AmputationNCT04212299
Transfemoral Socket Design and Muscle Function
A study testing Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS) in people with Amputation, run by University of Illinois at Chicago at 1 site in United States.
Trial summary
The objective of this pilot research project is to evaluate the effect of prosthetic socket design on amputated limb hip muscle strength and endurance in Service members, Veterans, and civilians who use above-the-knee prostheses. Read more about this study
- Who is it for?
- Ages 21 to 85 yearsHealthy volunteers can take part
- Conditions the study is for
- Amputation
- What is being tested?
- Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS)
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 5 participants
- Where
- 1 siteUnited States
- Study dates
- 24 Sep 2019to 14 Aug 2023
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 21 to 85 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Inclusion Criteria: worn an ischial containment socket for ≥ 2 years, able to walk short distances (10 meters), ability to read, write, and speak English, ≥ 2 years using a liner-based suspension, and a residual limb length ≥ 5".
Exclusion Criteria: amputation of a second leg, contralateral complications (e.g., hip replacement), or other major neuromusculoskeletal or cardiovascular conditions (e.g., heart failure).
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Illinois at Chicago
Chicago, Illinois, 60612
About this study
Official title: A Pilot Clinical Trial to Assess the Effect of Transfemoral Socket Design on Hip Muscle Function
The objective of this pilot research project is to evaluate the effect of prosthetic socket design on amputated limb hip muscle strength and endurance in Service members, Veterans, and civilians who use above-the-knee prostheses. Traditional above-the-knee socket designs provide pelvic support that interferes with hip motion. They may also reduce the effort required from amputated limb hip muscles to stabilize the hip and amputated limb, risking further loss of muscle mass and strength beyond that due to amputation. Long-standing use of above-the-knee sockets with pelvic support may therefore intensify amputated limb muscle loss and weakness, leading to challenges with walking and balance, increasing the effort required to walk, and contributing to degenerative changes in the hips and knees. Alternative socket designs that lessen the loss of muscle mass and strength are therefore required.
The investigators have developed a new socket without pelvic support for above-the-knee prosthesis users called the Northwestern University Flexible Sub-Ischial Suction (NU-FlexSIS) Socket. This new socket design increases user comfort and is often preferred by users over sockets with pelvic support. This new socket does not lessen the mechanical function of the socket, or walking and balance performance. Our recent research suggests that walking with this new socket may also increase amputated limb hip muscle size. However, more research is needed to demonstrate that this new socket design improves amputated limb hip muscle strength and endurance, leading to better function.
Read more
A socket design that increases amputated limb hip muscle strength and endurance would provide a simple way to restore amputated limb hip muscle weakness in above-the-knee prosthesis users. Despite a considerable decrease in hip muscle size and strength due to amputation surgery, amputated limb hip muscles are expected to compensate for the loss of knee and ankle function by providing stability and propulsion during walking. Walking in the new socket design without pelvic support is expected to increase amputated limb hip muscle strength and endurance, providing an appealing alternative to traditional resistance training in order to retain hip muscle strength. Unlike traditional resistance training, using this new socket design would not require additional time or equipment, and may be effective just by walking in the home, community, or workplace. Due to existing infrastructure (e.g., ongoing clinical adoption of the NU-FlexSIS Socket, existing instructional materials and courses for fabrication and fitting of the NU-FlexSIS Socket, as well as a continuing partnership with Chicago's largest provider of prosthetic clinical care), the investigators anticipate being able to translate our research results to clinical practice by the end of the project period.
The investigators expect the results of the proposed pilot research project to directly and positively benefit the health and well-being of Service members, Veterans, and civilians who are above-the-knee prosthesis users. Benefits of increasing amputated limb hip muscle strength and endurance may include: i) improved control over the prosthesis, ii) better balance, iii) reduced effort to walk, and iv) protection against joint degeneration. For Service members these benefits could improve their performance on challenging and/or uneven ground, and increase the distance and speed they can walk or run. For Veterans, these benefits could lead to greater independence during activities of daily living, and fewer falls, reducing the physical and emotional burden on family members and caregivers.
