AmputationNCT05955378
Assessing the DSR Ankle
A study testing DSR Ankle and Predicate Ankle in people with Amputation and Limb Deficiencies, run by Synchro Motion LLC at 1 site in United States.
Trial summary
This research is being done to conduct a preliminary investigation into a new prosthetic microprocessor controlled (MPC) ankle, called the Damping, Stiffness, and Repositioning (DSR) ankle. Read more about this study
- Who is it for?
- Ages 18 to 89 years
- Conditions the study is for
- Amputation, Limb Deficiencies
- What is being tested?
- DSR Ankle and Predicate Ankle
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 5 participants
- Where
- 1 siteUnited States
- Study dates
- 22 Aug 2023to 19 Dec 2024
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 18 to 89 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adults aged 18-89 years
- Patients who have a unilateral transtibial amputation who are able to use a prosthesis and who currently use a passive, non-MPC prosthesis
- K2 level ambulators
Who cannot join
- Pregnant women
- Children (<18 years old)
- Prisoners or institutionalized individuals
- Individuals who have the inability to give informed consent
- Participants unable to walk for 2 minutes without an assistive device
- Participants with complicating health conditions that interfere with the study
- Inability to read and understand the English language. As this is a pilot study with a small sample size, it is prohibitive to translate Study documents to other languages as recruitment will be from a sample of convenience.
Trial locations and contacts
1 site in 1 country.
United States1 site
Shirley Ryan AbilityLab
Chicago, Illinois, 60611-4805
About this study
Official title: Assessment of a Microprocessor Ankle for Low Mobility Individuals
This research is being done to conduct a preliminary investigation into a new prosthetic microprocessor controlled (MPC) ankle, called the Damping, Stiffness, and Repositioning (DSR) ankle. The DSR ankle is a new design to support a person while they walk on both even and uneven ground, as well as with bending the ankle for safe foot clearance while a person takes a step. In particular, in this study we are interested in seeing how this type of new device may benefit people who are rated as a K2-level ambulator.
Read the detailed description
Synchro Motion, LLC developed a novel MPC ankle. Because of its unique actuation scheme, the prosthesis can behave as: (1) a lockable conformal damper, (2) a variable set-point spring, and (3) an actively repositionable joint.
The investigators therefore refer to the device as the damping, stiffness, and repositioning (DSR) ankle. The DSR ankle is small, lightweight, quiet, and runs for multiple days on a single charge. No other commercially available prosthesis combines this set of features. It will be shown in preliminary work that the features of the DSR ankle can increase toe clearance in swing, reduce the time-to-foot-flat after heel strike, and improve weight bearing symmetry when standing on slopes for K3 Individuals with Lower Limb Amputation (ILLAs). These biomechanical functions have all been linked to improved safety and stability, which leads the investigators to hypothesize that the DSR ankle may provide benefits to K2 ILLAs as well.
The main purpose of this research is to determine the ways in which the DSR ankle may be adapted to provide benefits specifically to ILLAs who use their prosthesis at the K2 level. For purposes of the Phase I work, the development and assessment will be performed exclusively with K2 ILLAs in order to provide an opportunity to implement any necessary refinements to the DSR ankle to ensure optimal K2 performance. The remainder of the research is to quantify the effectiveness of the DSR ankle as compared to a predicate non-MPC ankle in improving performance for K2 ILLAs.
- Conditions
- Amputation, Limb Deficiencies
- Being tested
- DSR Ankle, Predicate Ankle
- Keywords
- Amputation, Transtibial, K2, Limited Community Ambulator
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
DSR AnkleDevice
Also called The Damping, Stiffness and Repositioning Ankle
This is the experimental ankle component used in the overall prosthetic intervention.
Predicate AnkleDevice
Also called Daily Use Ankle
This is the participant's prescribed ankle/foot complex used in the overall prosthetic intervention.
| Study group | Role | What they receive |
|---|---|---|
| DSR Ankle | Experimental | The DSR Ankle is a novel microprocessor-controlled ankle prosthesis that is able to provide enhanced mobility and stability to individuals with lower limb amputation. It interfaces to the user by attaching to their socket via an industry-standard pyramid connector. Receives: Device: DSR Ankle |
| Predicate Ankle | Active comparator | The predicate ankle is the user's prescribed prosthesis worn for the activities of daily living. Receives: Device: Predicate Ankle |
What is being measured
The primary outcome is the main question the study is designed to answer.
Minimum Foot Clearance
Minimum foot clearance is the shortest distance between the foot and the ground during swing, and it occurs approximately halfway through the swing phase of gait.
Measured: after up to 3 weeks of training
Time to Foot Flat
Time to foot flat is the duration of time between initial contact at heel strike and the full contact of the sole of the foot on the ground in stance.
Measured: after up to 3 weeks of training
Secondary outcomes (4)
Orthotics Prosthetics User Survey (OPUS) Device Satisfaction
The OPUS is a self-report questionnaire consisting of 5 modules. It can be used for prosthetic and orthotic programs for quality assessment, to maintain awareness of improvement in activities, to evaluate changes in patient's functional status and quality of life, and to assess satisfaction with devices and services. The Device Satisfaction module uses a 5-point Likert scale (1 to 5), with a total score range of 11 to 55. Higher values indicate higher levels of satisfaction.
Measured: after up to 3 weeks of training
10 Meter Walk Test (10 MWT)
The 10 MWT assesses walking speed in meters per second over a distance of 10 meters.
Measured: after up to 3 weeks of training
Six Minute Walk Test (6 MWT)
The 6 MWT assesses walking distance in meters over a period of 6 minutes.
Measured: after up to 3 weeks of training
Timed Up and Go (TUG)
The TUG assesses mobility, balance, walking ability, and fall risk in older adults.
