Assist-Knee: Energy-Harvesting Knee Prosthesis

Evaluation of an Energy-Harvesting Knee Prosthesis in Transfemoral Prosthesis Users

The purpose of this research is to validate the Assist-Knee design and function by collecting pilot data during the stand-to-sit-to-stand transition in transfemoral prosthesis users when using the Assist-Knee to harvest energy and return energy .

Study Overview

• Status: Completed
• Conditions: Artificial Limbs; Transfemoral Amputation
• Intervention / Treatment: Device: Habitual Prosthesis; Device: Assist-Knee

• Study Type: Interventional
• Enrollment (Actual): 3
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Washington
    • Edmonds, Washington, United States, 98020
      • Orthocare Innovations, LLC

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Unilateral transfemoral limb loss
• At least one year post-amputation and currently successfully using a prosthesis
• Uses modular endoskeletal prosthetic components
• Has bilateral normal range of motion
• Ability to perform the following activities:
• Walking ability or ability to take steps over 10 meters
• Upright standing stability
• Stand-to-sit stability (i.e. go from a standing position to a seated position independently)
• Sit-to-stand stability (i.e. rise from a seated position independently)
• Ability to communicate individual perceptions in the English language
• Ability to provide informed consent

Exclusion Criteria:

• Confounding injury or musculoskeletal problem
• Pregnancy
• Lower limb peripheral neuropathy
• Symptomatic cardiovascular disease or chronic obstructive pulmonary disease
• Not able to read and understand English
• Use of assistive devices for sit-to-stand and stand-to-sit (e.g. canes, walkers)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Device Feasibility
• Allocation: Non-Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Habitual Prosthesis; Participant's prescribed prosthesis	Device: Habitual Prosthesis; Habitual baseline prosthesis prescribed by participant's clinician.
Experimental: Assist-Knee; Experimental knee prosthesis	Device: Assist-Knee; Assist-Knee is an experimental lower limb knee prosthesis.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time to Complete Sit-to-Stand	The amount of time, measured in seconds, needed by the subject to complete the sit-to-stand transition. At least four trials of the sit-to-stand maneuver were collected for each participant using a motion analysis system. Average and standard deviation of the time to complete the sit-to-stand transition were calculated for each participant (each participant served as their own control in this pilot study). The start of the transition was determined by participant initiation; the end of the transition was determined by the participant reaching full knee extension.	Collection at baseline
Time to Complete Sit-to-Stand	The amount of time, measured in seconds, needed by the subject to complete the sit-to-stand transition. At least four trials of the sit-to-stand maneuver were collected for each participant using a motion analysis system. Average and standard deviation of the time to complete the sit-to-stand transition were calculated for each participant (each participant served as their own control in this pilot study). The start of the transition was determined by participant initiation; the end of the transition was determined by the participant reaching full knee extension.	After acclimation to Assist-Knee (Participants are given at least 10 minutes and no more than 60 minutes to acclimate to each Assist-Knee condition for safety. After acclimating, participants will complete the maneuver to measure this outcome.)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Timed Up and Go (TUG) Test	The Timed Up and Go (TUG) test is a validated timed functional test that involves standing up from a chair, walking forward for 3 meters, turning around, walking back to the chair for 3 meter, and sitting down. Each participant completed the TUG test for three trials. Time was measured using a stopwatch. Average and standard deviation of the time to complete the TUG test were calculated for each participant (each participant served as their own control in this pilot study).	Collection at baseline
Timed Up and Go (TUG) Test	The Timed Up and Go (TUG) test is a validated timed functional test that involves standing up from a chair, walking forward for 3 meters, turning around, walking back to the chair for 3 meter, and sitting down. Each participant completed the TUG test for three trials. Time was measured using a stopwatch. Average and standard deviation of the time to complete the TUG test were calculated for each participant (each participant served as their own control in this pilot study).	After acclimation to Assist-Knee (Participants are given at least 10 minutes and no more than 60 minutes to acclimate to each Assist-Knee condition for safety. After acclimating, participants will complete the maneuver to measure this outcome.)
Time to Complete Stand-to-Sit	The amount of time, measured in seconds, needed by the subject to complete the stand-to-sit transition. At least four trials of the stand-to-sit maneuver were collected for each participant using a motion analysis system. Average and standard deviation of the time to complete the stand-to-sit transition were calculated for each participant (each participant served as their own control in this pilot study). The start of the transition was determined by participant initiation; the end of the transition was determined by the participant being seated on a chair.	Collection at baseline
Time to Complete Stand-to-Sit	The amount of time, measured in seconds, needed by the subject to complete the stand-to-sit transition. At least four trials of the stand-to-sit maneuver were collected for each participant using a motion analysis system. Average and standard deviation of the time to complete the stand-to-sit transition were calculated for each participant (each participant served as their own control in this pilot study). The start of the transition was determined by participant initiation; the end of the transition was determined by the participant being seated on a chair.	After acclimation to Assist-Knee (Participants are given at least 10 minutes and no more than 60 minutes to acclimate to each Assist-Knee condition for safety. After acclimating, participants will complete the maneuver to measure this outcome.)
Percentage of Body Weight on Contralateral Limb at 65 Degrees Knee Flexion	The percentage of body weight on the contralateral limb was determined for both stand-to-sit and sit-to-stand transitions at 65 degrees knee flexion. A force plate under the contralateral limb recorded the amount of loading on the limb during the stand-to-sit and sit-to-stand transitions. The amount of contralateral limb loading at 65 degrees knee flexion was determined and divided by the participant's total loading due to overall body weight. This value was then converted to a percentage.	Collection at baseline
Percentage of Body Weight on Contralateral Limb at 65 Degrees Knee Flexion	The percentage of body weight on the contralateral limb was determined for both stand-to-sit and sit-to-stand transitions at 65 degrees knee flexion. A force plate under the contralateral limb recorded the amount of loading on the limb during the stand-to-sit and sit-to-stand transitions. The amount of contralateral limb loading at 65 degrees knee flexion was determined and divided by the participant's total loading due to overall body weight. This value was then converted to a percentage.	After acclimation to Assist-Knee (Participants are given at least 10 minutes and no more than 60 minutes to acclimate to each Assist-Knee condition for safety. After acclimating, participants will complete the maneuver to measure this outcome.)

Collaborators and Investigators

• Sponsor: Orthocare Innovations, LLC
• Collaborators: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
• Investigators: Principal Investigator: Sarah Chang, PhD, Orthocare Innovations, LLC

Study record dates

Study Major Dates

• Study Start (Actual): July 15, 2019
• Primary Completion (Actual): February 26, 2020
• Study Completion (Actual): February 26, 2020

Study Registration Dates

• First Submitted: June 27, 2019
• First Submitted That Met QC Criteria: July 15, 2019
• First Posted (Actual): July 17, 2019

Study Record Updates

• Last Update Posted (Actual): October 18, 2023
• Last Update Submitted That Met QC Criteria: October 16, 2023
• Last Verified: October 1, 2023

More Information

Terms related to this study

• Other Study ID Numbers: 7826-01; 1R43HD097826 (U.S. NIH Grant/Contract)

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