- Conditions
- Amputation
- Being tested
- Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS)
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS)Device
The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal.
Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA).
| Study group | Role | What they receive |
|---|---|---|
| Baseline ischial containment to subischial socket | Experimental | Not described Receives: Device: Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Residual Limb Hip Muscle Peak Torque at Baseline
Hip flexor, extensor, adductor and abductor muscle strength will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular strength will be assessed via average peak torque (i.e., highest torque) across the first three repetitions of 12.
Measured: Baseline
Residual Limb Hip Muscle Peak Torque at 8-weeks
Hip flexor, extensor, adductor and abductor muscle strength will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular strength will be assessed via average peak torque (i.e., highest torque) across the first three repetitions of 12. Comparison will be made to baseline measure.
Measured: 8 weeks after intervention
Residual Limb Hip Muscle Peak Torque at 42-weeks
Hip flexor, extensor, adductor and abductor muscle strength will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular strength will be assessed via average peak torque (i.e., highest torque) across the first three repetitions of 12. Comparison will be made to baseline measure.
Measured: 42 weeks after intervention
Residual Limb Hip Muscle Endurance at Baseline
Hip flexor, extensor, adductor and abductor muscle endurance will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular endurance will be assessed via a fatigue index, calculated as a percentage of the difference between total work performed during the first and last 3 repetitions divided by total work over the first 3 repetitions. A higher fatigue index will be taken as evidence of reduced muscular endurance.
Measured: Baseline
Residual Limb Hip Muscle Endurance at 8-weeks
Hip flexor, extensor, adductor and abductor muscle endurance will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular endurance will be assessed via a fatigue index, calculated as a percentage of the difference between total work performed during the first and last 3 repetitions divided by total work over the first 3 repetitions. A higher fatigue index will be taken as evidence of reduced muscular endurance. Comparison will be made to baseline measure.
Measured: 8 weeks after intervention
Residual Limb Hip Muscle Endurance at 42-weeks
Hip flexor, extensor, adductor and abductor muscle endurance will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular endurance will be assessed via a fatigue index, calculated as a percentage of the difference between total work performed during the first and last 3 repetitions divided by total work over the first 3 repetitions. A higher fatigue index will be taken as evidence of reduced muscular endurance. Comparison will be made to baseline measure.
Measured: 42 weeks after intervention
Residual Limb Hip Muscle Duration at Baseline
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The duration of time each hip muscle was active during a stride was calculated as the percentage of the gait cycle (i.e., heel-strike to heel-strike) for which that EMG signal was above a baseline value (min: 0%, max: 100%). The larger the percentage of the gait cycle that a muscle was deemed to be active, the greater its duration.
Measured: Baseline
Residual Limb Hip Muscle Duration at 8-weeks
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The duration of time each hip muscle was active during a stride was calculated as the percentage of the gait cycle (i.e., heel-strike to heel-strike) for which that EMG signal was above a baseline value (min: 0%, max: 100%). The larger the percentage of the gait cycle that a muscle was deemed to be active, the greater its duration.
Measured: 8 weeks after intervention
Residual Limb Hip Muscle Duration at at 42-weeks
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The duration of time each hip muscle was active during a stride was calculated as the percentage of the gait cycle (i.e., heel-strike to heel-strike) for which that EMG signal was above a baseline value (min: 0%, max: 100%). The larger the percentage of the gait cycle that a muscle was deemed to be active, the greater its duration.
Measured: 42 weeks
Residual Limb Hip Muscle Integrated Area at Baseline
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The total amount of hip muscle activity was calculated as the integrated area under the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles and multiple by 100. The integrated areas is therefore reported as a percentage of that maximum (min: 0%, max: 100%). The larger the integrated area the more the muscle was deemed to be active.
Measured: Baseline
Residual Limb Hip Muscle Integrated Area at 8-weeks
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The total amount of hip muscle activity was calculated as the integrated area under the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles and multiple by 100. The integrated areas is therefore reported as a percentage of that maximum (min: 0%, max: 100%). The larger the integrated area the more the muscle was deemed to be active.
