Prosthetic gait of unilateral transtibial amputees with current and novel prostheses

INTRODUCTION

Novel lower-limb prostheses aim to improve the quality of locomotion of individuals with an amputation. The current study evaluates a novel bionic foot, i.e. the Ankle Mimicking Prosthetic foot (AMPfoot) 4.0 in terms of kinetics and kinematics during normal speed walking. Improved gait kinetics and kinematics were hypothesised, especially at the level of the ankle.

METHODS

Able-bodied individuals (5 men, 2 women, age: 26 yr (SD 5), height: 1.75 m (SD 0.10) and weight: 72 kg (SD 12)) and individuals with an amputation below knee (TTA: 6 men, age: 54 yr (SD 14), height: 1.76 m (SD 0.08) and weight: 80 kg (SD 13)) were included. AbleOP- BN05 Gait I 176 24TH ANNUAL CONGRESS OF THE EUROPEAN COLLEGE OF SPORT SCIENCE bodied individuals conducted one experimental trial, whereas TTA conducted a familiarization and two experimental trials; experiment 1 with the current, passive prosthesis and experiment 2 with AMPfoot 4.0. Each trial included a 2-minute normal speed walking task. Biomechanical data was gathered using a force platform embedded in the treadmill and a motion capture system using a 6-camera VICON MX F20 system. Data were analysed using 1D Statistical Parametric Mapping and (non)-parametric tests. Significance level was set at 0.05.

RESULTS

Walking with the current prosthesis at normal speed reduced maximal heel forces (P<0.001) and increased ankle angle velocity and trunk sagittal velocity at midstance (P≤0.011), and knee angle (P≤0.026). Walking with AMPfoot on the other hand, did not elicit significant alterations of these parameters, with the exeption that AMPfoot reduced maximal heel force (P=0.004). Furthermore, walking with AMPfoot at normal speed significantly reduced stride length (P=0.01), and significantly altered trunk sagittal angle and velocity during the swing phase (P≤0.047). These differences did not occur when comparing able-bodied walking and walking with the current prosthesis.

CONCLUSION

As hypothesized, TTA walking with the AMPfoot 4.0 better mimics gait characteristics of able-bodied walking compared to the conventional prosthesis during normal speed walking. Three-dimensional motion capture data of TTA walking with the current prosthesis demonstrates significant alterations compared to able-bodied walking. Walking with the AMPfoot also resulted in altered gait characteristics compared to able-bodied walking. However, these alterations were subtler and less disturbing than during walking with the current prosthesis. Conventional prosthetic feet do not provide the required dorsi- and plantarflexion, which leads to altered gait patterns and locomotion difficulties. This is countered through the mechanics of AMPfoot 4.0. Thus, TTA walking with AMPfoot 4.0 better mimics able-bodied walking.