Functional Performance Evaluation of NU-FlexSIV Socket

Functional Performance Evaluation of the Northwestern University Flexible Sub-Ischial Vacuum (NU-FlexSIV) Socket for Persons With Transfemoral Amputation

The overall objective of this study is to provide a more comfortable and functional prosthetic socket for persons with transfemoral amputation that will ultimately improve their quality of life.

Study Overview

• Status: Completed
• Conditions: Amputation; Artificial Limbs
• Intervention / Treatment: Device: Northwestern University Flexible Sub-Ischial Vacuum Socket; Device: Ischial Containment Socket

Detailed Description

The proposed clinical trial will be an assessor-blinded prospective randomized cross-over trial wherein participants with unilateral transfemoral amputation will be randomized to using one of two socket conditions (i.e., sub-ischial or ischial containment) before crossing over to the other socket condition. Random allocation (computer-generated) utilizing blocks of random size will be used to assign the initial treatment condition. The trial will be balanced such that all subjects will receive all treatments (i.e., both socket conditions) and that all subjects will participate for the same number of periods (i.e., two). While a washout period is not strictly necessary, it is effectively included as subjects will need to transition back to their usual, pre-study socket/prosthesis while the second test socket is fabricated.

Allocation of intervention will be concealed from the investigators until after a subject is enrolled. The starting socket design will be enclosed in sequentially numbered, opaque, sealed envelopes. Envelopes will be opened sequentially and only after the participant's name and other details are written on the appropriate envelope.

Blinding of prosthetic interventions is challenging given that they are devices that must be custom-fabricated and donned each day by the subject. Hence, for this study only the assessor will be blinded. The blinded assessor will be responsible for administration of the clinical performance and patient-reported measures as well as processing of motion analysis data.

• Study Type: Interventional
• Enrollment (Actual): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Illinois
    • Chicago, Illinois, United States, 60611
      • Jesse Brown VA Medical Center Motion Analysis Research Laboratory
    • Chicago, Illinois, United States, 60611
      • Northwestern University Prosthetics-Orthotics Center
    • Oakbrook Terrace, Illinois, United States, 60181
      • Scheck and Siress Prosthetics Orthotics

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• unilateral transfemoral amputation
• have used a prosthesis for two or more years
• have a residual limb that is stable in volume and free from wounds
• be physically fit enough to participate in the performance tests (Medicare Functional Classification Level K3 or K4)
• have no previous experience of the sub-ischial socket
• able to complete all visits for the duration of the protocol

Exclusion Criteria:

• have a residual limb femur of less than 5-inches
• co-morbidities that affect function, including neurologic abnormalities (e.g. neuropathic pain that would interfere with the study)
• do not speak and read English

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: NU-FlexSIV Socket; The Northwestern University Flexible Sub-Ischial Vacuum Socket is a novel socket design for transfemoral amputees.	Device: Northwestern University Flexible Sub-Ischial Vacuum Socket; NU-FlexSIV sockets have lower proximal trim lines, do not impinge on the pelvis, are highly flexible so as to allow better comfort during sitting and when muscles move within the socket during activity, and are held securely to the residual limb by suction from a vacuum pump and from compression exerted by the deliberately undersized liner and socket.; Other Names: NU-FlexSIV Socket; Device: Ischial Containment Socket; Ischial Containment (IC) sockets are more rigid and have a narrower medio-lateral dimension than anterior-posterior dimension. The socket encapsulates the ischium, ischial ramus and greater trochanter, limiting hip range of motion and comfort.; Other Names: IC Socket
Active Comparator: IC Socket; The Ischial Containment Socket is the standard of care socket design for transfemoral amputees.	Device: Northwestern University Flexible Sub-Ischial Vacuum Socket; NU-FlexSIV sockets have lower proximal trim lines, do not impinge on the pelvis, are highly flexible so as to allow better comfort during sitting and when muscles move within the socket during activity, and are held securely to the residual limb by suction from a vacuum pump and from compression exerted by the deliberately undersized liner and socket.; Other Names: NU-FlexSIV Socket; Device: Ischial Containment Socket; Ischial Containment (IC) sockets are more rigid and have a narrower medio-lateral dimension than anterior-posterior dimension. The socket encapsulates the ischium, ischial ramus and greater trochanter, limiting hip range of motion and comfort.; Other Names: IC Socket