Measured: 8 weeks after intervention
Residual Limb Hip Muscle Integrated Area at 42-weeks
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The total amount of hip muscle activity was calculated as the integrated area under the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles and multiple by 100. The integrated areas is therefore reported as a percentage of that maximum (min: 0%, max: 100%). The larger the integrated area the more the muscle was deemed to be active.
Measured: 42 weeks after intervention
Peak Residual Limb Hip Muscle Activity at Baseline
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The highest level of hip muscle activity was calculated as the peak of the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles recorded during baseline). The peak EMG is therefore typically reported as a value between 0 and 1. However, if the peak value during assessments increases relative to baseline, the value of the peak activity will exceed 1. The larger the peak value the greater the activation of that muscle.
Measured: Baseline
Peak Residual Limb Hip Muscle Activity at 8 Weeks
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The highest level of hip muscle activity was calculated as the peak of the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles recorded during baseline). The peak EMG is therefore typically reported as a value between 0 and 1. However, if the peak value during assessments increases relative to baseline, the value of the peak activity will exceed 1. The larger the peak value the greater the activation of that muscle.
Measured: 8 weeks after intervention
Peak Residual Limb Hip Muscle Activity at 42 Weeks
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The highest level of hip muscle activity was calculated as the peak of the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles recorded during baseline). The peak EMG is therefore typically reported as a value between 0 and 1. However, if the peak value during assessments increases relative to baseline, the value of the peak activity will exceed 1. The larger the peak value the greater the activation of that muscle.
Measured: 42 weeks after intervention
Secondary outcomes (21)
Four Square Step Test at Baseline
A test of dynamic balance and coordination that assesses the participant's ability to step over objects forward, sideways, and backwards. Test was administered and scored as the best time (i.e., fastest) of two trials.
Measured: Baseline
Four Square Step Test at 8 Weeks
A test of dynamic balance and coordination that assesses the participant's ability to step over objects forward, sideways, and backwards. Test was administered and scored as the best time (i.e., fastest) of two trials.
Measured: 8-weeks after intervention
Four Square Step Test at 42 Weeks
A test of dynamic balance and coordination that assesses the participant's ability to step over objects forward, sideways, and backwards. Test was administered and scored as the best time (i.e., fastest) of two trials.
Measured: 42-weeks after intervention
One Leg Stance Test at Baseline
A test of static balance that assesses the participant's ability to remain upright on one leg. Test was administered and scored as the best time (i.e., longest) of two trials. Longer times imply better static balance.
Measured: Baseline
One Leg Stance Test at 8 Weeks
A test of static balance that assesses the participant's ability to remain upright on one leg. Test was administered and scored as the best time (i.e., longest) of two trials. Longer times imply better static balance.
Measured: 8 weeks after intervention
One Leg Stance Test at 42 Weeks
A test of static balance that assesses the participant's ability to remain upright on one leg. Test was administered and scored as the best time (i.e., longest) of two trials. Longer times imply better static balance.
Measured: 42 weeks after intervention
10-Meter Walk Test at Baseline
The 10MWT assesses walking speed in meters per second over a short duration. A faster speed is consider better walking performance. The fastest of 2 trials was used.
Measured: Baseline
10-Meter Walk Test at 8 Weeks
The 10MWT assesses walking speed in meters per second over a short duration. A faster speed is consider better walking performance. The fastest of 2 trials was used.
Measured: 8 weeks after intervention
10-Meter Walk Test at 42 Weeks
The 10MWT assesses walking speed in meters per second over a short duration. A faster speed is consider better walking performance. The fastest of 2 trials was used.
Measured: 42 weeks after intervention
2-Minute Walk Test at Baseline
The 2-Minute Walk Test is a measurement of waking endurance that assesses walking distance over two minutes. A longer distance walked indicates greater walking endurance.
Measured: Baseline
2-Minute Walk Test at 8 Weeks
The 2-Minute Walk Test is a measurement of waking endurance that assesses walking distance over two minutes. A longer distance walked indicates greater walking endurance.
Measured: 8-weeks after intervention.
