Microprocessor prosthetic ankles: comparative biomechanical evaluation of people with transtibial traumatic amputation during standing on level ground and slope

Abstract

Background: The compensations occurrence due to the alteration of the posture and the gait of persons with lower limb amputation is still an issue in prosthetic fitting. Recently, prosthetic feet designed to reproduce the physiological behaviour of the ankle using a microprocessor control have been commercialized to address this issue. Objectives: Investigate the relevance of these microprocessor prosthetic ankles (MPAs) in the ability of standing on both level and inclined surfaces. Methods: Six persons with transtibial amputation usually fitted with energy storing and returning (ESR) foot tested three MPAs: Elan V R Endolite (MPA1), Meridium V R Ottobock (MPA2), ProprioFoot V R Ossur (MPA3). Each MPA data acquisition was preceded of a 2 weeks adaptation period at home and followed by a 3weeks wash-out period with their ESR. Lower limb angular position and moment, Centre of Pressure (CoP) position, Ground Reaction Forces (GRF) and functional scores were collected in static, on level ground and 12% inclined slope. Results: MPAs allowed a better posture and a reduction of residual knee moment on positive and/or negative slope compared to ESR. Results also reflect that the MPA2 allows the best control of the CoP in all situations. Conclusions: An increased ankle mobility is associated with a better posture and balance on slope. Gait analysis would complete these outcomes. Clinical relevance: This study compares three MPAs to ESR analysing static posture. Static analysis on level ground and slope represents the challenging conditions people with amputation have to cope with in their daily life, especially outdoors. Having a better understanding of the three MPAs behaviour could help to adequately fit the prosthesis to each patient.

Quantification of the Influence of Prosthetic Ankle Stiffness on Static Balance Using Lower Limb Prosthetic Simulators

“…Thus, the stiffness of a foot prosthesis should be a compromise to allow walking and balance during standing. A solution would be a bimodal prosthesis [20] or a prosthesis with adaptive stiffness [38], but for an active prosthesis, the control must be fast and accurate. Moreover, active prostheses are more expensive than passive prostheses.…”

Evaluation of Biomechanical Effects and Patient Benefits of a New Orthotic Ankle Joint in Stance Control Orthosis Fittings

“…Future studies should investigate whether this improved kinetic characteristic is correlated with reduced metabolic energy consumption, as has been shown for the SCO principle compared with locked KAFOs for ascending ramps with an inclination of 5°. 22 The specific tests for standing on slopes, established in prosthetics to evaluate prosthetic feet and knee joints, 23,24 seem to represent a difficult ADL for patients with complex lower-limb muscle weakness. However, such tests have been rarely described in orthotics.…”

“…The specific tests for standing on slopes, established in prosthetics to evaluate prosthetic feet and knee joints, 23,24 seem to represent a difficult ADL for patients with complex lower-limb muscle weakness. However, such tests have been rarely described in orthotics 12 .…”

Experimental characterization of the moment-angle curve during level and slope locomotion of transtibial amputee: Which parameters can be extracted to quantify the adaptations of microprocessor prosthetic ankle?

“…Suggestive feedbacks and clinical functional test have been investigated in the companion article published in 2019 by Thomas-Pohl et al 22 Basically, the participants found the MPAs heavier and less reactive for the propulsion.…”