Lower Limb Amputation Below Knee (Injury)NCT03550118
Auto Control of Volume Management for Limb Loss
A study testing Adjustable socket in people with Lower Limb Amputation Below Knee (Injury), run by University of Washington at 1 site in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Lower Limb Amputation Below Knee (Injury)
- What is being tested?
- Adjustable socket
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 104 participants
- Where
- 1 siteUnited States
- Study dates
- 7 Aug 2015to Jan 2022
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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
Show all 9Show fewer
- 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
Who cannot join
- 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 locations and contacts
1 site in 1 country.
United States1 site
University of Washington Bioengineering
Seattle, Washington, 98195
About this study
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.
Read the detailed 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.
- Being tested
- Adjustable socket
- Keywords
- Prosthetic Socket, Amputee, Adjustable Socket
- Medical subject headings
- Wounds and Injuries
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Adjustable socketDevice
The adjustable prosthetic socket will be used to test the influence of socket size adjustments during sitting, standing, and walking activities to determine if these strategies can be used to improve socket fit and reduce fluctuations in limb volume.
| Study group | Role | What they receive |
|---|---|---|
| Aim 2 - Adjustable Socket - Researcher Controls | Experimental | An adjustable socket is tested where researchers control the adjustments. This arm focuses on socket size adjustments while walking. Receives: Device: Adjustable socket |
| Aim 3 - Adjustable Socket - Participant Controls | Experimental | An adjustable socket is tested where the study participant controls the adjustments. This arm focuses on socket size adjustments while walking. Receives: Device: Adjustable socket |
| Aim 4 - Adjustable Socket - Automatic Controls | Experimental | 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. Receives: Device: Adjustable socket |
| Aim 6A - Release/Recovery - Researcher Controls | Experimental | 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. Receives: Device: Adjustable socket |
| Aim 6B - Release/Recovery - Participant Controls | Experimental | 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. Receives: Device: Adjustable socket |
| Aim 8 - Panel Pull During Resting | Experimental | 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. Receives: Device: Adjustable socket |
| Aim 9 - Panel Pull During Ambulation | Experimental | 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. Receives: Device: Adjustable socket |
| Aim 10 - Adjustable Socket Out of Lab Testing | Experimental | 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. Receives: Device: Adjustable socket |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Limb Volume
Limb volume fluctuations will be measured in real-time as socket adjustment strategies are tested. This will be accomplished using a portable bioimpedance device with thin sticky electrodes that are placed on the residual limb. Specifically, the change in limb volume will be assessed from a baseline period where no socket adjustments are made to another period within the same test session where socket adjustments are made.
Measured: Change from baseline period (non-adjustment) to test period (adjustment), commonly each 1 hour long and separated by a seated period of approximately 30 minutes.
Change in Limb Movement
Limb movement within the socket will be measured as socket adjustment strategies are tested. It will be used as an indicator of how well the socket is fitting (loose, tight, etc). The measurement will be made using an inductance sensor that is placed in the socket which measures the displacement of a sensor patch on the prosthetic liner. Specifically, the change in limb movement will be assessed from a baseline period where no socket adjustments are made to another period within the same test session where socket adjustments are made.
Measured: Change from baseline period (non-adjustment) to test period (adjustment), commonly each 1 hour long and separated by a seated period of approximately 30 minutes.
Number of Participants With Increase in Limb Fluid Volume After Panel Pull
Limb volume fluctuations will be measured in real-time as socket adjustment strategies are tested. This will be accomplished using a portable bioimpedance device with thin sticky electrodes that are placed on the residual limb. Specifically, the change in limb volume will be assessed from a baseline period where no socket adjustments are made to another period within the same test session where socket adjustments are made.
Measured: Change from baseline period (non-adjustment) to test period (adjustment), commonly each 1 hour long and separated by a seated period of approximately 30 minutes.
Integral of Absolute Error to Maintain Set Point
Clinically acceptable socket volume error as measured by an automatically adjusting prosthetic socket attempting to maintain a set socket volume set point, based on sensed distance (measured in mm).
Measured: Over 30 minutes of controlled use of the auto-adjusting socket
Secondary outcomes (1)
Adjustable Socket Mode Preference
Participants tested the adjustable prosthesis in their home environment in one of three adjustment configurations:
- "locked" where panels were kept in position and did not move, similar to their own prosthesis
- "manual" where panels were able to be adjusted inward or outward radially, by the participant via a phone app
- "automatic" where panels adjusted inward or outward radially as when the participant walked for a sufficiently continuous amount of time. Participants were also able to manual adjust panels as needed in this mode as well.
Measured: After 3 weeks of use, where each mode was tested for about 1 week
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Jun 2018
- Study start7 Aug 2015
- Primary completionSep 2021
- Study completionJan 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Lower Limb Amputation Below Knee (Injury)Studies of the same condition, open and under way.
