Auto-Adjusting Prosthetic Socket for Below Knee Amputation

Overseen By Katheryn Allen, CPO

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Washington

Disqualifiers: Neuropathy, reduced skin sensation, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Approved in 1 Jurisdiction This treatment is already approved in other countries

Compensation: Varies

Number of Visits: Unknown

100 Participants Needed

Trial Summary

What is the purpose of this trial?

People with leg 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 problems like pain or skin breakdown. Prosthetic socket systems that accommodate limb volume changes can help address these issues, but they require users to make adjustments throughout the day. The aim of this research is to create a 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.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications.

What data supports the effectiveness of the treatment Auto-Adjusting Prosthetic Socket for Below Knee Amputation?

Research shows that adjustable prosthetic sockets can help people with below-knee amputations maintain a better fit and comfort by allowing small size adjustments to accommodate changes in limb volume. This can improve the overall satisfaction and usability of the prosthesis, as users can adjust the fit while walking, which helps prevent discomfort and potential abandonment of the prosthesis. ^{1 2 3 4 5}

Is the auto-adjusting prosthetic socket safe for humans?

The research indicates that auto-adjusting prosthetic sockets have been tested for stability and comfort during walking, with most participants finding them comfortable to adjust while walking. No specific safety concerns were reported in the studies. ^{1 2 4 5 6}

How is the Auto-Adjusting Prosthetic Socket treatment different from other treatments for below-knee amputation?

The Auto-Adjusting Prosthetic Socket is unique because it allows users to adjust the fit of their prosthetic socket in small increments using a mobile phone app, which helps maintain comfort and fit as the residual limb changes in volume. This system uses a motor to adjust the socket size, providing a more personalized and adaptable fit compared to traditional static sockets. ^{1 2 4 5 7}

Research Team

Joan E Sanders, PhD

Principal Investigator

University of Washington

Eligibility Criteria

This trial is for adults who have had a below-knee amputation at least one year ago, regularly use a definitive prosthesis with pin lock suspension, and experience daily limb size changes. Certified prosthetists treating such patients can also participate. People using walking aids, with reduced skin sensation or neuropathy, or current sores on their residual limb cannot join.

Inclusion Criteria

Regularly use a definitive prosthesis with pin lock suspension and few or no pads (Prosthesis Users only)

I am 18 years old or older and use a prosthesis.

I had a below-the-knee amputation over a year ago and use a prosthesis.

Exclusion Criteria

Sores or skin breakdown on their residual limb (Prosthesis Users, Aim 2 and Aim 3 only)

Are not certified prosthetists (Prosthetists only)

Neuropathy (Prosthesis Users only)

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Focus Group Testing

Focus group testing of key-fob device to control adjusting socket system

4-6 weeks

Multiple visits (in-person)

In-Lab, Crossover Study

Testing of auto-adjusting algorithm in-lab with participants carrying out a structured protocol wearing the socket in all modes

3 months

Regular visits (in-person)

Out-of-Lab Crossover Study

Evaluate socket performance in user free-living environments with participants using the prosthesis in all modes

3 months

Regular check-ins (virtual and in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

Treatment Details

Interventions

• Auto Adjusting Prosthesis

Trial Overview The study tests an auto-adjusting prosthetic socket designed to automatically adapt to daily volume changes in the residual limbs of people with transtibial amputations, aiming to improve fit and comfort without manual adjustments.

Participant Groups

Group I: Out-of-Lab Crossover Study Experimental Treatment 1 Intervention

Evaluate socket performance in user free-living environments. Participants will use the prosthesis in all modes by end of study, order will be randomly assigned.

Group II: In-Lab, Crossover Study Experimental Treatment 1 Intervention

Testing of auto-adjusting algorithm in-lab. Participants will carry out a structured protocol wearing the socket in all modes. Order will be randomly assigned.

Group III: Focus Group Testing Active Control 1 Intervention

Focus group testing of key-fob device to control adjusting socket system

Auto Adjusting Prosthesis is already approved in United States for the following indications:

Approved in United States as Auto-Adjusting Prosthetic Socket for:

• Transtibial amputation
• Residual limb volume fluctuations

Who Is Running the Clinical Trial?

University of Washington

Lead Sponsor

Trials

1,858

Recruited

2,023,000+

Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

Collaborator

Trials

2,103

Recruited

2,760,000+

Findings from Research

In a study involving 10 participants with transtibial amputation, adjustable sockets allowed for real-time modifications that maintained limb fluid volume within a narrow range of -0.7% to +0.9% during walking, indicating effective management of limb fit.

Participants accepted socket sizes that varied from -5% to +5% of their neutral volume, demonstrating that small adjustments can significantly impact limb fluid volume and the distance between the limb and socket, suggesting potential for improved comfort and function in prosthetic use.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Socket size adjustments in people with transtibial amputation: Effects on residual limb fluid volume and limb-socket distance. McLean, JB., Redd, CB., Larsen, BG., et al.[2022]

A new adjustable socket system for prosthetic users allows for incremental size adjustments during walking, which can help improve fit and comfort for individuals with trans-tibial limb loss.

In tests with 16 participants, the system demonstrated precise adjustments with minimal error (0.036 mm) and was well-received, as 11 out of 13 users felt comfortable making adjustments while walking.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A motor-driven adjustable prosthetic socket operated using a mobile phone app: A technical note. Sanders, JE., Garbini, JL., McLean, JB., et al.[2019]

Adjustable prosthetic sockets have the potential to significantly improve fit and comfort for users, which is crucial for preventing prosthesis abandonment and enhancing community participation, as evidenced by a review of 50 literature articles and 63 patents.

Despite the promise of adjustable sockets, many designs lack adequate safety features and the rationale for their comfort improvements is often unclear, highlighting a need for better collaboration between researchers and industry to address these gaps.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Adjustable prosthetic sockets: a systematic review of industrial and research design characteristics and their justifications. Baldock, M., Pickard, N., Prince, M., et al.[2023]

The newly developed alignment device for below-knee prostheses allows for easy, independent adjustments of angle and slide even after the prosthetic has been manufactured, enhancing customization for users.

This device is lightweight, compact, and cost-effective, making it easier to cover cosmetically and providing significant advantages over existing designs in terms of functionality and reusability.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A new in-built device for one-point stepless prosthetic alignment. Köhler, P., Lind, L., Lind, K., et al.[2017]

The study tested an auto-adjusting prosthetic socket in six transtibial prosthesis users, demonstrating that the control system maintained stable operation during 98% of walking bouts, indicating its reliability.

The system effectively adjusted the socket size in response to changes in limb fluid volume, suggesting it is ready for further testing in real-world settings to enhance user comfort and fit.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Performance of an auto-adjusting prosthetic socket during walking with intermittent socket release. Weathersby, EJ., Vamos, AC., Larsen, BG., et al.[2022]

The newly developed device accurately measures socket/shank angular alignment in prostheses with a repeatability of 1 degree across a 20-degree range, enhancing precision in prosthetic fitting.

This device serves as a valuable tool for teaching and research in prosthetics, potentially improving the fitting process and outcomes for users.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

An angular alignment measurement device for prosthetic fitting. Sanders, JE., Daly, CH., Boone, DA., et al.[2022]

The prosthetic socket serves as a crucial customized interface between the residual limb and the prosthetic components, focusing on weight bearing, suspension, and stability during movement.

The article reviews the engineering designs of two primary types of below-the-knee prosthetic sockets, emphasizing the importance of maximizing load distribution and minimizing unwanted movements for optimal function.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Below knee prosthetic socket designs and suspension systems. Edwards, ML.[2013]

References

1. England pubmed.ncbi.nlm.nih.gov

Socket size adjustments in people with transtibial amputation: Effects on residual limb fluid volume and limb-socket distance. [2022]

2. England pubmed.ncbi.nlm.nih.gov

A motor-driven adjustable prosthetic socket operated using a mobile phone app: A technical note. [2019]

3. England pubmed.ncbi.nlm.nih.gov

Adjustable prosthetic sockets: a systematic review of industrial and research design characteristics and their justifications. [2023]

4. France pubmed.ncbi.nlm.nih.gov

A new in-built device for one-point stepless prosthetic alignment. [2017]

5. England pubmed.ncbi.nlm.nih.gov

Performance of an auto-adjusting prosthetic socket during walking with intermittent socket release. [2022]

6. France pubmed.ncbi.nlm.nih.gov

An angular alignment measurement device for prosthetic fitting. [2022]

7. United States pubmed.ncbi.nlm.nih.gov

Below knee prosthetic socket designs and suspension systems. [2013]