，佩戴踝关节装置时为0.81±0.15米/秒，远低于对照组受试者（1.35±0.10米/秒）。截肢受试者在两种假肢配置之间的步行速度、步长、步频或踝关节、膝关节和髋关节的力矩及功率方面没有差异。然而，增加假踝关节装置后，矢状面踝关节活动度增加了3 - 8度。与对照组相比，在初始接触后，截肢受试者在佩戴假踝关节配置时被动增加了假踝关节处能量储存或消散的速率，主动增加了髋关节处的功率产生，并增加了髋关节处的伸展力矩。截肢受试者增加了髋关节处的功率产生，可能是为了补偿假踝关节处能量返回速率的降低。步态分析后进行的受试者问卷调查结果显示，假踝关节装置在步态过程中提供了更多舒适度，且没有增加行走时的主观用力感。受试者还表示，与基线配置相比，他们更喜欢佩戴假踝关节装置行走。研究结果表明，假踝关节装置改善了矢状面踝关节活动度，并通过在站立期恢复大部分踝关节摇杆机制，提高了截肢受试者假肢的舒适度和功能。因此，在为经股骨截肢者开处方配置假肢时，假踝关节机制应被视为一个值得考虑的选择。
