R21: An Easy-to-use, iNtelligent, Affordable LinEr (ENABLE) System for Socket Fit Assessment

NCT ID: NCT05425810

Last Updated: 2025-05-20

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 3 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2021-04-20
• Study Completion Date: 2026-02-27

Brief Summary

Lower limb amputees (LLA) rely on their prosthetic legs to remain active and lead an independent life. For most LLAs, a well-fitted prosthetic socket is the only option to interface with their prosthetic leg, however, it is a real challenge to make a prosthetic socket to interface with residual limbs accurately. One of the reasons is that there lack of accurate approaches to evaluate the pressure distribution on the residual limb accurately and effectively. To overcome this issue, the research team will develop an innovative sensing system, which permits the prosthetists to track the pressure distribution on the residual limb visually. The capability of the new sensing system will be demonstrated on lower limb amputees.

Detailed Description

A novel pressure sensing pad will be tested in the project. The purpose of these tests is to collect the safety and efficacy of the sensing pad. The research team would like to seek a Non-significant Risk claim from Institutional Review Board (IRB).

The pad will be made of materials similar to the normal liner with embedded nanotubes. The nanotubes are filled with gallium alloys, of which resistance will change based on loaded pressure. When constant current passes these tubes, the change of pressure leads to a change in temperatures around, which will excite thermal-sensitive dyes to change color. So the research team could estimate the pressure at a given area based on the color around it.

The experimental procedure includes three sets and requires 3-4 visits from each subject.

Set I procedure includes a standard socket construction, which requires 2-3 visits for the subjects to the office of a local prosthetic company. Then, a certified prosthetist will build a test socket and a customized liner to maximize the socket fit and comfort and conduct the needed alignment of the prosthetic leg. Unless it is necessary, all testing sockets will be duplications of amputees' everyday sockets.

Set II will test the accuracy of the constructed prototype on amputee subjects compared to a commercially available sensor pad, which serves as a reference. First, the research team will mount both sensing systems on the subjects. The reference sensor grid will be mounted on the residual limb directly using medical tape. After the subject dons the ENABLE sensing pad, the research team will register two sensing systems. In the end, the subjects are required to don the testing socket and walk continuously, so the measurement of the developed prototype could be stabilized. Pictures of the ENABLE will be taken and compared with the recorded pressure signals from the reference grid.

Although the reference grid and ENABLE system are designed to be put on easily, brief assistance from experimenters will be needed to ensure that the mounting procedure can be conducted appropriately.

Set III will test whether information from the ENABLE leads to appropriated socket-fit-assessments based on the response of experienced prosthetists when the prosthetists are shown the pressure distribution measured by the ENABLE under different fit conditions. All subjects will be exposed to five socket fit conditions: good and additional foam pads at four different areas shown in a random sequence. The size of the pad at each location is selected by the prosthetists based on the shape and size of the residual limbs.

Under each fitting condition, each subject will go through three trials. In each trial, the subject will walk continuously until the color of the sensing pad is stabilized. After taking high-resolution digital pictures, which cover most of the sensing area of the ENABLE, the research team will let the subject rest until the optical pattern of the ENABLE fades completely before starting a new trial.

After the experiments are finished, the subject will need to fill out a survey about the comfort of the ENABLE system. The survey will be conducted just after the experimental procedure on paper. During Set II and III, a fall prevention harness is available for the participants if it is needed. The participants are requested to self-monitor the pressure and thermal conditions on their residual limbs and encouraged to request the early termination of the experimental procedure.

Conditions

Lower Limb Amputation Below Knee (Injury)

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: DEVICE_FEASIBILITY
• Blinding Strategy: NONE

Study Groups

Transtibial patient

All the recruited participants will be included in this arm and will go through the socket manufacturing, fitting, and testing procedure.

Group Type: EXPERIMENTAL

Apply ENABLE sensing pad

Intervention Type: DEVICE

The developed ENABLE system is integrated into the standard prosthetic liner and measures the pressure distribution during locomotion. Using the ENABLE system may lead temporary increase in the temperature inside the prosthetic socket and it is expected that the total exposition during the experimental procedure will be less than 10 min.

Insert small pads at pressure tolerant locations

Intervention Type: DEVICE

To change the pressure distribution inside the socket, four fitting conditions are introduced by adding small pads at patella tendon (PT), lateral tibial crest (LTC), medial tibial crest (MTC), and popliteal fossa (PF) respectively. Including the no pads scenario, totally of five fitting conditions are simulated.

Interventions

Apply ENABLE sensing pad

The developed ENABLE system is integrated into the standard prosthetic liner and measures the pressure distribution during locomotion. Using the ENABLE system may lead temporary increase in the temperature inside the prosthetic socket and it is expected that the total exposition during the experimental procedure will be less than 10 min.

Intervention Type: DEVICE

Insert small pads at pressure tolerant locations

To change the pressure distribution inside the socket, four fitting conditions are introduced by adding small pads at patella tendon (PT), lateral tibial crest (LTC), medial tibial crest (MTC), and popliteal fossa (PF) respectively. Including the no pads scenario, totally of five fitting conditions are simulated.

Intervention Type: DEVICE

Eligibility Criteria

Inclusion Criteria

• Unilateral transtibial amputees
• At least 1 year of experience using his/her prosthetic leg
• Has used the current socket for at least 6 months without a significant skin issue or major modification
• Can comfortably walk 3 mins without pausing to rest
• The fibula length on the residual limb must be greater than half of the length of the fibula on the unaffected side

Exclusion Criteria

• Cognitive or visual impairment that affects the participant's ability to provide informed consent or to follow simple instructions during the experiments
• neuropathy observed on the residual limb
• regnant female

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 99 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

North Carolina State University

OTHER

Sponsor Role: lead

Responsible Party

Ming Liu

Research Assistant Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

NC State University

Raleigh, North Carolina, United States

Site Status: RECRUITING

Countries

United States

Central Contacts

Ming Liu, PhD

Role: CONTACT

mliu10@ncsu.edu

9195158541

He Huang, PhD

Role: CONTACT

hhuang11@ncsu.edu

9195158541

Facility Contacts

Ming Liu

Role: primary

mliu10@ncsu.edu

919-515-8541

He Huang

Role: backup

hhuang11@ncsu.edu

9195158541

Provided Documents

Document Type: Informed Consent Form

View Document

Other Identifiers

23949

Identifier Type: -

Identifier Source: org_study_id