Automatic Prosthetic Foot Stiffness Modulation to Improve Balance in the Real World

NCT07791433 | Not Yet Recruiting FDA Device

• 2 other identifiers: 1817327-271R01HD111514-01A1
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to determine if automatic stiffness modulation improves balance control in ambulatory individuals with below-knee amputations in real-world conditions. The main question this clinical trial will answer is: • Can a user-specific automatic stiffness prosthesis improve balance control compared to user's fixed stiffness prosthesis that was clinically prescribed? Participants will perform free-ranging ambulatory activities outside the laboratory that include nine ambulatory activities of daily living (walking at different speeds, turning, ramp ascent/descent, while carrying a load, and while walking on uneven terrain) while wearing, in random order, 1) a fixed stiffness prosthesis that was clinically prescribed and 2) an automatic stiffness prosthesis that uses an open source ankle configured to implement a user- and activity-specific automatic stiffness modulation control scheme intended to improve balance control.

Conditions

Lower Limb Amputation Below Knee

Keywords

lower limb prosthesis; transtibial amputation; below knee amputation; biomechanics; gait

Outcome Measures

Primary Outcomes (1)

• Peak-to-peak range of the frontal plane whole-body angular momentum

  Frontal plane whole-body angular momentum is a measure of the extent to which a person will rotate in the frontal plane in the absence of an external force or torque. The peak-to-peak range quantifies how much this metric varies and is used to describe a person's balance.

  During study visit (approximately 3 hours)

Secondary Outcomes (2)

• Prosthetic Limb Users Survey of Mobility

  During study visit (approximately 3 hours)

• Activities-Specific Balance Confidence Scale

  During study visit (approximately 3 hours)

Study Arms (2)

Fixed stiffness prosthesis then automatic stiffness prosthesis

EXPERIMENTAL

A within-subject crossover experiment will be conducted to determine if differences in balance control (peak-to-peak range of frontal plane whole body angular momentum) exist between two study prostheses. The two study prostheses include (1) the participant's fixed stiffness prosthesis and (2) a novel, automatic stiffness prosthesis. The order in which participants wore the study prostheses was randomized. The study will be conducted over 2 weeks. All participants will walk a defined course (both indoors and outdoors) about a hospital facility. Participants in this group will wear their fixed stiffness prosthesis first and then the automatic stiffness prosthesis.

Device: Fixed stiffness prosthesis; Device: Automatic stiffness prosthesis

Automatic stiffness prosthesis then fixed stiffness prosthesis

EXPERIMENTAL

A within-subject crossover experiment will be conducted to determine if differences in balance control (peak-to-peak range of frontal plane whole body angular momentum) exist between two study prostheses. The two study prostheses include (1) the participant's fixed stiffness prosthesis and (2) a novel, automatic stiffness prosthesis. The order in which participants wore the study prostheses was randomized. The study will be conducted over 2 weeks. All participants will walk a defined course (both indoors and outdoors) about a hospital facility. Participants in this group will wear the automatic stiffness prosthesis and then their fixed stiffness prosthesis.

Device: Fixed stiffness prosthesis; Device: Automatic stiffness prosthesis

Interventions

Fixed stiffness prosthesis DEVICE

The participant's clinically prescribed prosthesis whose stiffness category is determined by the person's body weight and activity level (standard clinical practice).

Automatic stiffness prosthesis then fixed stiffness prosthesis; Fixed stiffness prosthesis then automatic stiffness prosthesis

Automatic stiffness prosthesis DEVICE

A novel prosthesis whose user-specific and activity-specific stiffness profile is automatically modulated based on their ambulatory activity.

Automatic stiffness prosthesis then fixed stiffness prosthesis; Fixed stiffness prosthesis then automatic stiffness prosthesis

Eligibility Criteria

• Age: 18 Years - 79 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Unilateral transtibial (below-knee) amputation
• Been fit with a prosthesis and used it for at least 6 months
• Wear the prosthesis for 4 or more hours on average per day
• Be at least one-year post-amputation
• Able to walk on a treadmill

You may not qualify if:

• Presence of disorder, pain, or injury other than amputation that interferes with gait
• Current skin irritation or injury on residual limb
• Use of an assistive device for walking (cane, walker, etc.)

Sponsors & Collaborators

• Seattle Institute for Biomedical and Clinical Research: lead
• Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD): collaborator

Study Sites (1)

VA Puget Sound Healthcare System

Seattle, Washington, 98108, United States

Location

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 10, 2026
• First Posted: August 28, 2026
• Study Start (Estimated): November 1, 2026
• Primary Completion (Estimated): November 1, 2027
• Study Completion (Estimated): November 1, 2028
• Last Updated: August 28, 2026

Record last verified: 2026-08

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, ICF
• Time Frame: Publication-associated datasets will be submitted to Data and Specimen Hub at least 4 months prior to publication so that data can be shared on or before the initial publication date. The full study dataset will be submitted to Data and Specimen Hub at least 6 months prior to the end of the award period. The Data and Specimen Hub do not currently have any data deprecation or sunsetting protocols, allowing shared data to be preserved for the foreseeable future.
• Access Criteria: The Data and Specimen Hub are a National Institutes of Health controlled-access data repository. The Eunice Kennedy Shriver National Institute of Child Health and Human Development Data and Specimen Hub Data Access Committee reviews all requests to access Data and Specimen Hub data from identity-verified requesters to determine whether the proposed use is scientifically and ethically appropriate and does not conflict with constraints or research data use limitations identified by the institutions that submitted the research data. The Recipient's institution and the Recipient must sign and agree to the terms and conditions in the N Eunice Kennedy Shriver National Institute of Child Health and Human Development Data and Specimen Hub Data Use Agreement for accessing research data.

Locations

US (1)