Intuitive Control of a Hybrid Prosthetic Leg During Ambulation

The objective of this research is to determine the clinical benefits of an innovative and lightweight powered leg controlled using our intent recognition framework in laboratory and community environments.

Study Overview

• Status: Recruiting
• Conditions: Amputation
• Intervention / Treatment: Device: Hybrid Leg; Device: Prescribed Passive Prosthesis

Detailed Description

The hypothesis of this study is that using the Hybrid Leg with seamless, automatic transitions will result in participants choosing to become more active and improve their community participation compared to when using their own passive prosthetic leg.

The Hybrid Leg is an an innovative and lightweight powered leg that has 2 operating modes: active and passive. When in active mode, the Hybrid Leg is capable of supplying 120 NM of knee torque and actively repositioning the ankle during non-weight bearing phases of gait. When in passive mode, the motor and transmission are decoupled from the knee, which then behaves like an Ottobock 3R95 passive prosthetic knee, and the non-backdriveable mechanism of the ankle allows it to behave as an energy return foot. Allowing the device to behave passively if the battery becomes depleted or the actuators become damaged is an important enabling safety factor that will allow us to complete our study.

Phase 1: We will enroll 20 subjects a clinical trial of the leg and control system who will be fit with the Hybrid Leg and receive in-lab therapy to learn how to ambulate with the device.

Phase 2: Subjects will be randomized into a clinical trial of the leg and control system with an AB-BA design; condition A - subjects own device; condition B - Hybrid Leg. Subjects will complete an extensive ambulation and community mobility training to learn optimal use of their own passive device or the Hybrid Leg. After training the subjects will complete a full biomechanical analysis for each device as they complete ambulation circuits that include standing, level-ground walking, walking on slopes and on stairs, sit-stand transitions and transitions between these activities.

Phase 3: After completing phase 2 subjects will complete 4-week trials using their assigned prosthesis (Condition A or B) at home and within their community. During the trials subjects will be monitored using mobile phone based sensors and socket mounted activity monitor to determine how often the user performs the ambulation activities.

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Suzanne Finucane; Phone Number: 312-238-0937; Email: sfinucane@sralab.org

Study Locations

• United States
  • Illinois
    • Chicago, Illinois, United States, 60611
      • Recruiting
      • Shirley Ryan AbilityLab
      • Contact: Suzanne Finucane; Phone Number: 312-238-0937; Email: sfinucane@sralab.org
      • Principal Investigator: Levi Hargrove, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 95 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• A unilateral or bilateral lower limb amputation
• K2/K3/K4 ambulator with a prosthesis
• English speaking

Exclusion Criteria:

• Significant new injury that would prevent use of a prosthesis: The ability to consistently wear a prosthesis and perform activities of daily living and specific performance tasks is necessary to evaluate the relative benefits of the interventions.

• Cognitive impairment sufficient to adversely affect understanding of or compliance with study requirements, ability to communicate experiences, or ability to give informed consent: The ability to understand and comply with requirements of the study is essential in order for the study to generate useable, reliable data. The ability to obtain relevant user feedback through questionnaires and informal discussion adds significant value to this study.

  • Significant other comorbidity: Any other medical issues or injuries that would preclude completion of the study, use of the prostheses, or that would otherwise prevent acquisition of useable data by researchers.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Condition A: Hybrid Leg; Subject will be trained on use of the experimental device, the Hybrid Leg.	Device: Hybrid Leg; The Hybrid Knee uses an actively variable transmission in combination of a passive spring/damper system. This allows the motor torque output to be adapted to the requirements of active dynamic tasks - changing the effective transmission ration from zero (fully passive) for level ground walking to a maximum value (fully active) for sit-to-stand transfers. This provides physiological knee torque and speed with a small motor and primary transmission system while also maximizing electrical efficiency, which minimized battery weight. The knee prototype weights 1.7kg. The Semi-active ankle can actively reposition during non-weight bearing phases of gait and uses a non back driveable transmission to maintain its set point during weight bearing activities.
Other: Condition B: Passive Leg; Subject will use their currently prescribed home passive prosthesis	Device: Prescribed Passive Prosthesis; Participants will participate in training sessions of community skills and advanced ambulation training for their home, prescribed passive prosthesis.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Average daily number of steps	This outcome will be assessed using an accelerometery data measured using a mobile phone during the entire 4-week home trial of each device (Hybrid Leg and prescribed home device), resulting in a pair of outcomes for each subject. Statistical analysis will be done , first using a paired t-test (which assumes no carry-over and no device sequence effects), followed by the analysis using a linear mixed model with device and sequence group as fixed effects, and subject as the random effect. We expect that sequence will not be a statistically significant predictor, but that average daily steps will be significantly different between devices, with subjects taking significantly more steps when using the Hybrid Leg.	4 weeks - data collected during 4 week home trial of each device, analyzed upon completion of 4 week home trial
Average daily number of times subject switches between activities	This outcome will be assessed using an accelerometery data measured using a mobile phone during the entire 4-week home trial of each device (Hybrid Leg and prescribed home device), resulting in a pair of outcomes for each subject. Statistical analysis will be done , first using a paired t-test (which assumes no carry-over and no device sequence effects), followed by the analysis using a linear mixed model with device and sequence group as fixed effects, and subject as the random effect. We expect that sequence will not be a statistically significant predictor, but that average transitions will be significantly different between devices, with subjects taking significantly more transitioning between activities more when using the Hybrid Leg.	4 weeks - data collected during 4 week home trial of each device, analyzed upon completion of 4 week home trial

