Clinical Investigation (Beta) of a New Developed Prosthetic Knee

Investigation on Performance of a New Developed Prosthetic Knee

The aim of this investigation is to evaluate the efficacy of the investigational device regarding performance improvements and satisfaction in descending activities for moderate to high active prosthesis users within the intended population for the investigational device. Additionally, the overall satisfaction for activities of daily living will be evaluated after a certain time of use (4 weeks home use).

Study Overview

• Status: Completed
• Conditions: Amputation
• Intervention / Treatment: Device: Navii Knee

Detailed Description

This investigation is a non-randomized single group repeated measures open label prospective design with observational and self-report measures.

Two scheduled study events are planned for amputee subjects, with 4 weeks between visits.

• Study Type: Interventional
• Enrollment (Actual): 11
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Florida
    • Orlando, Florida, United States, 32819
      • Össur Orlando

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• 45Kg< body weight < 136Kg
• Cognitive ability to understand all instructions and questionnaires in the study;
• Unilateral TF/KD amputees that are regular prosthesis users for at least 3 months
• Current MPK users (passive MPKs only) regularly performing descent activities (stairs/ramps)
• Age ≥ 18 years
• Willing and able to participate in the study and follow the protocol

Exclusion Criteria:

• Users with stump pain
• Users with socket problems
• Pregnant Users
• Users using Power Knee, Kenevo or mechanical knees as their prescribed prosthesis
• Alignment that cannot be matched with the Navii setup, as described in Instructions for use.
• Osseointegration

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• 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: Exploratory testing of a new prosthetic knee; The investigational device is provided to subjects, who then use it as their main prosthesis for a period of 4 weeks prior to returning for data collection on the device.	Device: Navii Knee; Microprocessor controlled prosthetic knee (MPK)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Satisfaction on Ramp Descent With the New Microprocessor-controlled Prosthetic Knee (MPK)	Satisfaction on ramp descent with the new MPK compared to prescribed device In-house questionnaire and Scale used: worse, same, better.	After 4 weeks of use
Satisfaction on Stair Descent With the New Microprocessor-controlled Prosthetic Knee (MPK)	Satisfaction on stair descent with the new MPK compared to prescribed device In-house questionnaire and Scale used: worse, same, better	After 4 weeks of use
Satisfaction on Level Ground Walking Activity	Satisfaction on level ground walking activity with the new MPK compared to prescribed device In-house questionnaire and Scale used: worse, same, better	After 4 weeks of use
Change in Overall Satisfaction From Baseline With Prescribed Device to After 4 Weeks of Investigational Device Use	The PEQ (Prosthesis Evaluation Questionnaire) assesses the quality of life and satisfaction for prosthetic users using a visual analog scale from 0 to 100, where higher scores indicate more positive responses. Only certain subsets were used, including the ambulation subscale, satisfaction and safety questions, and utility questions. The hypothesis tested was that the new MPK has a 95% chance of not negatively affecting overall satisfaction. If scores in Visit 2 (with the investigational device) were higher than in Visit 1 (with the prescribed device), it would support the hypothesis. The confidence interval bars represented in graph were visually compared to the margin of non-inferiority. No further statistical analysis was done.	Baseline and After 4 weeks of use
Change in Distance Walked During 2-Minute Walk Test (2MWT) From Baseline With Prescribed Device to After 4 Weeks of Investigational Device Use	Average difference in distance walked in 2MWT with the new MPK compared to comparator (prescribed device) User walk for 2 minutes in their self selected walking speed on a 30 meter track. The hypothesis being tested is that the new MPK has a 95% probability of not negatively affecting the distance walked on 2MWT. For this hypothesis, if scores in visit 2 (subjects using the investigational device) were higher than in visit 1 (subjects using their prescribed device), the difference of Visit 2 - Visit 1 would be positive and would therefore support the corresponding hypothesis. The confidence interval bars represented in graph were visually compared to the margin of non-inferiority. No further statistical analysis was done.	Baseline and After 4 weeks of use
Change in Time for the Timed Up and Go Test (TUG) From Baseline With Prescribed Device to After 4 Weeks of Investigational Device Use	The TUG test is a simple evaluative test used to measure functional mobility and assess fall risk. Reduction in time (measured in seconds) to complete indicates improvement in mobility. Average time needed to perform the TUG with the new MPK compared to comparator (prescribed device). The hypothesis being tested is that the new MPK has a 95% probability of not negatively affecting the time needed to complete the TUG. For this hypothesis, if the completion times of the TUG during the Visit 2 (subjects using the investigational device) were lower than the ones in Visit 1 (subjects using their prescribed device), the difference of Visit 2 - Visit 1 would be negative and would therefore support the corresponding hypothesis. The confidence interval bars represented in graph were visually compared to the margin of non-inferiority. No further statistical analysis was done.	Baseline and After 4 weeks of use
Change in T-score for the Prosthetic Limb Users Survey of Mobility (PLUS-M) From Baseline With Prescribed Device to After 4 Weeks of Investigational Device Use	Ability to ambulate over typical environmental obstacles is measured by the PLUS-M, using the T-score with the new MPK compared to the comparator (prescribed device). The PLUS-M is a self-report tool for assessing mobility in adults with lower limb amputation. The PLUS-M produces a T-score, which is standardized with a mean of 50 and a standard deviation of 10. Higher T-scores indicate greater mobility, with scores ranging from 17.5 to 76.6, based on responses to 44 questions. Only T-scores should be reported, as they are valid and comparable, unlike raw scores. The hypothesis being tested is that the new MPK has a 95% probability of not negatively affecting the PLUS-M score. If Visit 2 scores (using the investigational device) are higher than Visit 1 scores (using the prescribed device), the positive difference supports the hypothesis. The confidence interval bars represented in graph were visually compared to the margin of non-inferiority. No further statistical analysis was done.	Baseline and After 4 weeks of use
Change in Activities-Specific Balance Confidence Score (ABC) From Baseline With Prescribed Device to After 4 Weeks of Investigational Device Use	The ABC-scale is a 16-item questionnaire measuring confidence in performing ambulatory activities without falling, scored from 0 (no confidence) to 100 (full confidence). Cut-off scores define physical functioning: below 50% indicates low, 50-80% moderate, and above 80% high functioning. The hypothesis is that the new MPK has a 95% chance of not negatively impacting the ABC score. If Visit 2 scores (using the investigational device) exceed Visit 1 scores (using the prescribed device), it supports the hypothesis. Confidence interval bars in the graph were visually compared to the margin of non-inferiority, with no additional statistical analysis conducted.	Baseline and After 4 weeks of use

Collaborators and Investigators

• Sponsor: Össur Iceland ehf
• Investigators: Principal Investigator: Kurt N. Gruben, Ossur Americas

Study record dates

Study Major Dates

• Study Start (Actual): February 26, 2024
• Primary Completion (Actual): March 28, 2024
• Study Completion (Actual): March 28, 2024

Study Registration Dates

• First Submitted: April 17, 2024
• First Submitted That Met QC Criteria: December 23, 2024
• First Posted (Actual): December 27, 2024

Study Record Updates

• Last Update Posted (Estimated): September 4, 2025
• Last Update Submitted That Met QC Criteria: September 1, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: Amputees; Trans-femoral; Prosthetic knee
• Other Study ID Numbers: CIP2023120529

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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