AmputationTTeOPRA+MBNCT06391697
Magnetic Bead Tracking System and eOPRA Implant System With Bionic Prosthesis for Transtibial Amputees
A study testing eOPRA Implant System for Transtibial Amputees and Magnetic Bead Tracking System in people with Amputation, run by Brigham and Women's Hospital at 2 sites in United States.
Trial summary
The e-OPRA Implant System, is a further development of the OPRA (Osseointegrated Prostheses for the Rehabilitation of Amputees) Implant System. The e-OPRA Implant system is an implant system for direct skeletal anchorage of amputation prostheses. Read more about this study
- Who is it for?
- Ages 22 to 65 years
- Conditions the study is for
- Amputation
- What is being tested?
- eOPRA Implant System for Transtibial Amputees and Magnetic Bead Tracking System
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 7 participants
- Where
- 2 sitesUnited States
- Study dates
- 1 May 2024to 2 May 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 22 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Male or Female age 22-65 at the time of surgery.
- The subject must already have been implanted with the e-OPRA Implant System at the transtibial level or must have an existing unilateral or bilateral transtibial amputation or a medical condition requiring performance of a unilateral or bilateral transtibial amputation with a minimum of 8 cm of residual tibia after amputation, such that the subject will be implanted with the e-OPRA Implant System. (OPTION 1)
- If the subject does not already have the e-OPRA Implant System, 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. (OPTION 2)
- The patient must have the ability to ambulate at variable cadence (an expected lower extremity prosthesis functional level of K3 or above, as confirmed by study investigators).
- The patient must have adequate soft tissue bulk and muscle mass present in the operative limb to support appropriate wound healing.
- In the opinion of the investigator, normal cognitive function and absence of any physical limitations, addictive diseases or underlying medical conditions that may preclude the patient from being a good study candidate.
- Willingness, ability and commitment to participate in baseline and follow-up evaluations for the full length of the study.
- Willingness and ability to provide informed consent to participate in the study.
Who cannot join
- Subjects with any active skin disease in the tested limb.
- Subjects with 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.).
- For subjects who have not yet been implanted with the e-OPRA Implant System, subjects who would have less than 2 mm of remaining cortex bone available around the implant, if implanted.
- Subjects with advanced atrophic muscle and/or compromised soft tissue coverage in the operative limb.
- Subjects 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 subject to be a good study candidate.
- Subjects with a history of systemically administered corticosteroids, immune-suppressive therapy or chemotherapy drugs within six (6) months of implant surgery.
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- Subjects with a known need of future MRIs.
- Subjects 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.
- Subject has an allergy to any component of the device.
- Concurrent illness, disability or geographical residence would hamper attendance at required study visits.
Trial locations and contacts
2 sites in 1 country.
United States2 sites
Brigham and Women's Hospital
Boston, Massachusetts, 02115
MIT Media Lab
Cambridge, Massachusetts, 02139
About this study
Official title: A Feasibility Study Evaluating the Magnetic Bead Tracking System and Its Safety and Efficacy When Used With the e-OPRA Implant System and a Bionic External Prosthesis to Improve Prosthetic Controllability for Persons With Transtibial Amputation
The e-OPRA Implant System, is a further development of the OPRA (Osseointegrated Prostheses for the Rehabilitation of Amputees) Implant System. The e-OPRA Implant system is an implant system for direct skeletal anchorage of amputation prostheses. The added feature in the e-OPRA Implant system, is a bidirectional interface into the human body that allows permanent and reliable communication using implanted electrodes. These electrodes will provide long-term stable bioelectric signals for an improved control of the prosthetic limb. The Magnetic Bead Tracking System, which will be implanted and used in combination with the e-OPRA Implant system, is an investigational device that consists of pairs of magnetic beads, and a set of magnetic field sensors that measure and track the length of muscles and the speed at which they move in real-time. When the beads are implanted in muscle in the residual limb of an amputee, the muscle length signal is communicated to an investigational, robotic ankle-foot prosthesis. The purpose of the study is to evaluate the feasibility of a transtibial amputee with the e-OPRA Implant System and Magnetic Bead Tracking System exhibiting full neural control over a neuro-mechanical prosthetic system.
A maximum of seven subjects will be enrolled. Each subject will undergo one or more surgeries where the e-OPRA Implant System and Magnetic Bead Tracking System will be implanted. The subjects will participate in follow-up sessions the last of which occurs approximately 24 months after the surgery. This is a prospective, non-randomized, uncontrolled study.
