A Practical Approach for Evaluation of Socket Pistoning for Lower Limb Amputees

Area of Science:

• Biomedical Engineering
• Rehabilitation Technology
• Prosthetics and Orthotics

Background:

• Socket-suspension system fit is critical for lower limb amputees' mobility and comfort.
• Current methods for monitoring socket fit rely on subjective user feedback, which is often unreliable.
• Measuring pistoning, the relative motion between the residual limb and socket, is a key indicator of fit but challenging due to socket properties.

Purpose of the Study:

• To develop and evaluate a novel procedure for objectively measuring pistoning in prosthetic sockets.
• To provide a reliable, non-invasive method for assessing socket-suspension system fit in lower limb amputees.

Main Methods:

• Development of a pistoning evaluation procedure utilizing synchronized magnetic and optical motion capture systems.
• Magnetic motion capture tracked residual limb movement; optical motion capture tracked socket movement.
• Synchronization of both systems allowed for precise calculation of relative displacement (pistoning amplitude).

Main Results:

• The developed procedure successfully measured pistoning amplitude during treadmill walking with a lower limb amputee.
• The method demonstrated reliable performance through repeated calibration.
• This approach offers an alternative to radiography-based methods for pistoning evaluation.

Conclusions:

• The synchronized dual motion capture system procedure provides an objective and reliable method for evaluating prosthetic socket fit.
• This non-radiographic technique can be applied to assess the fit of everyday prosthetic sockets for lower limb amputees.
• Improved objective fit assessment can lead to better prosthetic limb outcomes and user satisfaction.