Auto Control of Volume Management for Limb Loss

University of Washington

Status: Completed

Conditions: Lower Limb Amputation Below Knee (Injury)

Treatments: Device: Adjustable socket

Study type: Interventional

Funder types: Other

Identifiers

NCT03550118

STUDY00001779

Details and patient eligibility

About

The aim of this research is to create a prosthetic system that will automatically adjust the fit of the socket and create a well-fitting prosthesis for people with leg amputations who experience volume fluctuations when using their prosthesis.

Full description

People with lower limb amputations often experience daily changes in the size (volume) of their residual limb. These daily changes can cause a prosthesis to fit poorly. They can also cause limb health problems including skin breakdown and injury to deeper tissues. Prosthetic socket systems that accommodate limb volume changes can help address these issues, but they require users to make adjustments throughout the day.

The objective of this research is to develop and test an automatically-adjusting prosthetic socket system for prosthesis users. The system integrates with a range of adjustable socket technologies, including those that are commercially available. The system allows small size adjustments for both tightening and loosening the socket. In early aims of the study, the prosthesis will be adjusted manually, but can be controlled remotely, eliminating the need to remove the prosthesis or bend down to make adjustments. The system will later be enhanced to automatically change the fit of an adjustable socket at the appropriate times, without distracting the user. We hypothesize that this system will help to maintain consistent limb fluid volume while the prosthesis user is wearing the socket and that socket fit will be improved. The system functions by continuously collecting measurements from sensors within the socket and uses small motors to control adjustable panels in the socket wall.

Enrollment: 104 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• 18 years of age or older
• Unilateral transtibial amputee
• At least 6 months post-amputation
• Wear prosthesis at least 3 hours per day
• Use an elastomeric (i.e. gel) liner
• K3 or higher Medicare Functional Classification Level
• Able to walk continuously with prosthesis for at least 5 minutes at a time, sit, stand, and step up a height of 5.0 cm.
• Residual limb of 9.0 cm or longer
• Experience problems with volume fluctuations that affect their prosthetic socket fit

Exclusion criteria

• Participants experiencing skin breakdown on enrollment will be excluded, but can enter after having been free of clinically visually-apparent skin breakdown for two weeks.

Trial design

Primary purpose: Supportive Care

Allocation: Non-Randomized

Interventional model: Single Group Assignment

Masking: None (Open label)

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104 participants in 8 patient groups

Aim 2 - Adjustable Socket - Researcher Controls

Experimental group

Description:

An adjustable socket is tested where researchers control the adjustments. This arm focuses on socket size adjustments while walking.

Treatment:

Device: Adjustable socket

Aim 3 - Adjustable Socket - Participant Controls

Experimental group

Description:

An adjustable socket is tested where the study participant controls the adjustments. This arm focuses on socket size adjustments while walking.

Treatment:

Device: Adjustable socket

Aim 4 - Adjustable Socket - Automatic Controls

Experimental group

Description:

An adjustable socket is tested where a control system is used to automatically control the adjustments. This arm focuses on socket size adjustments while walking.

Treatment:

Device: Adjustable socket

Aim 6A - Release/Recovery - Researcher Controls

Experimental group

Description:

An adjustable socket is tested where researchers control the adjustments. This arm focuses on a socket release and recovery mechanism that allows for full or partial doffing of the socket while seated.

Treatment:

Device: Adjustable socket

Aim 6B - Release/Recovery - Participant Controls

Experimental group

Description:

An adjustable socket is tested where the study participant controls the adjustments. This arm focuses on a socket release and recovery mechanism that allows for full or partial doffing of the socket while seated.

Treatment:

Device: Adjustable socket

Aim 8 - Panel Pull During Resting

Experimental group

Description:

The purpose of Aim #8 was to determine if vacuum-like action ("panel pull") during resting between periods of activity facilitated limb fluid volume recovery and retention in transtibial prosthesis users. Liner attached to panels.

Treatment:

Device: Adjustable socket

Aim 9 - Panel Pull During Ambulation

Experimental group

Description:

Extending from the Aim #8 results, we sought to determine in Aim #9 if "vacuum-like" action during ambulation facilitated limb fluid volume recovery and retention. Vacuum-like action was achieved by quickly pulling the panels and liner (liner attached to panels) radially outward during late stance phase and then moving them back to their original position during early swing.

Treatment:

Device: Adjustable socket

Aim 10 - Adjustable Socket Out of Lab Testing

Experimental group

Description:

Participants took the investigational device home in one of three test modes. In the first mode, the panels were in a "locked" flush position, similar to their traditional prosthesis. Participants were not able to adjust the panels in this first mode. The second mode allowed participants to manually make panel adjustments, incrementally enlarging or tightening the panels radially. Lastly, the third mode implemented the automated controller developed in the previous aims. Participants were still able to make manual adjustments to the panel positions but during walks adjustments would also occur automatically. Each mode was tested for a minimum of 1 week.

Treatment:

Device: Adjustable socket