Read the detailed description
Normalization of function for individuals with limb amputation is within reach, and will be achieved by smart implants capable of bi-directional communication between brain and machine via bone-anchored, interactive, powered prosthetic components. Rehabilitation of patients with expected high physical activity level, such as after amputation due to trauma or cancer, is currently limited by dependence on an external socket for the mechanical attachment of the prosthesis to the residuum. Despite the use of advanced materials and fabrication methods, socket interfaces routinely cause sores, chafing, pain, increased energy expenditure, and a decreased quality of life. Novel surgical techniques using osseointegrated transdermal titanium implants, now validated in Europe for over 25 years, obviate the need for painful sockets by establishing a direct, load-bearing link between skeleton and prosthesis. This system also promises a transformative breakthrough in neuroprosthetics, because it allows for fully internal, high bandwidth, stable neural connections. In a paper recently published in Science Translational Medicine, implanted muscle and nerve cuff electrodes were added to the osseointegrated device, creating a bi- directional efferent-afferent interface utilizing a safe and immune-sealed osseo-conduit. Commenting on this work, the editor stated, "Osseointegration could revolutionize the field of neuroprosthetics, giving patients more intuitive control and more freedom of movement."
Investigators have sought to advance bionic prostheses with sufficient degrees of freedom for performing natural tasks, such as manipulating objects in the case of upper-extremity prostheses, or walking and running for lower-extremity systems. Nonetheless, afferent feedback has not played a major role in any clinically-viable amputation prostheses, despite being critical for biomimetic control. This deficiency can, in large part, be attributed to a lack of clinically-available methodologies for sustained communication with the peripheral nervous system. There is no existing platform capable of invasive, robust, and permanent communication with the peripheral nervous system in a high-demand clinical set- ting. Only by bringing together critical technologies and expertise will it be possible to create a bionic limb replacement system with adequate suspension, load transmission, motor control, proprioceptive feedback, and external mechatronics that resemble the mass, volume and dynamics of the missing biological limb.
To develop the most advanced clinically- viable artificial limb and achieve the next level of prosthetic technology integration, a multi-disciplinary scientific team has been assembled with members from Massachusetts Institute of Technology (MIT: Carty, Herr, Brånemark) and Brigham and Women's Hospital (BWH: Carty, Ferrone). With proprioceptive afferent feedback, we seek to demonstrate that a person with transtibial amputation can exhibit full volitional control over a neuro-mechanical prosthetic system where key walking metrics are normalized, including preferred speed, metabolism and joint dynamics. It is the view of the proposers that the scope of this research is fundamental wherein the results will be shared broadly within the scientific community.
- Conditions
- Amputation
- Being tested
- eOPRA Implant System for Transtibial Amputees and Magnetic Bead Tracking System
- Keywords
- prosthesis, osseointegration, neural transmission, magnetic beads
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
eOPRA Implant System for Transtibial Amputees and Magnetic Bead Tracking SystemDevice
Also called eOPRA, e-Osseointegrated Prosthesis for the Rehabilitation of Amputees
The Magnetic Bead Tracking System is an investigational device that consists of pairs of magnetic beads, and a set of magnetic field sensors that measure and track the length of muscles and the speed at which they move in real-time. When the beads are implanted in muscle in the residual limb of an amputee, the muscle length signal is communicated to an investigational, robotic ankle-foot prosthesis.
The e-OPRA is an investigational implant system that lets a lower leg prosthesis attach securely to the remaining tibia bone. The e-OPRA device has been designed so that it can be implanted with an electrode set that consists of an electrical connector and electrodes to allow it to be used with both a neuro-mechanical (powered) prosthesis system, in addition to the standard prosthesis.
The operation to implant these devices will represent a modification of the surgical technique currently employed for standard below knee amputation.
| Study group | Role | What they receive |
|---|---|---|
| eOPRA Implant System for Transtibial Amputees and Magnetic Bead Tracking System | Experimental | Implantation of e-OPRA Implant System and Magnetic Bead Tracking System in lower limb. Receives: Device: eOPRA Implant System for Transtibial Amputees and Magnetic Bead Tracking System |
What is being measured
The primary outcome is the main question the study is designed to answer.
number of participants out of total who undergo device implantation (aim: 7 participants) who can complete robotics testing activities
testing activities include subject stability assessments, free space control activities using EMG, bead migration assessments, walking gait assessments and single-leg balance assessments
Measured: 3 - 24 months postop for all study participants
number of participants out of total who undergo device implantation (aim: 7 participants) who still have device successfully implanted at 24 months postop
successful implantation at 24 months is defined as having both eOPRA Implant System and Magnetic Beads Tracking System intact with no plans for removal due to device-related safety concern
Measured: 24 months postop for all study participants
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Apr 2024
- Study start1 May 2024
- Primary completion2 Sep 2026 (estimated)
- Study completion2 May 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for AmputationStudies of the same condition, open and under way.
