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

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests a new prosthetic socket system that automatically adjusts to changes in leg size for individuals with below-knee amputations. The goal is to enhance comfort and reduce issues like pain or skin problems from poor fit. Participants will use the system in various settings, both in labs and daily life. Suitable candidates for this trial include those who have had a below-knee amputation for at least a year, regularly use a prosthesis, and have experienced changes in limb size. As an unphased trial, this study allows participants to contribute to innovative research that could improve prosthetic comfort and quality of life.

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 prior data suggests that this auto-adjusting prosthetic socket is safe for people with leg amputations?

Research has shown that auto-adjusting prosthetic sockets are generally well-received. These sockets adapt to fit the limb better as its size changes, enhancing comfort and helping to prevent pain and skin issues. Studies have found that these systems adjust automatically, eliminating the need for manual changes during the day.

Although specific safety data from clinical trials is not available here, the emphasis on comfort and fit suggests a design prioritizing user safety. For those considering participation in a trial for an auto-adjusting prosthetic socket, the evidence so far indicates a positive safety profile. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about the auto-adjusting prosthetic socket because it offers a new level of comfort and adaptability for individuals with below-knee amputations. Unlike traditional prosthetic sockets, which require manual adjustments and can be uncomfortable over time, this smart prosthesis uses an auto-adjusting algorithm to adapt in real-time to the user's movements and environment. Additionally, a key-fob device allows users to control the socket system easily, enhancing convenience and user control. This innovative approach could significantly improve the daily lives of amputees by providing a more personalized fit and reducing the need for frequent adjustments.

What evidence suggests that the Auto Adjusting Prosthesis is effective for people with leg amputations?

Research has shown that a self-adjusting prosthetic socket can increase satisfaction and improve limb health for people with leg amputations. For those with reduced limb sensation, it may also help prevent falls. This trial will evaluate the auto-adjusting prosthetic socket in various settings. In the In-Lab Crossover Study arm, participants will test the auto-adjusting algorithm in a controlled environment. Meanwhile, the Out-of-Lab Crossover Study arm will assess socket performance in real-world settings. Studies have found that these sockets can automatically adjust during activities like walking, enhancing fit and comfort throughout the day. A review of these adjustable socket designs suggests they can better accommodate changes in limb size, leading to a more comfortable experience. Overall, this new approach aims to address common issues like pain and skin problems by ensuring the socket consistently fits well. ^{1 6 7 8 9}

Who Is on the Research Team?

Joan E Sanders, PhD

Principal Investigator

University of Washington

Are You a Good Fit for This Trial?

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 for a Trial Participant

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

What Are the Treatments Tested in This Trial?

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.

How Is the Trial Designed?

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+

Published Research Related to This Trial

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 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]

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]

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]

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]

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]

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]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC9087223/

Performance of an auto-adjusting prosthetic socket during ... An auto-adjusting socket may improve satisfaction and limb health and reduce the risk of a fall, particularly for people with poor limb sensation who have ...

2. nature.com nature.com/articles/s41598-024-61234-9

An adaptive prosthetic socket for people with transtibial ... This study presents results from take-home testing of a motor-driven adaptive socket that automatically adjusted socket size during walking.

3. clinicaltrials.gov clinicaltrials.gov/study/NCT05124652

An Automatically Adjusting Prosthetic Socket for People ... 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 ...

4. jneuroengrehab.biomedcentral.com jneuroengrehab.biomedcentral.com/articles/10.1186/s12984-023-01270-0

Adjustable prosthetic sockets: a systematic review of industrial ... This paper reviews adjustable socket designs, as they have the potential to improve prosthetic fit and comfort through accommodating residual limb volume ...

5. rehab.jmir.org rehab.jmir.org/2025/1/e69962

Evidence-Generated Sockets for Transtibial Prosthetic Limbs ... Conclusions: EG sockets demonstrated noninferiority to conventional clinical CASD practice in terms of socket comfort. Both quantitative and ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10626671/

Adjustable prosthetic sockets: a systematic review of industrial ... This paper reviews adjustable socket designs, as they have the potential to improve prosthetic fit and comfort through accommodating residual limb volume ...

7. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC8825909/

Developing a control framework for self-adjusting prosthetic ... This paper presents a framework for automatic control of an adjustable transtibial prosthetic socket that enables active adaptation of residuum-socket ...

8. tandfonline.com tandfonline.com/doi/full/10.1080/19498241.2024.2420595

ADJUSTABLE-VOLUME PROSTHETIC INTERFACES The purpose of this article is to identify, critically appraise, synthesize, and to perform a meta-analysis of the available evidence pertaining to adjustable- ...

9. researchgate.net researchgate.net/publication/360601894_Performance_of_an_auto-adjusting_prosthetic_socket_during_walking_with_intermittent_socket_release

(PDF) Performance of an auto-adjusting prosthetic socket ... Introduction: A challenge in the engineering of auto-adjusting prosthetic sockets is to maintain stable operation of the control system while ...