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
10 Meter Walk Test	The 10mWT is used to assess walking speed in meters/second (m/s) over a short distance.	Lab visit prior to start of home trial and lab visit upon completion of 4 week trial with each device
GPS tracking analysis	Subject-specific map of movement within the community will be generated and investigated for individual changes in community mobility and cross-referenced with their survey results. These data could provide insight into how well patient-reported measures reflect actual community participation, although this possibility is acknowledged to be exploratory	End of each 4 week home trial
Six-Minute Walk Test	The 6MWT is a sub-maximal exercise test used to assess walking endurance and aerobic capacity. Participants will walk around the perimeter of a set circuit for a total of six minutes.	Lab visit prior to start of home trial and lab visit upon completion of 4 week trial with each device
Hill Assessment Index	The Hill Assessment Index (HAI) is a 12 level ordinal scale developed to address different characteristics of hill ascent and descent in preparation comparing different prosthetic knee units. The HAI assesses gait patterns on hills combined with assistive device usage reflecting the quality of independence.	Lab visit prior to start of home trial and lab visit upon completion of 4 week trial with each device
Stair Assessment Index	The Stair Assessment Index is a 14 level ordinal scale that assesses the functional ability of transfemoral amputees for stair ascent and descent. It is being used as a physical measurement tool to document different gait styles on the stairs.	Lab visit prior to start of home trial and lab visit upon completion of 4 week trial with each device
Berg Balance Scale	The Berg Balance Scale is a 14 item objective measure that assesses static balance and fall risk in adults.	Lab visit prior to start of home trial and lab visit upon completion of 4 week trial with each device
Functional Gait Assessment	The FGA is used to assess postural stability during walking and assesses an individual's ability to perform multiple motor tasks while walking. The tool is a modification of the 8-item Dynamic Gait Index, developed to improve reliability and reduce ceiling effect.	Lab visit prior to start of home trial and lab visit upon completion of 4 week trial with each device
5 Times Sit to Stand	The Five Times Sit to Stand Test measures one aspect of transfer skill. The test provides a method of quantify functional lower extremity strength and /or identify movement strategies a patient used to complete transitional movements.	Lab visit prior to start of home trial and lab visit upon completion of 4 week trial with each device
4 -Square Step Test	Test of dynamic balance that clinically assesses the person's ability to step over objects forward, sideways, and backwards.	Lab visit prior to start of home trial and lab visit upon completion of 4 week trial with each device
Amputee Mobility Predictor	This instrument measures the ambulatory potential of lower limb amputees with and without the use of a prosthesis. It assesses the mobility of people with lower limb amputation prior to prosthetic fitting and predicts function following prosthetic prescription.	Lab visit prior to start of home trial and lab visit upon completion of 4 week trial with each device

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prosthesis Evaluation Questionnaire	The PEQ is a self-report questionnaire containing 54 questions that provide functional outcome measures in prosthetics that are more tuned to prosthesis related changes in quality of life.	Completion of each 4 week home trial
Falls-Efficacy Scale	16 item self administered questionnaire designed to assess fear of falling in mainly community dwelling older population.	Completion of each 4 week home trial
Orthotics and Prosthetics User Survey	The OPUS is a self report questionnaire consisting of five modules. It can be used for prosthetic and orthotic programs for quality assessment, to maintain awareness of improvement in activities, to evaluate changes in patients functional status and quality of lie and to assess satisfaction with devices and services.	Completion of each 4 week home trial
World Health Organization Quality of Life Bref	The WHOQOL-BREF comprises 26 items which measure the following domains: physical health, psychological health, social relationships, and environment.	Completion of each 4 week home trial

Collaborators and Investigators

• Sponsor: Shirley Ryan AbilityLab
• Collaborators: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
• Investigators: Principal Investigator: Levi Hargrove, PhD, Shirley Ryan AbilityLab

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2018
• Primary Completion (Estimated): June 30, 2024
• Study Completion (Estimated): June 30, 2025

Study Registration Dates

• First Submitted: July 19, 2019
• First Submitted That Met QC Criteria: July 26, 2019
• First Posted (Actual): July 30, 2019

Study Record Updates

• Last Update Posted (Actual): May 17, 2024
• Last Update Submitted That Met QC Criteria: May 16, 2024
• Last Verified: May 1, 2024

More Information

Terms related to this study

• Keywords: Transfemoral Amputation
• Other Study ID Numbers: STU00209522; 2R01HD079428-05 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified individual participant data will be made available
• IPD Sharing Time Frame: Data will be available within 2 years of study completion
• IPD Sharing Access Criteria: Data requests will be reviewed by the NU IRB and requester may need to sign a data access agreement.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

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