- More trials run by Brigham and Women's HospitalThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Device feasibility
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 7 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Brigham and Women's Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- Massachusetts Institute of Technology, Integrum
- Responsible party
- Principal investigator, Matthew Carty, Brigham and Women's Hospital
- Investigators
- Matthew J Carty, MD, Principal investigator, Brigham and Women's HospitalHugh Herr, PhD, Principal investigator, Massachusetts Institute of Technology
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06391697
- Sponsor's protocol ID
- 2024P00006
- Acronym
- TTeOPRA+MB
- Status last verified
- Jul 2026
- First submitted
- 23 Apr 2024
- Last updated
- 9 Jul 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 9 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Feasibility Study Evaluating the Magnetic Bead Tracking System and Its Safety and Efficacy When Used With the e-OPRA Implant System and a Bionic External Prosthesis to Improve Prosthetic Controllability for Persons With Transtibial Amputation
- ClinicalTrials.gov ID
- NCT06391697
- Acronym / sponsor ID
- TTeOPRA+MB / 2024P00006
- Conditions
- Amputation
- Keywords
- prosthesis, osseointegration, neural transmission, magnetic beads
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 7 participants (estimated)
- Lead sponsor
- Brigham and Women's HospitalUniversity, hospital or other
- Collaborators
- Massachusetts Institute of Technology, Integrum
- Study start
- 1 May 2024 (actual)
- Primary completion
- 2 Sep 2026 (estimated)
- Study completion
- 2 May 2027 (estimated)
- First posted
- 30 Apr 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The e-OPRA Implant System, is a further development of the OPRA (Osseointegrated Prostheses for the Rehabilitation of Amputees) Implant System. The e-OPRA Implant system is an implant system for direct skeletal anchorage of amputation prostheses. The added feature in the e-OPRA Implant system, is a bidirectional interface into the human body that allows permanent and reliable communication using implanted electrodes. These electrodes will provide long-term stable bioelectric signals for an improved control of the prosthetic limb. The Magnetic Bead Tracking System, which will be implanted and used in combination with the e-OPRA Implant system, is an investigational device that consists of pairs of magnetic beads, and a set of magnetic field sensors that measure and track the length of muscles and the speed at which they move in real-time. When the beads are implanted in muscle in the residual limb of an amputee, the muscle length signal is communicated to an investigational, robotic ankle-foot prosthesis. The purpose of the study is to evaluate the feasibility of a transtibial amputee with the e-OPRA Implant System and Magnetic Bead Tracking System exhibiting full neural control over a neuro-mechanical prosthetic system.
A maximum of seven subjects will be enrolled. Each subject will undergo one or more surgeries where the e-OPRA Implant System and Magnetic Bead Tracking System will be implanted. The subjects will participate in follow-up sessions the last of which occurs approximately 24 months after the surgery. This is a prospective, non-randomized, uncontrolled study.
Detailed description
Normalization of function for individuals with limb amputation is within reach, and will be achieved by smart implants capable of bi-directional communication between brain and machine via bone-anchored, interactive, powered prosthetic components. Rehabilitation of patients with expected high physical activity level, such as after amputation due to trauma or cancer, is currently limited by dependence on an external socket for the mechanical attachment of the prosthesis to the residuum. Despite the use of advanced materials and fabrication methods, socket interfaces routinely cause sores, chafing, pain, increased energy expenditure, and a decreased quality of life. Novel surgical techniques using osseointegrated transdermal titanium implants, now validated in Europe for over 25 years, obviate the need for painful sockets by establishing a direct, load-bearing link between skeleton and prosthesis. This system also promises a transformative breakthrough in neuroprosthetics, because it allows for fully internal, high bandwidth, stable neural connections. In a paper recently published in Science Translational Medicine, implanted muscle and nerve cuff electrodes were added to the osseointegrated device, creating a bi- directional efferent-afferent interface utilizing a safe and immune-sealed osseo-conduit. Commenting on this work, the editor stated, "Osseointegration could revolutionize the field of neuroprosthetics, giving patients more intuitive control and more freedom of movement."
Investigators have sought to advance bionic prostheses with sufficient degrees of freedom for performing natural tasks, such as manipulating objects in the case of upper-extremity prostheses, or walking and running for lower-extremity systems. Nonetheless, afferent feedback has not played a major role in any clinically-viable amputation prostheses, despite being critical for biomimetic control. This deficiency can, in large part, be attributed to a lack of clinically-available methodologies for sustained communication with the peripheral nervous system. There is no existing platform capable of invasive, robust, and permanent communication with the peripheral nervous system in a high-demand clinical set- ting. Only by bringing together critical technologies and expertise will it be possible to create a bionic limb replacement system with adequate suspension, load transmission, motor control, proprioceptive feedback, and external mechatronics that resemble the mass, volume and dynamics of the missing biological limb.
