Sub-Ischial Socket for Transfemoral Amputation and Lower Mobility

NCT ID: NCT05662982

Last Updated: 2025-12-15

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

84 participants

Study Classification

INTERVENTIONAL

Study Start Date

2023-03-01

Study Completion Date

2025-11-30

Brief Summary

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The objective of this trial is to assess use and benefits of the subischial socket for persons with transfemoral amputation and lower mobility levels. Specifically, the investigators will evaluate whether the subischial socket improves comfort, socket wear time, mobility, participation, quality of life and satisfaction with device than the standard-of-care ischial containment socket.

Detailed Description

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Prosthetic sockets that are currently used by persons with above-the-knee amputation (AKA) fit intimately with the thigh and pelvis, limiting hip motion and causing discomfort. Socket comfort while standing and sitting is of great importance to persons with lower limb amputation. Yet discomfort while sitting has been reported in 44% of persons with AKA. In those with AKA who are more sedentary, clinical observation indicates that socket discomfort in sitting results in less prosthesis wear time and less mobility with the prosthesis. Based on these observations, the investigators propose that improving socket comfort in persons with AKA who have lower mobility will increase the time spent wearing the socket, which will in turn increase mobility, and in turn again improve satisfaction with the prosthesis and overall quality-of-life. A new prosthetic socket design, the sub-ischial socket, which eliminates contact with the pelvis, has been developed with the intent of improving comfort and hip motion in people with AKA. In particular, sitting comfort has been highlighted as an advantage of this new socket design by early users. Therefore, the objective of this project is to assess use and benefits of the sub-ischial socket for persons with AKA and lower mobility levels. The investigators will evaluate whether the sub-ischial socket is more comfortable, improves prosthesis wear time, mobility, participation in society, satisfaction with device, skin-related quality-of-life, and health-related quality of life compared to the current standard-of-care socket design in persons with AKA and lower mobility levels. If a participant is eligible and enrolled into this study, participation would last about 10 months and would involve up to 8 in-person visits (for individuals receiving a new sub-ischial socket). Individuals receiving a new sub-ischial socket will also be asked to wear a step counter and temperature sensor and complete 11 remote survey assessments spread over the 10-month period of the study. Data will also be collected from a reference group of participants with transfemoral amputation and lower mobility levels who will not receive a sub-ischial socket. These participants will be assessed while wearing their clinically-provided, standard-of-care ischial containment socket. These participants will complete 8 remote survey assessments over a 10-month period.

Conditions

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Transfemoral Amputation

Study Design

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Allocation Method

NON_RANDOMIZED

Intervention Model

PARALLEL

Two independent groups will be assessed longitudinally over 40 weeks: one group will be assessed using only the standard of care ischial containment socket and the other group will receive the subischial socket.
Primary Study Purpose

TREATMENT

Blinding Strategy

NONE

Study Groups

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Intervention Group

Participants will be assessed for 12 weeks in their usual ischial containment socket before receiving a subischial socket to be worn and assessed for 24 weeks.

Group Type EXPERIMENTAL

Northwestern University Flexible Subischial Suction Socket (NU-FlexSIS)

Intervention Type DEVICE

A custom-made prosthetic socket for transfemoral amputation that consists of proximal trimlines that do not interact with the pelvis.

Reference Group

Participants will be assessed for 40 weeks in their usual ischial containment socket. No intervention will be provided.

Group Type NO_INTERVENTION

No interventions assigned to this group

Interventions

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Northwestern University Flexible Subischial Suction Socket (NU-FlexSIS)

A custom-made prosthetic socket for transfemoral amputation that consists of proximal trimlines that do not interact with the pelvis.

Intervention Type DEVICE

Eligibility Criteria

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Inclusion Criteria

1. Speak and read English;
2. Provision of signed and dated informed consent form;
3. Stated willingness to comply with all study procedures and availability for the duration of the study;
4. All sexes and genders age 18 years and older;
5. Have a unilateral transfemoral or knee disarticulation amputation and have used a prosthesis for 1 year or more;
6. Be classified by their prosthetist as being a Medicare Functional Classification Level of K2 (limited community ambulator);
7. Have never worn a sub-ischial socket;
8. Current IC socket and prosthesis must be well fitting and maintained; current socket must have pelvic weightbearing and/or containment;
9. Participant has no plans to change the knee or foot in the next 10 months;
10. Willingness to adhere to the monitoring and new socket regimen;
11. Have sufficient upper limb function to don liner and change sensors;
12. Access to necessary resources for participating in the study (i.e., computer, smartphone, internet access, telephone):
13. Be a Veteran (VA site only).

Exclusion Criteria

1. Have a femoral length \<5 inches;
2. Have a known silicone allergy;
3. Are unable to don or tolerate wearing a compressive liner;
4. Loss of metatarsal heads on contralateral limb;
5. Active malignancy;
6. Pregnancy;
7. Polytrauma that affects functional ability beyond that of a unilateral transfemoral amputation.
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Congressionally Directed Medical Research Programs

FED

Sponsor Role collaborator

University of Washington

OTHER

Sponsor Role lead

Responsible Party

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Stefania Fatone

Professor, School of Medicine

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Stefania Fatone, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Washington

Locations

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Minneapolis VA Health Care System

Minneapolis, Minnesota, United States

Site Status

Hanger Institute for Clinical Research and Education

Houston, Texas, United States

Site Status

University of Washington

Seattle, Washington, United States

Site Status

Countries

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United States

References

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Fatone S, Caldwell R. Northwestern University Flexible Subischial Vacuum Socket for persons with transfemoral amputation-Part 1: Description of technique. Prosthet Orthot Int. 2017 Jun;41(3):237-245. doi: 10.1177/0309364616685229. Epub 2017 Jan 17.

Reference Type BACKGROUND
PMID: 28094686 (View on PubMed)

Caldwell R, Fatone S. Technique modifications for a suction suspension version of the Northwestern University Flexible Sub-Ischial Vacuum socket: The Northwestern University Flexible Sub-Ischial Suction socket. Prosthet Orthot Int. 2019 Apr;43(2):233-239. doi: 10.1177/0309364618798869. Epub 2018 Sep 17.

Reference Type BACKGROUND
PMID: 30223715 (View on PubMed)

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.

Reference Type BACKGROUND
PMID: 34214499 (View on PubMed)

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.

Reference Type BACKGROUND
PMID: 35296398 (View on PubMed)

Provided Documents

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Document Type: Informed Consent Form: UW-Hanger Intervention Group ICF 2023-07-27

View Document

Document Type: Informed Consent Form: MVAHCS Intervention Group ICF 2024-07-25

View Document

Document Type: Informed Consent Form: UW-Hanger Reference Group ICF 2023-08-31

View Document

Document Type: Informed Consent Form: UW Reference Group ICF 2024-03-01

View Document

Other Identifiers

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CDMRP-E03034.1a

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

CDMRP-E03034.1b

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

STUDY00015284

Identifier Type: -

Identifier Source: org_study_id

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