- More trials run by University of WashingtonThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Supportive care
- Allocation
- Non-randomised
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 104 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Washington
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Joan Sanders, University of Washington
- Investigators
- Joan E Sanders, PhD, Principal investigator, University of Washington
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03550118
- Sponsor's protocol ID
- STUDY00001779
- Status last verified
- Apr 2023
- First submitted
- 3 May 2018
- Last updated
- 3 May 2023
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 3 May 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Auto Control of Volume Management for Limb Loss
- ClinicalTrials.gov ID
- NCT03550118
- Acronym / sponsor ID
- STUDY00001779
- Keywords
- Prosthetic Socket, Amputee, Adjustable Socket
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 104 participants (actual)
- Lead sponsor
- University of WashingtonUniversity, hospital or other
- Study start
- 7 Aug 2015 (actual)
- Primary completion
- Sep 2021 (actual)
- Study completion
- Jan 2022 (actual)
- First posted
- 8 Jun 2018 (actual)
- Results
- Posted 3 May 2023
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed 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.
Study design
- Primary purpose
- Supportive care
- Allocation
- Non-randomised
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 8
| Arm | Type | Receives |
|---|---|---|
| Aim 2 - Adjustable Socket - Researcher Controls | Experimental | Device: Adjustable socketAn adjustable socket is tested where researchers control the adjustments. This arm focuses on socket size adjustments while walking. |
| Aim 3 - Adjustable Socket - Participant Controls | Experimental | Device: Adjustable socketAn adjustable socket is tested where the study participant controls the adjustments. This arm focuses on socket size adjustments while walking. |
| Aim 4 - Adjustable Socket - Automatic Controls | Experimental | Device: Adjustable socketAn adjustable socket is tested where a control system is used to automatically control the adjustments. This arm focuses on socket size adjustments while walking. |
| Aim 6A - Release/Recovery - Researcher Controls | Experimental | Device: Adjustable socketAn 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. |
| Aim 6B - Release/Recovery - Participant Controls | Experimental | Device: Adjustable socketAn 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. |
| Aim 8 - Panel Pull During Resting | Experimental | Device: Adjustable socketThe 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. |
| Aim 9 - Panel Pull During Ambulation | Experimental | Device: Adjustable socketExtending 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. |
| Aim 10 - Adjustable Socket Out of Lab Testing | Experimental | Device: Adjustable socketParticipants 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. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (9 listed)
- 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
Key exclusion criteria (1 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Adjustable socketThe adjustable prosthetic socket will be used to test the influence of socket size adjustments during sitting, standing, and walking activities to determine if these strategies can be used to improve socket fit and reduce fluctuations in limb volume. | Device | Aim 10 - Adjustable Socket Out of Lab Testing, Aim 2 - Adjustable Socket - Researcher Controls, Aim 3 - Adjustable Socket - Participant Controls, Aim 4 - Adjustable Socket - Automatic Controls, Aim 6A - Release/Recovery - Researcher Controls, Aim 6B - Release/Recovery - Participant Controls, Aim 8 - Panel Pull During Resting, Aim 9 - Panel Pull During Ambulation |
Primary outcome
Change in Limb Volume
Time frame: Change from baseline period (non-adjustment) to test period (adjustment), commonly each 1 hour long and separated by a seated period of approximately 30 minutes.
Limb volume fluctuations will be measured in real-time as socket adjustment strategies are tested. This will be accomplished using a portable bioimpedance device with thin sticky electrodes that are placed on the residual limb. Specifically, the change in limb volume will be assessed from a baseline period where no socket adjustments are made to another period within the same test session where socket adjustments are made.
Change in Limb Movement
Time frame: Change from baseline period (non-adjustment) to test period (adjustment), commonly each 1 hour long and separated by a seated period of approximately 30 minutes.
Limb movement within the socket will be measured as socket adjustment strategies are tested. It will be used as an indicator of how well the socket is fitting (loose, tight, etc). The measurement will be made using an inductance sensor that is placed in the socket which measures the displacement of a sensor patch on the prosthetic liner. Specifically, the change in limb movement will be assessed from a baseline period where no socket adjustments are made to another period within the same test session where socket adjustments are made.
Number of Participants With Increase in Limb Fluid Volume After Panel Pull
Time frame: Change from baseline period (non-adjustment) to test period (adjustment), commonly each 1 hour long and separated by a seated period of approximately 30 minutes.
Limb volume fluctuations will be measured in real-time as socket adjustment strategies are tested. This will be accomplished using a portable bioimpedance device with thin sticky electrodes that are placed on the residual limb. Specifically, the change in limb volume will be assessed from a baseline period where no socket adjustments are made to another period within the same test session where socket adjustments are made.
Integral of Absolute Error to Maintain Set Point
Time frame: Over 30 minutes of controlled use of the auto-adjusting socket
Clinically acceptable socket volume error as measured by an automatically adjusting prosthetic socket attempting to maintain a set socket volume set point, based on sensed distance (measured in mm).
1 secondary outcome
Adjustable Socket Mode Preference
Time frame: After 3 weeks of use, where each mode was tested for about 1 week
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 May 2023.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Joan E Sanders, PhD principal investigator
University of Washington
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Adjustable socket in people with Lower Limb Amputation Below Knee (Injury), run by University of Washington at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 3 May 2023. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 3 May 2023). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Limb Volume (time frame: Change from baseline period (non-adjustment) to test period (adjustment), commonly each 1 hour long and separated by a seated period of approximately 30 minutes.). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 May 2023; AzTrials last refreshed its copy on 6 Nov 2026.