Individuals with Unilateral Transtibial Amputation and Lower Activity Levels Walk More Quickly when Using a Hydraulically Articulating Versus Rigidly Attached Prosthetic Ankle-Foot Device

Abstract

Introduction Prosthetic ankle-foot devices incorporating a hydraulic articulation between the pylon and prosthetic foot have been shown to be beneficial to the gait of more active individuals with unilateral transtibial amputation (UTA). However, the functional benefits of using hydraulic ankle-foot devices to less active individuals with UTA are yet to be determined. The aim of the current study was to investigate the effects on gait performance of using a non-ESR foot with a hydraulic attachment, compared to an identical, rigidly attached foot during overground walking in less active individuals with UTA. Materials and Methods Kinematic and kinetic data were recorded while five individuals with UTA, deemed K2 activity level by their prescribing physician, performed two-minute walk tests (2MWT) and ten overground gait trials, in two conditions; using a hydraulically articulating ankle foot device (HYD) and using a rigidly attached ankle foot device (RIG). Results Walking speed during the 2MWT was increased by 6.5% on average, in the HYD (1.07 m/s) condition, compared to the RIG (1.01 m/s) condition (Cohen's d = 0.4). Participants displayed more symmetrical inter-limb loading (d = 0.8), increased minimum forward centre of pressure velocity (d = 0.8), increased peak shank rotational velocity (d = 1.0) and decreased prosthetic energy efficiency (d = 0.7) when using the HYD compared to RIG device. Conclusions Individuals with lower activity levels walk faster and therefore further when, using a foot with a hydraulically articulating attachment, in comparison to a rigid attachment. A reduced braking effect in early stance phase, as a result of the action of the hydraulic component present in the articulating attachment, partially explains the improvement in walking performance.

Calculated functional joint center positions are highly variable in individuals with unilateral transtibial amputation walking with identical prosthetic ankle-foot devices

“…However, other approaches have been used to characterize the biomechanical function of prosthetic feet. In terms of kinematics, shank rotational velocity relative to a global horizontal axis 14 and center of pressure displacement and velocity 15 may provide information regarding the concept of progression during stance. From a kinetic perspective, methods that do not necessitate the definition of an ankle joint center to calculate ankle-foot complex power may be favorable.…”

The influence of a microprocessor-controlled hydraulic ankle on the kinetic symmetry of trans-tibial amputees during ramp walking: A case series

“…0:4 has been described as a 'medium' effect size 24 and past prosthetic research has defined this as being a clinically meaningful difference. 22,25 The statistical analyses were applied to comparisons between MI sup for MPF-on and MPF-off conditions, and only within walking conditions (e.g. MPF-on downhill vs. MPF-off downhill).…”

STEPFORWARD study: a randomised controlled feasibility trial of a self-aligning prosthetic ankle-foot for older patients with vascular-related amputations

“…This can improve ground clearance and secure the biological knee, which is important for falls prevention. 9 Previous laboratory-based studies reported that a self-aligning ankle-foot reduced residuum-socket interface pressures in active users, 10 which could alleviate pain in the residuum longer term, improved walking 11 and enhanced quality of life 12 13 in users with lower activity levels.…”