2-Minute Walk Test at 42 Weeks
The 2-Minute Walk Test is a measurement of waking endurance that assesses walking distance over two minutes. A longer distance walked indicates greater walking endurance.
Measured: 42-weeks after intervention.
Volume of Physical Activity at Baseline
To assess the volume of physical activity, transfemoral prosthesis users wore a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from the step count data. The volume of physical activity will be quantified by the mean number of steps per activity bout. Higher values will be taken as evidence of greater physical activity.
Measured: 2 weeks prior to intervention (baseline)
Volume of Physical Activity at 8 Weeks
To assess the volume of physical activity, transfemoral prosthesis users wore a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from the step count data. The volume of physical activity will be quantified by the mean number of steps per activity bout. Higher values will be taken as evidence of greater physical activity.
Measured: 8-weeks after intervention
Volume of Physical Activity at 42 Weeks
To assess the volume of physical activity, transfemoral prosthesis users wore a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from the step count data. The volume of physical activity will be quantified by the mean number of steps per activity bout. Higher values will be taken as evidence of greater physical activity.
Measured: 42-weeks after intervention
Frequency of Physical Activity at Baseline
To assess the frequency of physical activity, transfemoral prosthesis users will wear a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from step count data. The frequency of physical activity will be quantified by the mean number of activity bouts per day. Higher values will be taken as evidence of greater physical activity.
Measured: 2 weeks prior to intervention (baseline)
Frequency of Physical Activity at 8 Weeks
To assess the frequency of physical activity, transfemoral prosthesis users will wear a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from step count data. The frequency of physical activity will be quantified by the mean number of activity bouts per day. Higher values will be taken as evidence of greater physical activity.
Measured: 8 weeks after intervention
Frequency of Physical Activity at 42 Weeks
To assess the frequency of physical activity, transfemoral prosthesis users will wear a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from step count data. The frequency of physical activity will be quantified by the mean number of activity bouts per day. Higher values will be taken as evidence of greater physical activity.
Measured: 42 weeks after intervention
Duration of Physical Activity at Baseline
To assess the duration of physical activity, transfemoral prosthesis users will wear a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from step count data. The duration of physical activity will be quantified by the mean time (in minutes) of activity bouts per day. Higher values will be taken as evidence of greater physical activity.
Measured: 2 weeks prior to intervention (baseline)
Duration of Physical Activity at 8 Weeks
To assess the duration of physical activity, transfemoral prosthesis users will wear a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from step count data. The duration of physical activity will be quantified by the mean time (in minutes) of activity bouts per day. Higher values will be taken as evidence of greater physical activity.
Measured: 8 weeks after intervention
Duration of Physical Activity at 42 Weeks
To assess the duration of physical activity, transfemoral prosthesis users will wear a StepWatch4 activity monitor (Modus Health, Edmonds, WA) for a 2-week period. Activity bouts, or periods of time in which steps occur in successive 10-second intervals, will be derived from step count data. The duration of physical activity will be quantified by the mean time (in minutes) of activity bouts per day. Higher values will be taken as evidence of greater physical activity.
Measured: 42 weeks after intervention
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Dec 2019
- Study start24 Sep 2019
- Primary completion23 Sep 2022
- Study completion14 Aug 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for AmputationStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- Transfemoral amputees who historically have worn an ischial containment prosthetic socket will be assessed at baseline, fit with the intervention (a sub-ischial socket), and then tested at 8 and 42 weeks after intervention. All comparisons will be made back to baseline.
