Feasibility Study Evaluating the Safety and Effectiveness of Magnetic Bead Tracking System When Used With a Bionic External Prosthesis

NCT07195461 | Recruiting Early Phase 1 DMC FDA Device

• 1 other identifier: 2025P001485
• Study Type: interventional
• Target: 3
• Locations: 1 country
• Sites: 1

Brief Summary

The investigation is an early feasibility study in up to 5 subjects, in which the primary objective is to capture preliminary safety and effectiveness information on the Magnetic Bead Tracking system.

Conditions

Transtibial Amputee; Transtibial Amputation

Keywords

transtibial; amputation; amputee; magnet; prosthesis

Outcome Measures

Primary Outcomes (2)

• Walking Speed

  The preferred and fastest walking speeds across level-ground and uneven walking surfaces will be measured as the primary study variables for AIM 1. To make these measurements, the time duration will be measured for each study subject to walk at steady state speed overground across 10m walkways at their preferred and fastest walking speeds. Subjects will receive standardized instructions encouraging them to either walk at their comfortable walking speed, or at their maximum walking speed, across each level-ground andan uneven 10m walkway. The investigators expect that the preferred and maximum speeds will be higher when employing the magnetomicrometry (MM) prosthetic controller compared to the commercial intrinsic controller, in support of the H1 hypothesis.

  One timepoint, between days 150-180.

• Obstacle course speed

  The time to traverse an obstacle course will be evaluated to test obstacle avoidance, changes in walking direction, slope/stair variations, and speed transients, testing the ability of each controller to deliver rapid gait maneuvers while subjects walk across the unstructured environment. The investigators expect that the time to complete the obstacle course will be lower when employing the MM controller compared to the commercial intrinsic controller, further supporting the H1 hypothesis.

  One timepoint, between days 150-180.

Secondary Outcomes (9)

• Walking Distance

  One timepoint, between days 150-180.

• Gait Symmetry

  One timepoint, between days 150-180.

• Biologic Realism

  One timepoint, between days 150-180.

• Musculoskeletal Stress

  One timepoint, between days 150-180.

• Stability (1)

  One timepoint, between days 150-180.

Study Arms (1)

Transtibial amputees

EXPERIMENTAL

Up to five subjects signing an informed consent and meeting all inclusion and exclusion criteria will be enrolled into the study to receive the Magnetic Bead Tracking System. Each subject will serve as their own control in a repeated measures ('within subjects') design. During experimentation, each subject will have prosthetic gait performance measured while using the Magnetic Bead Tracking System compared to an intrinsic robotic controller.

Device: Magnetic Bead Tracking System

Interventions

Magnetic Bead Tracking System DEVICE

The Magnetic Beads will be implanted in a subject during either an already required revision of an existing unilateral or bilateral transtibial amputation or during the performance of a unilateral or bilateral transtibial amputation.

Transtibial amputees

Eligibility Criteria

• Age: 22 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Male or Female age 22-65 at the time of surgery.
• The patient must already have an existing unilateral or bilateral transtibial amputation requiring revision or a medical condition requiring performance of a unilateral or bilateral transtibial amputation.
• If the patient does not already have an amputation, the patient must have undergone independent consultation with a lower extremity surgical specialist to ensure they have exhausted all limb salvage options prior to undergoing amputation, as well as a psychiatric evaluation to ensure appropriate capacity and volition, and a pain medicine evaluation to ensure that all pain control options outside of amputation have been addressed.
• The patient must have the ability to ambulate at variable cadence (an expected lower extremity prosthesis functional level of K3 or above, as determined by a trained and certified prosthetist and confirmed by study investigators, through use of a patient history and physical examination).
• The patient must have adequate soft tissue bulk and muscle mass present in the operative limb to support appropriate wound healing.
• The patient must demonstrate volitional activation of the muscles into which magnet placement is intended.
• In the opinion of the investigator, the patient must likely be able to tolerate the pressure of a prosthetic socket during ambulation post-operatively.
• In the opinion of the investigator, the patient must have absence of any physical limitations, addictive diseases or underlying medical conditions that may preclude the patient from being a good study candidate.
• The patient must have willingness, ability and commitment to participate in baseline and follow-up evaluations for the full length of the study.
• The patient must have willingness and ability to provide informed consent to participate in the study.

You may not qualify if:

• Patients with any active skin disease in the subject limb.
• Patients with severe comorbidity, atypical skeletal anatomy, or poor general physical/mental health that, in the opinion of the Investigator, will not allow the patients to be a good study candidate (i.e., other disease processes, mental capacity, substance abuse, shortened life. expectancy, vulnerable patient population, etc.).
• Patients with the following concurrent diseases: active infection or dormant bacteria, metabolic bone disease and/or metastatic lesions in the residual tibia.
• Patients weighing over 285 lbs. with the prosthesis, at time of screening.
• Patients for whom skeletal growth is not complete. Completed skeletal growth is defined through the finding of generally closed epiphyseal zones on X-ray.
• Patients with advanced atrophic muscle and/or compromised soft tissue coverage in the operative limb.
• Patients with evidence of or a documented history of severe peripheral vascular disease, diabetes mellitus (type I or type II), skin diseases, neuropathy or neuropathic disease and severe phantom pain, or osteoporosis, such that, in the opinion of the investigator, will not allow the patient to be a good study candidate.
• Patient with a history of systemically administered corticosteroids, immune-suppressive therapy or chemotherapy drugs within six (6) months of implant surgery.
• Patients with a known need of future MRIs.
• Patients currently involved in another clinical study where that participation may conflict or interfere with the treatment, follow-up or results of this clinical study.
• Active smokers will be excluded from candidacy; those patients willing to undergo tobacco cessation will need to be completely abstinent from tobacco use for at least 6 weeks preoperatively.
• Women who are pregnant, lactating or planning a pregnancy during the first twelve (12) months of the post-surgical follow-up.
• Patient having an allergy to any component of the device.
• Patients with concurrent illness, disability or geographical residence that would hamper attendance at required study visits.

Sponsors & Collaborators

• MuscleMetrix, LLC: lead

Study Sites (1)

Brigham and Women's Hospital

Boston, Massachusetts, 02115, United States

RECRUITING

Study Officials

• Matthew J. Carty, M.D.

  Brigham and Women's Hospital

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Deborah Grayeski, JD

CONTACT

202-550-7395; deborah.grayeski@gmail.com

Kendall Program Manager

CONTACT

kclites@mgb.org

Study Design

• Study Type: interventional
• Phase: early phase 1
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: September 11, 2025
• First Posted: September 26, 2025
• Study Start: September 11, 2025
• Primary Completion: April 1, 2026
• Study Completion: April 1, 2026
• Last Updated: September 26, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will share

Locations

US (1)