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Fall PreventionNCT07266454

Evaluating Stumble Recovery Functions of Prosthetic Knees

A study testing Prosthetic Knee (e.g Power Knee, Navii, Rheo Knee, ...) in people with Fall Prevention and Balance, Falls, run by Össur Iceland ehf at 2 sites in Iceland.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

The study aims to conduct a formative evaluation, along with verification, validation, and comparative analysis of the stumble recovery function in prosthetic devices by collecting relevant clinical data. The study will involve participants who are current users of lower-limb prosthetics. Read more about this study

Who is it for?
Ages 18 years and older
What is being tested?
Prosthetic Knee (e.g Power Knee, Navii, Rheo Knee, ...)
Type of treatment
Medical device
Could I receive a placebo?
No, everyone receives an active treatment
How many people
50 participants
Where
2 sitesIceland
Study dates
1 Dec 2025to 31 May 2030
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 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • 40 kg < body weight < 136kg
  • Cognitive ability to understand all instructions and questionnaires in the study
  • Willing and able to participate in the study and following the protocol
  • Age ≥ 18 years
  • Able to walk independently without the use of assistive device such as a cane or walker
  • Regular prosthesis users for at least 1 year with unilateral lower limb amputation at or below the transfemoral level (or equivalent level limb deficiency)

Who cannot join

  • Users with pain which can affect their mobility
  • Users with socket comfort score less than 7
  • Users with cognitive impairment
  • Pregnant Users
  • Musculoskeletal disorders or neurological conditions that affect motor function, gait or balance
  • Use of medications that are known to impair balance and coordination
  • Any other conditions deemed by the investigator to make participation unsafe

Trial locations and contacts

2 sites in 1 country.

Iceland2 sites
  • University of Iceland

    Reykjavik, 102

  • Össur Iceland ehf.

    Reykjavik, 110

Other trials in Iceland

About this study

The study aims to conduct a formative evaluation, along with verification, validation, and comparative analysis of the stumble recovery function in prosthetic devices by collecting relevant clinical data. The study will involve participants who are current users of lower-limb prosthetics. Utilizing a robust study design, data will be gathered in both controlled setting and real-world to thoroughly assess the performance, safety, and user satisfaction of the function. The scientific value of this research lies in its potential to enhance prosthetic technology, support evidence-based clinical practices, and ultimately improve the quality of life for users by reducing fall risks and increasing mobility confidence.

Being tested
Prosthetic Knee (e.g Power Knee, Navii, Rheo Knee, ...)
Keywords
amputation, falls, fall prevention, balance

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Prosthetic Knee (e.g Power Knee, Navii, Rheo Knee, ...)Device

    Participants will use one or more investigational prosthetic knee devices, which may include [list trade names, e.g., Navii, Rheo Knee, Power Knee], under different conditions as part of one or more study phases, including formative evaluation, verification, validation, and/or comparative crossover assessment. The study may include multiple device configurations or models within the prosthetic knee class, and comparative assessment against standard of care or alternative prosthetic knee devices as applicable.

Study groups in NCT07266454
Study groupRoleWhat they receive
Comprehensive Evaluation of Prosthetic Knee DevicesExperimentalParticipants enrolled in this protocol will take part in one or more sequential study phases, including formative evaluation, verification, validation, and/or comparative crossover assessment. Depending on study design and eligibility, participants may contribute to different phases, such as providing feedback on iterative prototypes (formative phase), verifying device functions (verification phase), validating device effectiveness and safety in simulated real-world conditions (validation phase), or participating in randomized crossover comparisons of device performance with various configurations and/or comparator devices (comparative phase). Each participant will be exposed to the relevant device configurations and study conditions for the specific phase(s) in which they are enrolled.
Receives: Device: Prosthetic Knee (e.g Power Knee, Navii, Rheo Knee, ...)