Measured: after up to 3 weeks of training
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Jul 2023
- Study start22 Aug 2023
- Primary completion19 Nov 2024
- Study completion19 Dec 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for AmputationStudies of the same condition, open and under way.
- 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- AB/BA
- Masking
- None (open label)
- Enrolment
- 5 participants (actual)
Sponsor and investigators
- Lead sponsor
- Synchro Motion LLC
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Shirley Ryan AbilityLab
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05955378
- Sponsor's protocol ID
- STU00217993
- Status last verified
- Jun 2025
- First submitted
- 3 Jul 2023
- Last updated
- 1 Jul 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 1 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Assessment of a Microprocessor Ankle for Low Mobility Individuals
- ClinicalTrials.gov ID
- NCT05955378
- Acronym / sponsor ID
- STU00217993
- Conditions
- Amputation, Limb Deficiencies
- Keywords
- Amputation, Transtibial, K2, Limited Community Ambulator
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 5 participants (actual)
- Lead sponsor
- Synchro Motion LLCIndustry (pharma, biotech, devices)
- Collaborators
- Shirley Ryan AbilityLab
- Study start
- 22 Aug 2023 (actual)
- Primary completion
- 19 Nov 2024 (actual)
- Study completion
- 19 Dec 2024 (actual)
- First posted
- 21 Jul 2023 (actual)
- Results
- Posted 1 Jul 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This research is being done to conduct a preliminary investigation into a new prosthetic microprocessor controlled (MPC) ankle, called the Damping, Stiffness, and Repositioning (DSR) ankle. The DSR ankle is a new design to support a person while they walk on both even and uneven ground, as well as with bending the ankle for safe foot clearance while a person takes a step. In particular, in this study we are interested in seeing how this type of new device may benefit people who are rated as a K2-level ambulator.
Detailed description
Synchro Motion, LLC developed a novel MPC ankle. Because of its unique actuation scheme, the prosthesis can behave as: (1) a lockable conformal damper, (2) a variable set-point spring, and (3) an actively repositionable joint.
The investigators therefore refer to the device as the damping, stiffness, and repositioning (DSR) ankle. The DSR ankle is small, lightweight, quiet, and runs for multiple days on a single charge. No other commercially available prosthesis combines this set of features. It will be shown in preliminary work that the features of the DSR ankle can increase toe clearance in swing, reduce the time-to-foot-flat after heel strike, and improve weight bearing symmetry when standing on slopes for K3 Individuals with Lower Limb Amputation (ILLAs). These biomechanical functions have all been linked to improved safety and stability, which leads the investigators to hypothesize that the DSR ankle may provide benefits to K2 ILLAs as well.
The main purpose of this research is to determine the ways in which the DSR ankle may be adapted to provide benefits specifically to ILLAs who use their prosthesis at the K2 level. For purposes of the Phase I work, the development and assessment will be performed exclusively with K2 ILLAs in order to provide an opportunity to implement any necessary refinements to the DSR ankle to ensure optimal K2 performance. The remainder of the research is to quantify the effectiveness of the DSR ankle as compared to a predicate non-MPC ankle in improving performance for K2 ILLAs.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- AB/BA
| Arm | Type | Receives |
|---|---|---|
| DSR Ankle | Experimental | Device: DSR AnkleThe DSR Ankle is a novel microprocessor-controlled ankle prosthesis that is able to provide enhanced mobility and stability to individuals with lower limb amputation. It interfaces to the user by attaching to their socket via an industry-standard pyramid connector. |
| Predicate Ankle | Active comparator | Device: Predicate AnkleThe predicate ankle is the user's prescribed prosthesis worn for the activities of daily living. |
Who may qualify
- Ages
- 18 to 89 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Adults aged 18-89 years
- Patients who have a unilateral transtibial amputation who are able to use a prosthesis and who currently use a passive, non-MPC prosthesis
- K2 level ambulators
Key exclusion criteria (7 listed)
- Pregnant women
- Children (<18 years old)
- Prisoners or institutionalized individuals
- Individuals who have the inability to give informed consent
- Participants unable to walk for 2 minutes without an assistive device
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 |
|---|---|---|
| DSR AnkleAlso: The Damping, Stiffness and Repositioning AnkleThis is the experimental ankle component used in the overall prosthetic intervention. | Device | DSR Ankle |
| Predicate AnkleAlso: Daily Use AnkleThis is the participant's prescribed ankle/foot complex used in the overall prosthetic intervention. | Device | Predicate Ankle |
Primary outcome
Minimum Foot Clearance
Time frame: after up to 3 weeks of training
Minimum foot clearance is the shortest distance between the foot and the ground during swing, and it occurs approximately halfway through the swing phase of gait.
Time to Foot Flat
Time frame: after up to 3 weeks of training
Time to foot flat is the duration of time between initial contact at heel strike and the full contact of the sole of the foot on the ground in stance.
4 secondary outcomes
Orthotics Prosthetics User Survey (OPUS) Device Satisfaction
Time frame: after up to 3 weeks of training
10 Meter Walk Test (10 MWT)
Time frame: after up to 3 weeks of training
Six Minute Walk Test (6 MWT)
Time frame: after up to 3 weeks of training
Timed Up and Go (TUG)
Time frame: after up to 3 weeks of training
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 Jul 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- 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.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing DSR Ankle and Predicate Ankle in people with Amputation and Limb Deficiencies, run by Synchro Motion LLC at 1 site 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 3 inclusion and 7 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: finished, as of the sponsor's last update on 1 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site 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?
Yes. Results are posted in the registry (first posted 1 Jul 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
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?
Minimum Foot Clearance (time frame: after up to 3 weeks of training). 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 1 Jul 2025.