To develop the most advanced clinically- viable artificial limb and achieve the next level of prosthetic technology integration, a multi-disciplinary scientific team has been assembled with members from Massachusetts Institute of Technology (MIT: Carty, Herr, Brånemark) and Brigham and Women's Hospital (BWH: Carty, Ferrone). With proprioceptive afferent feedback, we seek to demonstrate that a person with transtibial amputation can exhibit full volitional control over a neuro-mechanical prosthetic system where key walking metrics are normalized, including preferred speed, metabolism and joint dynamics. It is the view of the proposers that the scope of this research is fundamental wherein the results will be shared broadly within the scientific community.
Study design
- Primary purpose
- Device feasibility
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| eOPRA Implant System for Transtibial Amputees and Magnetic Bead Tracking System | Experimental | Device: eOPRA Implant System for Transtibial Amputees and Magnetic Bead Tracking SystemImplantation of e-OPRA Implant System and Magnetic Bead Tracking System in lower limb. |
Who may qualify
- Ages
- 22 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- Male or Female age 22-65 at the time of surgery.
- The subject must already have been implanted with the e-OPRA Implant System at the transtibial level or must have an existing unilateral or bilateral transtibial amputation or a medical condition requiring performance of a unilateral or bilateral transtibial amputation with a minimum of 8 cm of residual tibia after amputation, such that the subject will be implanted with the e-OPRA Implant System. (OPTION 1)
- If the subject does not already have the e-OPRA Implant System, 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. (OPTION 2)
- The patient must have the ability to ambulate at variable cadence (an expected lower extremity prosthesis functional level of K3 or above, as confirmed by study investigators).
- The patient must have adequate soft tissue bulk and muscle mass present in the operative limb to support appropriate wound healing.
Key exclusion criteria (12 listed)
- Subjects with any active skin disease in the tested limb.
- Subjects with 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.).
- For subjects who have not yet been implanted with the e-OPRA Implant System, subjects who would have less than 2 mm of remaining cortex bone available around the implant, if implanted.
- Subjects with advanced atrophic muscle and/or compromised soft tissue coverage in the operative limb.
- Subjects 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 subject to be a good study candidate.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| eOPRA Implant System for Transtibial Amputees and Magnetic Bead Tracking SystemAlso: eOPRA, e-Osseointegrated Prosthesis for the Rehabilitation of AmputeesThe Magnetic Bead Tracking System is an investigational device that consists of pairs of magnetic beads, and a set of magnetic field sensors that measure and track the length of muscles and the speed at which they move in real-time. When the beads are implanted in muscle in the residual limb of an amputee, the muscle length signal is communicated to an investigational, robotic ankle-foot prosthesis. The e-OPRA is an investigational implant system that lets a lower leg prosthesis attach securely to the remaining tibia bone. The e-OPRA device has been designed so that it can be implanted with an electrode set that consists of an electrical connector and electrodes to allow it to be used with both a neuro-mechanical (powered) prosthesis system, in addition to the standard prosthesis. The operation to implant these devices will represent a modification of the surgical technique currently employed for standard below knee amputation. | Device | eOPRA Implant System for Transtibial Amputees and Magnetic Bead Tracking System |
Primary outcome
number of participants out of total who undergo device implantation (aim: 7 participants) who can complete robotics testing activities
Time frame: 3 - 24 months postop for all study participants
testing activities include subject stability assessments, free space control activities using EMG, bead migration assessments, walking gait assessments and single-leg balance assessments
number of participants out of total who undergo device implantation (aim: 7 participants) who still have device successfully implanted at 24 months postop
Time frame: 24 months postop for all study participants
successful implantation at 24 months is defined as having both eOPRA Implant System and Magnetic Beads Tracking System intact with no plans for removal due to device-related safety concern
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Jul 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Matthew J Carty, MD principal investigator
Brigham and Women's Hospital
Hugh Herr, PhD principal investigator
Massachusetts Institute of Technology
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing eOPRA Implant System for Transtibial Amputees and Magnetic Bead Tracking System in people with Amputation, run by Brigham and Women's Hospital at 2 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 9 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
number of participants out of total who undergo device implantation (aim: 7 participants) who can complete robotics testing activities (time frame: 3 - 24 months postop for all study participants). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Jul 2026.