Whole-body angular momentum during stair walking using passive and powered lower-limb prostheses

Area of Science:

• Biomechanics
• Rehabilitation Engineering
• Prosthetics

Background:

• Individuals with unilateral transtibial amputation face higher fall risks, especially on stairs, due to lost ankle plantarflexor function crucial for dynamic balance.
• Powered prostheses aim to restore ankle function, but their impact on whole-body angular momentum regulation during stair ambulation remains unclear.

Purpose of the Study:

• To evaluate dynamic balance in transtibial amputees using powered versus passive prostheses during stair ascent and descent.
• To analyze angular momentum, ground reaction forces, and joint powers to understand balance control mechanisms.

Main Methods:

• Comparative analysis of angular momentum regulation during stair ascent and descent.
• Inclusion of individuals with unilateral transtibial amputation (using powered and passive prostheses) and able-bodied controls.
• Measurement of ground reaction forces, external moment arms, and joint powers.

Main Results:

• Amputees demonstrated a wider range of sagittal-plane angular momentum during prosthetic limb stance on stairs compared to able-bodied individuals.
• No significant differences were found in angular momentum ranges or maximum magnitudes between powered and passive prostheses during stair ascent or descent.
• Altered angular momentum trajectories were observed in amputees during stair walking.

Conclusions:

• Individuals with transtibial amputations exhibit altered dynamic balance control during stair walking, potentially contributing to increased fall risk.
• Current powered prostheses do not offer a significant advantage over passive prostheses in enhancing dynamic balance during stair ambulation.