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. User-Perceived Safety During Use of Stumble Recovery Function Assessed by 3-Point Scale

    Safety perception will be assessed using a study-specific 3-point scale. Participants will rate their perception of safety when using the investigational device with the stumble recovery function enabled, compared to either a previous device version without this function or other similar devices. For each aspect of the new function, users will report a score: worse (0), neutral (1), or better (2).

    Measured: Assessed at the end of each device exposure period within formative (1 day use), verification (1 day use), validation (1 day use), and crossover phases (1-3 weeks use per exposure), at scheduled visits.

  2. Expert-Perceived Safety of Stumble Recovery Assessed by 3-Point Scale

    Safety perception will be assessed by researchers or engineers using a study-specific 3-point scale. Experts will rate the safety of the investigational device with the stumble recovery function enabled, compared to either a previous device version without this function or other similar devices. For each aspect of the new function, experts will report a score: worse (0), neutral (1), or better (2)

    Measured: Assessed at the end of each device exposure period within formative (1 day use), verification (1 day use), validation (1 day use), and crossover phases (1-3 weeks use per exposure), at scheduled visits.

  3. User-Perceived Stability and Confidence

    Stability and confidence rated by users (worse/neutral/better) via observation and feedback after using the new function.

    Measured: Assessed at the end of each device exposure period within formative (1 day use), verification (1 day use), validation (1 day use), and crossover phases (1-3 weeks use per exposure), at scheduled visits.

  4. Fall Rate Following Induced Perturbation Events Assessed by Direct Observation

    The outcome will be measured as the fall rate following induced perturbation events during use of the stumble recovery function. The fall rate is defined as the number of perturbation events resulting in falls divided by the total number of perturbation events, assessed by direct observation and/or video recording during controlled laboratory testing. The reduction in fall rate will be compared to baseline conditions, which may include use of non-microprocessor-controlled knees (NMPKs) or microprocessor-controlled knees (MPKs) without the stumble recovery function.

    Measured: Assessed at the end of each device exposure period within formative (1 day use), verification (1 day use), validation (1 day use), and crossover phases (1-3 weeks use per exposure), at scheduled visits.

  5. Stumble and Fall Detection Rate Assessed by Device Log Analysis

    The detection rate will be measured as the proportion of induced stumbles and falls (during controlled perturbation events) that are automatically identified by the knee's stumble recovery system. Detection will be confirmed via analysis of device event logs, which record when the system recognizes a stumble or fall. The successful detection rate is defined as the number of correctly detected stumbles and falls divided by the total number of perturbation events.

    Measured: Assessed at the end of each device exposure period within formative (1 day use), verification (1 day use), validation (1 day use), and crossover phases (1-3 weeks use per exposure), at scheduled visits.

  6. Stumble and Fall Response Trigger Rate Assessed by Device Log Analysis

    The response trigger rate will be measured as the proportion of detected stumbles and falls that result in the knee successfully initiating the appropriate response, as confirmed by device event logs. For each instance where a stumble or fall is detected by the knee's system, device logs will be analyzed to verify whether the corresponding response (e.g., stumble recovery activation, fall dampening) was triggered. The trigger rate is defined as the number of successful response triggers divided by the total number of detected stumbles and falls.

    Measured: Assessed at the end of each device exposure period within formative (1 day use), verification (1 day use), validation (1 day use), and crossover phases (1-3 weeks use per exposure), at scheduled visits.

  7. Stumble and Fall False Detection Rate Assessed by Device Log Analysis

    The false detection rate will be measured as the proportion of incorrectly detected stumbles or falls by the knee's system, as determined through analysis of device event logs during controlled testing sessions. A false detection is defined as a device-logged stumble or fall event that does not correspond to an actual perturbation or loss of balance observed by study personnel. The false detection rate is calculated as the number of incorrect detections divided by the total number of detections of stumbles and falls.

    Measured: Assessed at the end of each device exposure period within formative (1 day use), verification (1 day use), validation (1 day use), and crossover phases (1-3 weeks use per exposure), at scheduled visits.