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Socket Comfort Score (SCS) Between IC Socket and NU-FlexSIV Sockets at 7 Weeks.	Socket comfort was assessed after each socket was worn for 7 weeks. SCS is an ordinal scale where the subject responds to the question, "On a 0 to 10 scale, if 0 represents the most uncomfortable socket fit you can imagine, and 10 represents the most comfortable socket fit, how would you score the comfort of the socket of your artificial limb at the moment?"	7 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Walking Speed Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.	Walking speed was assessed after each socket was worn for 7 weeks. Participants walked along a 12 meter, level walkway at their normal self-selected speed. Marker based motion capture was used to assess walking speed (m/s).	7 weeks
Step Length Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.	Step length was assessed after each socket was worn for 7 weeks. Participants walked along a 12 meter, level walkway at their normal self-selected speed. Marker based motion capture was used to assess step length (cm).	7 weeks
Hip Extension Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.	Hip extension was assessed after each socket was worn for 7 weeks. Participants walked along a 12 meter, level walkway at their normal self-selected speed. Marker based motion capture was used to assess hip extension (degrees).	7 weeks
Hip Range of Motion Between the IC Socket and NU-FlexSIV Socket 7 Weeks.	Hip range of motion was assessed after each socket was worn for 7 weeks. Participants walked along a 12 meter, level walkway at their normal self-selected speed. Marker based motion capture was used to assess hip range of motion (degrees).	7 weeks
Trunk Motion Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.	Trunk motion was assessed after each socket was worn for 7 weeks. Participants walked along a 12 meter, level walkway at their normal self-selected speed. Marker based motion capture was used to assess trunk motion (degrees).	7 weeks
Orthotics and Prosthetics Users' Survey (OPUS) Lower-Extremity Functional Status Measure Between the IC Socket and NU-FlexSIV Socket at 7 Weeks	Lower-Extremity Functional Status was assessed after each socket was worn for 7 weeks. The OPUS Lower-Extremity Functional Status measure is a self-report instrument that assesses functional status in persons who use orthoses and prostheses. It is comprised of 20 items rated on a 5-point rating scale. Responses to items are summed to produce a total score for the measure (0 to 80) with higher scores representing better functional status.	7 weeks
Orthotics andProsthetics Users' Survey (OPUS) Health Related Quality of Life Index Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.	Health Related Quality of life was assessed after each socket was worn for 7 weeks. The OPUS Health Related Quality of Life measure is self-report instrument comprised of 23 items that are evaluated with a 5-point rating scale. Responses to items are summed to produce a total score for the index (0 to 92) with higher scores representing better quality of life.	7 weeks
Orthotics and Prosthetics Users' Survey (OPUS) Satisfaction With Device Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.	Satisfaction with Device was assessed after each socket was worn for 7 weeks. The OPUS Satisfaction with Device measure is a set of 11 items rated on a 5-point rating scale. Responses to items are summed to produce a total score. 9 items were used in this study for a possible score of 9 to 45 with higher scores representing better satisfaction.	7 weeks
5-Times Rapid Sit-to-Stand Test (RSTS) Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.	The 5-Times Rapid-Sit-to-Stand Test was assessed after each socket was worn for 7 weeks. Participants were asked to rise from a chair of standard height five times as fast as possible with their arms folded across their chests. Performance was timed.	7 weeks
Four-Square-Step Test (FSST) Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.	The Four-Square-Step Test was assessed after each socket was worn for 7 weeks. Four sticks were placed flat on the floor in a cross that denoted a square. Participants were asked to complete a stepping sequence as fast as possible. Performance was timed.	7 weeks
T-Test of Agility (T-Test) Between the IC Socket and NU-FlexSIV Socket at 7 Weeks.	The T-Test was assessed after each socket was worn for 7 weeks. Four markers were set out so a "T" could be traced among them. The subject was asked to move as fast as possible between the markers, moving forwards, sideways and backwards. Performance was timed and reported in seconds.	7 weeks

Collaborators and Investigators

• Sponsor: Northwestern University
• Collaborators: United States Department of Defense; Jesse Brown VA Medical Center; Scheck and Siress Prosthetics Orthotics
• Investigators: Principal Investigator: Stefania Fatone, PhD, Northwestern University

Publications and helpful links

General Publications

• Fatone S, Stine R, Caldwell R, Angelico J, Gard SA, Oros M, Major MJ. Comparison of Ischial Containment and Subischial Sockets Effect on Gait Biomechanics in People With Transfemoral Amputation: A Randomized Crossover Trial. Arch Phys Med Rehabil. 2022 Aug;103(8):1515-1523. doi: 10.1016/j.apmr.2022.02.013. Epub 2022 Mar 13.
• Fatone S, Caldwell R, Angelico J, Stine R, Kim KY, Gard S, Oros M. Comparison of Ischial Containment and Subischial Sockets on Comfort, Function, Quality of Life, and Satisfaction With Device in Persons With Unilateral Transfemoral Amputation: A Randomized Crossover Trial. Arch Phys Med Rehabil. 2021 Nov;102(11):2063-2073.e2. doi: 10.1016/j.apmr.2021.05.016. Epub 2021 Jun 29.

Study record dates

Study Major Dates

• Study Start (Actual): April 1, 2016
• Primary Completion (Actual): December 1, 2019
• Study Completion (Actual): December 1, 2019

Study Registration Dates

• First Submitted: February 2, 2016
• First Submitted That Met QC Criteria: February 4, 2016
• First Posted (Estimate): February 9, 2016

Study Record Updates

• Last Update Posted (Actual): June 15, 2021
• Last Update Submitted That Met QC Criteria: May 25, 2021
• Last Verified: May 1, 2021

More Information

Terms related to this study

• Keywords: prosthesis; gait biomechanics; prosthetic socket; transfemoral amputation; socket comfort
• Other Study ID Numbers: W81XWH-15-1-0708

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Yes
• IPD Plan Description: Upon request, the PI will share de-identified data and outcomes. If the requests are excessive, data will be made available via a link on the Northwestern University Prosthetics-Orthotics Center (NUPOC) website.
• IPD Sharing Time Frame: Once results are published.
• IPD Sharing Access Criteria: Upon request, the PI will share de-identified data and outcomes. If the requests are excessive, data will be made available via a link on the Northwestern University Prosthetics-Orthotics Center (NUPOC) website.