Russell Esposito Elizabeth, Aldridge Whitehead Jennifer M, Wilken Jason M
Center for the Intrepid, Brooke Army Medical Center, Fort Sam Houston, TX, USA
Center for the Intrepid, Brooke Army Medical Center, Fort Sam Houston, TX, USA.
Prosthet Orthot Int. 2016 Jun;40(3):311-9. doi: 10.1177/0309364614564021. Epub 2015 Jan 27.
Individuals with leg amputations who use passive prostheses have greater metabolic demands than non-amputees likely due to limited net positive work compared to a biological ankle. New powered ankle-foot prostheses can perform net positive mechanical work to aid push-off capabilities, which may reduce metabolic demands.
Compare step-to-step transition work and metabolic demand during level and inclined walking using passive and powered ankle-foot prostheses.
Repeated measures.
Six individuals with transtibial amputation and six able-bodied controls walked at a standardized speed across level ground and up a 5° incline. Calculated measures included mechanical work during step-to-step transitions from the trailing prosthetic to leading intact limb, steady state metabolic rate, and ankle joint kinetics and kinematics.
The powered prosthesis generated 63% greater trailing limb step-to-step transition work than the passive during level walking only (p = 0.004). Metabolic rate was lower with the powered prosthesis during level (p = 0.006) but not inclined walking (p = 0.281). The powered prosthesis increased ankle power compared to the passive, to the extent that power was normalized to controls during inclined walking and greater than controls during level walking.
The powered prosthesis improved ankle power, metabolic rate, and step-to-step transition work on level ground, with few negative consequences on inclines. These results may be used to guide the development and use of actively powered prosthetic devices in high-functioning individuals.
Overall, powered devices offer biomechanical and metabolic benefits over passive energy storage and return designs on level ground and perform as well as a passive model on inclines. The lower metabolic demand when using the powered device may delay fatigue for individuals with transtibial amputation when walking over level ground.
使用被动假肢的下肢截肢者比非截肢者有更高的代谢需求，这可能是因为与生物脚踝相比，其净正功有限。新型动力脚踝足假肢可以进行净正机械功以辅助蹬离能力，这可能会降低代谢需求。
比较使用被动和动力脚踝足假肢在平路和上坡行走时的逐步步态转换功和代谢需求。
重复测量。
6名经胫截肢者和6名健全对照者以标准化速度在平地上行走并爬上5°斜坡。计算的指标包括从后置假肢到前置健全肢体的逐步步态转换过程中的机械功、稳态代谢率以及踝关节动力学和运动学。
仅在平路行走时，动力假肢产生的后置肢体逐步步态转换功比被动假肢大63%（p = 0.004）。在平路行走时，动力假肢的代谢率较低（p = 0.006），但在上坡行走时无差异（p = 0.281）。与被动假肢相比，动力假肢增加了踝关节功率，在上坡行走时功率与对照者相当，在平路行走时大于对照者。
动力假肢在平地上改善了踝关节功率、代谢率和逐步步态转换功，在上坡时负面影响较小。这些结果可用于指导高功能个体中主动动力假肢装置的开发和使用。
总体而言，动力装置在平地上比被动储能和回能设计具有生物力学和代谢优势，在上坡时表现与被动模型相当。使用动力装置时较低的代谢需求可能会延迟经胫截肢者在平路行走时的疲劳。