- Masking
- None (open label)
- Enrolment
- 5 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Illinois at Chicago
- Sponsor type
- University, hospital or other
- Collaborators
- Northwestern University
- Responsible party
- Principal investigator, Andrew Sawers, University of Illinois at Chicago
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04212299
- Sponsor's protocol ID
- 2019-0725
- Other IDs
- W81XWH1910507
- Status last verified
- Sep 2024
- First submitted
- 20 Dec 2019
- Last updated
- 10 Oct 2024
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 10 Oct 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Pilot Clinical Trial to Assess the Effect of Transfemoral Socket Design on Hip Muscle Function
- ClinicalTrials.gov ID
- NCT04212299
- Acronym / sponsor ID
- 2019-0725
- Conditions
- Amputation
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 5 participants (actual)
- Lead sponsor
- University of Illinois at ChicagoUniversity, hospital or other
- Collaborators
- Northwestern University
- Study start
- 24 Sep 2019 (actual)
- Primary completion
- 23 Sep 2022 (actual)
- Study completion
- 14 Aug 2023 (actual)
- First posted
- 26 Dec 2019 (actual)
- Results
- Posted 10 Oct 2024
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The objective of this pilot research project is to evaluate the effect of prosthetic socket design on amputated limb hip muscle strength and endurance in Service members, Veterans, and civilians who use above-the-knee prostheses. Traditional above-the-knee socket designs provide pelvic support that interferes with hip motion. They may also reduce the effort required from amputated limb hip muscles to stabilize the hip and amputated limb, risking further loss of muscle mass and strength beyond that due to amputation. Long-standing use of above-the-knee sockets with pelvic support may therefore intensify amputated limb muscle loss and weakness, leading to challenges with walking and balance, increasing the effort required to walk, and contributing to degenerative changes in the hips and knees. Alternative socket designs that lessen the loss of muscle mass and strength are therefore required.
The investigators have developed a new socket without pelvic support for above-the-knee prosthesis users called the Northwestern University Flexible Sub-Ischial Suction (NU-FlexSIS) Socket. This new socket design increases user comfort and is often preferred by users over sockets with pelvic support. This new socket does not lessen the mechanical function of the socket, or walking and balance performance. Our recent research suggests that walking with this new socket may also increase amputated limb hip muscle size. However, more research is needed to demonstrate that this new socket design improves amputated limb hip muscle strength and endurance, leading to better function.
A socket design that increases amputated limb hip muscle strength and endurance would provide a simple way to restore amputated limb hip muscle weakness in above-the-knee prosthesis users. Despite a considerable decrease in hip muscle size and strength due to amputation surgery, amputated limb hip muscles are expected to compensate for the loss of knee and ankle function by providing stability and propulsion during walking. Walking in the new socket design without pelvic support is expected to increase amputated limb hip muscle strength and endurance, providing an appealing alternative to traditional resistance training in order to retain hip muscle strength. Unlike traditional resistance training, using this new socket design would not require additional time or equipment, and may be effective just by walking in the home, community, or workplace. Due to existing infrastructure (e.g., ongoing clinical adoption of the NU-FlexSIS Socket, existing instructional materials and courses for fabrication and fitting of the NU-FlexSIS Socket, as well as a continuing partnership with Chicago's largest provider of prosthetic clinical care), the investigators anticipate being able to translate our research results to clinical practice by the end of the project period.
The investigators expect the results of the proposed pilot research project to directly and positively benefit the health and well-being of Service members, Veterans, and civilians who are above-the-knee prosthesis users. Benefits of increasing amputated limb hip muscle strength and endurance may include: i) improved control over the prosthesis, ii) better balance, iii) reduced effort to walk, and iv) protection against joint degeneration. For Service members these benefits could improve their performance on challenging and/or uneven ground, and increase the distance and speed they can walk or run. For Veterans, these benefits could lead to greater independence during activities of daily living, and fewer falls, reducing the physical and emotional burden on family members and caregivers.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- Transfemoral amputees who historically have worn an ischial containment prosthetic socket will be assessed at baseline, fit with the intervention (a sub-ischial socket), and then tested at 8 and 42 weeks after intervention. All comparisons will be made back to baseline.
| Arm | Type | Receives |
|---|---|---|
| Baseline ischial containment to subischial socket | Experimental | Device: Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS) |
Who may qualify
- Ages
- 21 to 85 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS)The sub-ischial socket includes a firm, compressive, preferably cylindrical, fabric-covered silicone liner, a flexible inner socket, and a shorter rigid outer socket. The socket has proximal trim lines that do not impinge on the pelvis; they terminate distal to the ischial tuberosity and greater trochanter. For the NU-FlexSIS Socket, passive suction suspension is achieved using a one way valve and a liner with an internal seal. Since the prosthetic socket is a custom-made device, it is considered Class I exempt by the Food and Drug Administration (FDA). | Device | Baseline ischial containment to subischial socket |
Primary outcome
Residual Limb Hip Muscle Peak Torque at Baseline
Time frame: Baseline
Hip flexor, extensor, adductor and abductor muscle strength will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular strength will be assessed via average peak torque (i.e., highest torque) across the first three repetitions of 12.
