An Osseointegrated Transfemoral Prosthesis Offering Long-Term Bi-Directional Efferent-Afferent Neural Transmission

An Osseointegrated Transfemoral Prosthesis Offering Long-Term Bi-Directional Efferent-Afferent Neural Transmission - IDE Required

The purpose of the study is to investigate the clinical and functional outcomes of a transfemoral amputation with osseointegrated titanium implant, AMI muscle constructs, and implanted electrodes in the domain of gait, free space control, and embodiment.

Study Overview

• Status: Active, not recruiting
• Conditions: Transfemoral Amputation
• Intervention / Treatment: Device: MIT Powered Knee Prosthesis

• Study Type: Interventional
• Enrollment (Actual): 2
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Massachusetts
    • Cambridge, Massachusetts, United States, 02139
      • MIT Media Lab

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• 1 Male or Female age 22-65 at the time of surgery.
• 2 The patient must have a medical condition requiring performance of a unilateral transfemoral amputation with a minimum of 13 cm of residual femur after amputation, and: A. At a minimum level of amputation of 20 cm or greater above the knee joint line if physical therapy and prosthetist evaluation is commensurate with a standard K3 ambulatory status; or, B. At a minimum level of amputation of 16 cm above the knee joint line as part of a single- stage procedure if physical therapy and prosthetist evaluation is commensurate with a more active K3 or less active K4 postoperative ambulatory status.
• The subject must have undergone independent consultation with at least two lower extremity surgical specialists 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.
• The patient must have the ability to ambulate at variable cadence (an expected lower extremity prosthesis functional level of K3 or above).
• The patient must have adequate bone stock to support the implanted device.
• In the opinion of the investigators, normal cognitive function and absence of any physical limitations, addictive diseases or underlying medical conditions that may preclude patient from being a good surgical and/or study candidate.
• Willingness, ability and commitment to participate in baseline and follow-up evaluations for the full length of the study including the prescribed rehabilitation program.
• Written informed consent to participate in the study provided by the patient or legal representative.

Exclusion Criteria:

• Women who are pregnant, lactating or planning a pregnancy during the first twelve (12) months of the post-surgical follow- up.
• Subjects who have not been completely abstinent from tobacco use for at least 6 weeks preoperatively.
• Active infection or dormant bacteria.
• Subjects would have less than 2 mm of remaining cortex bone available around the implant, if implanted.
• 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 subject to be a good study candidate.
• Evidence of any active skin disease involving the proposed surgical limb.
• History of systemically administered corticosteroids, immune- suppressive therapy or chemotherapy drugs within six (6) months of implant surgery.
• Severe co morbidity, atypical skeletal anatomy, or poor general physical/mental health that, in the opinion of the Investigator, will not allow the subject to be a good study candidate (i.e. other disease processes, mental capacity, substance abuse, shortened life expectancy, vulnerable patient population, BMI >40, etc.).
• The patient is currently involved in another clinical study where that participation may conflict or interfere with the treatment, follow-up or results of this clinical study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• 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: Osseointegration surgery; Transfemoral amputation with osseointegrated titanium implant, AMI muscle constructs, and implanted electrodes	Device: MIT Powered Knee Prosthesis; MIT powered knee prosthesis developed by the MIT Biomechatronics Group.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Kinematic Measures of Lower-Limb Biomechanics	Quantitative analysis of joint angles, during level-ground walking, stair negotiation, and other functional tasks. Outcomes will be assessed using a motion capture system (e.g., Vicon) and embedded prosthesis sensors.	An average of 2 sessions in the span of 1 week
Spatiotemporal Gait Parameters	Evaluation of stance-to-swing ratio during ambulation. Parameters will be obtained using a motion capture system (e.g., Vicon) and an instrumented walkway. Data will be analyzed to assess functional walking ability and compared to normative or baseline values.	An average of 2 sessions in the span of 1 week
Assessment of Patient Ability to Control each Joint of the Prosthesis	Assessment of volitional control of the powered knee and ankle joints via neural signals from the residual limb. Participants will perform isolated joint control trials in seated positions. Outcomes include joint command accuracy evaluated using surface electromyography (EMG) and motion capture. These measures will quantify the participant's ability to intentionally control each prosthetic joint.	An average of 2 sessions in the span of 1 week
Ground Reaction Forces	Quantitative analysis of ground reaction forces during level-ground walking, stair negotiation, and other functional tasks. Outcomes will be assessed using instrumented force plates.	An average of 2 sessions in the span of 1 week
Joint Torques	Quantitative analysis of joint torques during level-ground walking, stair negotiation, and other functional tasks. Outcomes will be assessed using a motion capture system (e.g., Vicon), instrumented force plates, and embedded prosthesis sensors.	An average of 2 sessions in the span of 1 week
Walking speed	Evaluation of walking speed during ambulation. Parameters will be obtained using a motion capture system (e.g., Vicon) and an instrumented walkway. Data will be analyzed to assess functional walking ability and compared to normative or baseline values.	An average of 2 sessions in the span of 1 week

Collaborators and Investigators

• Sponsor: Massachusetts Institute of Technology
• Collaborators: Integrum
• Investigators: Principal Investigator: Hugh Herr, PhD, Massachusetts Institute of Technology

Study record dates

Study Major Dates

• Study Start (Actual): April 15, 2017
• Primary Completion (Actual): July 18, 2025
• Study Completion (Estimated): July 17, 2026

Study Registration Dates

• First Submitted: October 10, 2025
• First Submitted That Met QC Criteria: May 22, 2026
• First Posted (Actual): May 29, 2026

Study Record Updates

• Last Update Posted (Actual): May 29, 2026
• Last Update Submitted That Met QC Criteria: May 22, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: 1703900740

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data (IPD) will not be shared. This study involves a small cohort and a particular surgical procedure. Even with direct identifiers removed, the combination of clinical timelines and outcomes could increase the risk of re-identification. Summary/aggregate results (and selected analyses) have been reported in a peer-reviewed publication.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes