Step-to-step transition work during level and inclined walking using passive and powered ankle–foot prostheses. (June 2016)

• Record Type: Journal Article
• Authors: Russell Esposito, Elizabeth; Aldridge Whitehead, Jennifer M; Wilken, Jason M
• Is Part Of: Prosthetics and orthotics international. Volume 40:Number 3(2016:Jun.)
• Page Start: 311
• Page End: 319
• Publication Date: 2016-06
• Subjects: Energetics -- transtibial -- hill -- biomechanics; Orthopedic apparatus -- Periodicals; Prosthesis -- Periodicals; Implants, Artificial -- Periodicals; 617.905
• DOI: 10.1177/0309364614564021
• Languages: English
• ISSNs: 0309-3646

Abstract

Background: 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. Objectives: Compare step-to-step transition work and metabolic demand during level and inclined walking using passive and powered ankle-foot prostheses. Study Design: Repeated measures. Methods: 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. Results: 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. Conclusion: 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. Clinical relevance: 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.