Residual Limb Hip Muscle Peak Torque at 8-weeks
Time frame: 8 weeks after intervention
Hip flexor, extensor, adductor and abductor muscle strength will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular strength will be assessed via average peak torque (i.e., highest torque) across the first three repetitions of 12. Comparison will be made to baseline measure.
Residual Limb Hip Muscle Peak Torque at 42-weeks
Time frame: 42 weeks after intervention
Hip flexor, extensor, adductor and abductor muscle strength will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular strength will be assessed via average peak torque (i.e., highest torque) across the first three repetitions of 12. Comparison will be made to baseline measure.
Residual Limb Hip Muscle Endurance at Baseline
Time frame: Baseline
Hip flexor, extensor, adductor and abductor muscle endurance will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular endurance will be assessed via a fatigue index, calculated as a percentage of the difference between total work performed during the first and last 3 repetitions divided by total work over the first 3 repetitions. A higher fatigue index will be taken as evidence of reduced muscular endurance.
Residual Limb Hip Muscle Endurance at 8-weeks
Time frame: 8 weeks after intervention
Hip flexor, extensor, adductor and abductor muscle endurance will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular endurance will be assessed via a fatigue index, calculated as a percentage of the difference between total work performed during the first and last 3 repetitions divided by total work over the first 3 repetitions. A higher fatigue index will be taken as evidence of reduced muscular endurance. Comparison will be made to baseline measure.
Residual Limb Hip Muscle Endurance at 42-weeks
Time frame: 42 weeks after intervention
Hip flexor, extensor, adductor and abductor muscle endurance will be measured in transfemoral prosthesis users using a motor-driven isokinetic dynamometer. Muscular endurance will be assessed via a fatigue index, calculated as a percentage of the difference between total work performed during the first and last 3 repetitions divided by total work over the first 3 repetitions. A higher fatigue index will be taken as evidence of reduced muscular endurance. Comparison will be made to baseline measure.
Residual Limb Hip Muscle Duration at Baseline
Time frame: Baseline
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The duration of time each hip muscle was active during a stride was calculated as the percentage of the gait cycle (i.e., heel-strike to heel-strike) for which that EMG signal was above a baseline value (min: 0%, max: 100%). The larger the percentage of the gait cycle that a muscle was deemed to be active, the greater its duration.
Residual Limb Hip Muscle Duration at 8-weeks
Time frame: 8 weeks after intervention
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The duration of time each hip muscle was active during a stride was calculated as the percentage of the gait cycle (i.e., heel-strike to heel-strike) for which that EMG signal was above a baseline value (min: 0%, max: 100%). The larger the percentage of the gait cycle that a muscle was deemed to be active, the greater its duration.
Residual Limb Hip Muscle Duration at at 42-weeks
Time frame: 42 weeks
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The duration of time each hip muscle was active during a stride was calculated as the percentage of the gait cycle (i.e., heel-strike to heel-strike) for which that EMG signal was above a baseline value (min: 0%, max: 100%). The larger the percentage of the gait cycle that a muscle was deemed to be active, the greater its duration.
Residual Limb Hip Muscle Integrated Area at Baseline
Time frame: Baseline
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The total amount of hip muscle activity was calculated as the integrated area under the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles and multiple by 100. The integrated areas is therefore reported as a percentage of that maximum (min: 0%, max: 100%). The larger the integrated area the more the muscle was deemed to be active.
Residual Limb Hip Muscle Integrated Area at 8-weeks
Time frame: 8 weeks after intervention
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The total amount of hip muscle activity was calculated as the integrated area under the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles and multiple by 100. The integrated areas is therefore reported as a percentage of that maximum (min: 0%, max: 100%). The larger the integrated area the more the muscle was deemed to be active.
