Assist-Knee: Energy-Harvesting Knee Prosthesis

Not Applicable

Completed

Conditions: Artificial Limbs
Transfemoral Amputation

Interventions: Device: Habitual Prosthesis
Device: Assist-Knee

Registration Number: NCT04023045

Lead Sponsor: Orthocare Innovations, LLC

Brief Summary: 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 .

Detailed Description: Not available

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 3

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 & Design

Study Type: INTERVENTIONAL

Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Habitual Prosthesis	Habitual Prosthesis	Participant's prescribed prosthesis
Assist-Knee	Assist-Knee	Experimental knee prosthesis

Primary Outcome Measures

Name	Time	Method
Time to Complete Sit-to-Stand	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.)	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.

Secondary Outcome Measures

Name	Time	Method
Timed Up and Go (TUG) Test	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.)	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).
Percentage of Body Weight on Contralateral Limb at 65 Degrees Knee Flexion	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.)	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.
Time to Complete Stand-to-Sit	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.)	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.