Do Adaptable Sockets Improve Military Performance?

Summary

This is a repeated measures prospective study and is no greater than a minimal risk study. All study procedures will be conducted at the Center for the Intrepid (CFI) through collaborative efforts of the Military Performance Lab at the CFI and the Sanders lab at the University of Washington. Data collected at the CFI will be coded, compiled, and shared with the University of Washington investigators.The objective of the research is to test if microprocessor-adjusting sockets improve Service member performance in Military specific activities compared to (a) user- operated, motor-driven adjustable sockets (i.e. sockets users adjust themselves), and (b) static (traditional) sockets. Investigators also test if microprocessor-adjusting sockets better maintain socket fit and limb fluid volume, and if self-reported outcomes are more favorable than for user-operated or static sockets. The hypotheses to be tested include:

During intense Military specific tasks, compared to the user-adjusted socket and the static socket, the microprocessor-adjusting socket will:

1. minimize translational movement between the residual limb and the prosthetic socket;
2. maintain residual limb fluid volume; and
3. maximize prosthetic socket comfort.

When using the microprocessor-adjusting socket compared to the user-adjusted socket and the static socket, participants will:

1. cover the greatest distance during a simulated combat patrol;
2. perform all high intensity Military specific tasks with less pain;
3. perform a simulated combat patrol nearer to uninjured levels of performance; and
4. rank usability at a level similar to the static socket.

The specific aims are to:

1. Fabricate microprocessor-adjusting sockets specific for Service members and Veterans with goals of returning to high-level physical activities
2. Evaluate Military task performance in Service members with transtibial amputation using "Readiness Assessments," while wearing three socket configurations: microprocessor-adjusting, user-adjusting, and static

* Simulated combat patrol in a Virtual Realty Environment
* Military version of a Functional Capacity Evaluation
3. Characterize user preference and usability of different socket configurations

Conditions

• Amputation Stump

Interventions

DEVICE

Static socket

For the static socket configuration, both the microprocessor control and user control are disabled, and the panels are positioned in their flush configuration to create the user's as-prescribed socket shape.

DEVICE

User adjusted socket

Sockets are configured for user control by disabling automated control and enabling push buttons on the side of the socket to adjust socket size. Each button push effects a socket size change of approximately 0.3% volume. An upper button effects a socket size increase, and a lower button a socket size decrease. The buttons are countersunk so reduce risk of accidental pushes, and they do not function unless the user is stationary. An additional button push will not be executed until motor motion from the prior push has been completed. If a button is continuously held then the motor will continue moving until the button is released. Limits are set on cable length to ensure that sockets sizes threatening to the user's residual limb (too tight) are avoided. The push buttons effect inner-loop control that operates completely within the mechanism, achieving high-resolution adjustment of cable length with minimal error.

DEVICE

Microprocessor-adjusting sockets

A strategy for automatically controlling the size of the socket during walking to compensate for unknown changes in limb volume will be used. The controller is essentially a regulator that continuously measures socket "fit," and adjusts the socket to maintain a prescribed reference set point. Because the fit is automatically sustained, the prosthesis user is unaware of its operation.

Sponsors & Collaborators

• University of Washington

  collaborator OTHER

• Brooke Army Medical Center

  lead FED

Principal Investigators

• Walter L Childers, PhD · Extremity Trauma and Amputation Center of Excellence (EACE)

Study Design

Allocation

NA

Purpose

TREATMENT

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Max Age

55 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2020-11-04

Primary Completion

2024-01-10

Completion

2024-01-10

Countries

• United States

Study Locations