Residual Limb Hip Muscle Integrated Area at 42-weeks
Time frame: 42 weeks after intervention
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The total amount of hip muscle activity was calculated as the integrated area under the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles and multiple by 100. The integrated areas is therefore reported as a percentage of that maximum (min: 0%, max: 100%). The larger the integrated area the more the muscle was deemed to be active.
Peak Residual Limb Hip Muscle Activity at Baseline
Time frame: Baseline
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The highest level of hip muscle activity was calculated as the peak of the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles recorded during baseline). The peak EMG is therefore typically reported as a value between 0 and 1. However, if the peak value during assessments increases relative to baseline, the value of the peak activity will exceed 1. The larger the peak value the greater the activation of that muscle.
Peak Residual Limb Hip Muscle Activity at 8 Weeks
Time frame: 8 weeks after intervention
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The highest level of hip muscle activity was calculated as the peak of the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles recorded during baseline). The peak EMG is therefore typically reported as a value between 0 and 1. However, if the peak value during assessments increases relative to baseline, the value of the peak activity will exceed 1. The larger the peak value the greater the activation of that muscle.
Peak Residual Limb Hip Muscle Activity at 42 Weeks
Time frame: 42 weeks after intervention
Electromyographic (EMG) signals were recorded from transfemoral prosthesis users' residual limb muscles while walking. The highest level of hip muscle activity was calculated as the peak of the EMG signal during a gait cycle (i.e., heel-strike to heel-strike). Each EMG signal was normalized (i.e., divided by its maximum value across all the gait cycles recorded during baseline). The peak EMG is therefore typically reported as a value between 0 and 1. However, if the peak value during assessments increases relative to baseline, the value of the peak activity will exceed 1. The larger the peak value the greater the activation of that muscle.
21 secondary outcomes
Four Square Step Test at Baseline
Time frame: Baseline
Four Square Step Test at 8 Weeks
Time frame: 8-weeks after intervention
Four Square Step Test at 42 Weeks
Time frame: 42-weeks after intervention
One Leg Stance Test at Baseline
Time frame: Baseline
One Leg Stance Test at 8 Weeks
Time frame: 8 weeks after intervention
One Leg Stance Test at 42 Weeks
Time frame: 42 weeks after intervention
10-Meter Walk Test at Baseline
Time frame: Baseline
10-Meter Walk Test at 8 Weeks
Time frame: 8 weeks after intervention
10-Meter Walk Test at 42 Weeks
Time frame: 42 weeks after intervention
2-Minute Walk Test at Baseline
Time frame: Baseline
2-Minute Walk Test at 8 Weeks
Time frame: 8-weeks after intervention.
2-Minute Walk Test at 42 Weeks
Time frame: 42-weeks after intervention.
Volume of Physical Activity at Baseline
Time frame: 2 weeks prior to intervention (baseline)
Volume of Physical Activity at 8 Weeks
Time frame: 8-weeks after intervention
Volume of Physical Activity at 42 Weeks
Time frame: 42-weeks after intervention
Frequency of Physical Activity at Baseline
Time frame: 2 weeks prior to intervention (baseline)
Frequency of Physical Activity at 8 Weeks
Time frame: 8 weeks after intervention
Frequency of Physical Activity at 42 Weeks
Time frame: 42 weeks after intervention
Duration of Physical Activity at Baseline
Time frame: 2 weeks prior to intervention (baseline)
Duration of Physical Activity at 8 Weeks
Time frame: 8 weeks after intervention
Duration of Physical Activity at 42 Weeks
Time frame: 42 weeks after intervention
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Oct 2024.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Northwestern University Flexible Sub-Ischial Suction Socket (NU-FlexSIS) in people with Amputation, run by University of Illinois at Chicago at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
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: finished, as of the sponsor's last update on 10 Oct 2024. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. 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?
Yes. Results are posted in the registry (first posted 10 Oct 2024). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
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?
Residual Limb Hip Muscle Peak Torque at Baseline (time frame: Baseline). The study lists 15 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 10 Oct 2024.