  8. Stumble Recovery False Trigger Rate Assessed by Device Log Analysis Stumble Recovery False Trigger Rate Stumble Recovery False Trigger Rate

    The false trigger rate will be measured as the proportion of incorrect activations of the knee's stumble recovery function, determined by analysis of device event logs during controlled testing sessions. A false trigger is defined as activation of the stumble recovery response by the device in the absence of a true stumble or fall event, as verified by study personnel or video review. The false trigger rate is calculated as the number of incorrect triggers divided by the total number of stumble recovery activations.

    Measures how often the knee's stumble recovery is incorrectly activated during testing.

    Measured: Assessed at the end of each device exposure period within formative (1 day use), verification (1 day use), validation (1 day use), and crossover phases (1-3 weeks use per exposure), at scheduled visits.

  9. Fear of Falling Reduction Assessed by Falls Efficacy Scale-International (FES-I)

    Changes in fear of falling will be assessed using the Falls Efficacy Scale-International (FES-I) questionnaire. The FES-I provides a total score representing the participant's concern about falling during social and physical activities. Scores range from 16 (no concern about falling) to 64 (severe concern about falling); higher scores indicate a greater fear of falling. The outcome will be measured as the change in FES-I score from baseline (prior to use of the stumble recovery function) to after using the device with the stumble recovery function enabled.

    Measured: Assessed at the end of each device exposure period within formative (1 day use), verification (1 day use), validation (1 day use), and crossover phases (1-3 weeks use per exposure), at scheduled visits.

  10. Perceived Safety and Balance Assessed by Activities-specific Balance Confidence (ABC) Scale

    Perceived safety and balance will be assessed using the Activities-specific Balance Confidence (ABC) Scale questionnaire. The ABC Scale measures an individual's confidence in maintaining balance during various daily activities. Scores range from 0% (no confidence) to 100% (complete confidence); higher scores indicate better perceived safety and balance. The outcome will be measured as the change in ABC Scale score from baseline (using the prescribed or previous knee) to after using the device with the stumble recovery function enabled. Non-inferiority will be established if the change in score is within the minimal detectable change (MDC), set at 11.56 percentage points.

    Measured: Assessed at the end of each device exposure period within formative (1 day use), verification (1 day use), validation (1 day use), and crossover phases (1-3 weeks use per exposure), at scheduled visits.

  11. Stumble Recovery Ability Assessed by Motion Capture or Wearable Sensor Analysis

    Improvement in stumble recovery ability will be assessed by measuring recovery time, defined as the duration from stumble onset to regaining stable posture. Recovery time will be recorded during controlled perturbation events using motion capture technology or wearable sensors. Shorter recovery times indicate enhanced ability to recover from stumbles with the stumble recovery function enabled, compared to baseline device conditions.

    Measured: Assessed at the end of each device exposure period within formative (1 day use), verification (1 day use), validation (1 day use), and crossover phases (1-3 weeks use per exposure), at scheduled visits.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted5 Dec 2025
  2. Study start1 Dec 2025
  3. Primary completion31 May 2030 (estimated)
  4. Study completion31 May 2030 (estimated)

Resources

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
Not applicable
Intervention model
Sequential
Masking
None (open label)
Enrolment
50 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07266454
Sponsor's protocol ID
CIP2025012117
Status last verified
Jan 2026
First submitted
2 Sep 2025
Last updated
16 Jan 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A study testing Prosthetic Knee (e.g Power Knee, Navii, Rheo Knee, ...) in people with Fall Prevention and Balance, Falls, run by Össur Iceland ehf at 2 sites in Iceland.

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 6 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: under way, not looking for participants, as of the sponsor's last update on 16 Jan 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 Iceland. 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?

User-Perceived Safety During Use of Stumble Recovery Function Assessed by 3-Point Scale (time frame: Assessed at the end of each device exposure period within formative (1 day use), verification (1 day use), validation (1 day use), and crossover phases (1-3 weeks use per exposure), at scheduled visits.). The study lists 11 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 16 Jan 2026.

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