AMI Construction in Lower Extremity Residual Limbs

A Novel Approach to Lower Extremity Residual Limb Revision to Augment Volitional Motor Control, Restore Proprioception and Reverse Limb Atrophy

This study will involve the development of a novel approach to lower extremity residual limb surgical revision that offers the promise of augmenting volitional motor control, restore proprioception and reverse atrophy

Study Overview

• Status: Recruiting
• Conditions: Amputation
• Intervention / Treatment: Procedure: Residual limb revision

Detailed Description

The hypothesis of this research protocol is that we will be able to modify the residual limbs of patients who have already undergone lower extremity amputations so as to include biological actuators that will enable the successful employment of next generation lower extremity prostheses, diminish/eliminate phantom limb pain, restore proprioception and regenerate lost muscle mass. The specific aims of the project are as follows:

1. To develop a standardized operative technique for both above knee (AK) and below knee (BK) amputation revision procedures that includes AMIs to restore musculotendinous proprioceptive capabilities
2. To assess the capacity for these actuators to provide enhanced motor control and sensory feedback, as well as ablate phantom limb symptomatology and augment residual limb muscle mass
3. To determine the reinnervation time course and longevity of these biological constructs
4. To validate the functional and somatosensory superiority of the proposed revision technique over standard approaches to BKA and AKA
5. To develop a modified acute postoperative rehabilitation strategy suited to this new surgical approach

• Study Type: Interventional
• Enrollment (Estimated): 26
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Matthew J Carty, MD; Phone Number: 6179834555; Email: mcarty@partners.org
• Study Contact Backup: Name: Research Coordinators; Email: limbrestoration@bwh.harvard.edu

Study Locations

• United States
  • Maryland
    • Bethesda, Maryland, United States, 20889
      • Not yet recruiting
      • Walter Reed National Military Medical Center
      • Contact: Kyle Potter, MD; Email: benjamin.k.potter.mil@mail.mil
  • Massachusetts
    • Boston, Massachusetts, United States, 02115
      • Recruiting
      • Brigham and Women's Hospital
      • Contact: Matthew J Carty, MD; Phone Number: 617-983-4555; Email: mcarty@partners.org
    • Cambridge, Massachusetts, United States, 02139
      • Recruiting
      • Massachusetts Institute of Technology
      • Contact: Hugh Herr, PhD; Phone Number: 617-314-3661; Email: hherr@media.mit.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Between the ages of 18-65
• Has already undergone a standard AKA or BKA procedure

• Suffers from symptoms such as:

  • Intractable pain
  • Deterioration of skin on or around stump
  • Suffering from other sources of discomfort arising from stump
• Intact inherent wound healing
• Adequate communication skills
• High motivation

Exclusion Criteria:

• Inadequate health to undergo operative procedure using standard anesthesia (i.e. cardiopulmonary)
• Individuals with impaired wound healing
• Individuals suffering from extensive peripheral neuropathies
• Active smokers
• Individuals with a history of poor compliance
• Women who are pregnant or plan to become pregnant before surgical intervention

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intervention; Subjects undergoing the proposed operative intervention. Intervention patients will serve as their own control for all outcome measures	Procedure: Residual limb revision; Surgical procedure involving construction of agonist-antagonist myoneural interfaces (AMIs)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Limb Morphology and Changes in Muscle Volume	Clinical examination and images from CT/MRI will be combined to construct a holistic view of the morphology of the residual limb. Imaging studies and limb measurements taken in clinic will also be used to measure muscle atrophy/hypertrophy over time.	Years 1-3
Degree of Motor Activation of AMI Muscles and Volitional Control of Phantom Limb	Clinical examination will confirm the sliding motion of the AMI constructs with radiologic evaluation measuring the length of muscle excursion through each construct. Functional testing and testing using a prosthesis will determine how well a patient is able to volitionally control the AMI muscles.	Years 1-3
Evidence of Proprioception	Subjective reporting combined with tests run using a prosthesis will indicate if proprioception is still intact after surgery. Results will be confirmed by monitoring brain activity during limb movement activities via fMRI.	Years 1-3
Evidence of Sensory Perception	Subjective reporting and clinical tests of Semmes-Weinstein and two-point discrimination will determine if the patient has sensory perception on the residual limb.	Years 1-3
General Health	Patient-reported outcomes metrics from five validated tests (SIP136, EQ-5D, SF-36, LEFS, PROMIS) will be combined to create an overall picture of patients' general health during and after their recovery.	Years 1-3
Complications	Delayed wound healing, infection, need for additional surgery, PE/DVT, death	Years 1-3

Collaborators and Investigators

• Sponsor: Brigham and Women's Hospital
• Collaborators: United States Department of Defense; Massachusetts Institute of Technology; Walter Reed National Military Medical Center
• Investigators: Principal Investigator: Matthew J Carty, MD, Brigham and Women's Hospital

Study record dates

Study Major Dates

• Study Start (Actual): February 24, 2020
• Primary Completion (Estimated): September 30, 2026
• Study Completion (Estimated): September 30, 2026

Study Registration Dates

• First Submitted: June 15, 2019
• First Submitted That Met QC Criteria: August 16, 2019
• First Posted (Actual): August 21, 2019

Study Record Updates

• Last Update Posted (Actual): October 20, 2025
• Last Update Submitted That Met QC Criteria: October 15, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: Amputation; Residual limb pain; Phantom pain; Prosthesis control; Residual limb atrophy
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Nervous System Diseases; Postoperative Complications; Pathologic Processes; Neurobehavioral Manifestations; Perceptual Disorders; Pain, Postoperative; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Phantom Limb
• Other Study ID Numbers: 2019P001681; CDMRP-180114 (Other Grant/Funding Number: Department of Defense)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be available to other researchers

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No