A Comparison Between Ischial-Containment and Sub-Ischial Prosthetic Sockets to Determine Their Effects on Secondary Health Conditions

Long-term above-knee prosthesis users are at an increased risk of developing secondary musculoskeletal conditions compared to the general able-bodied population. One secondary physical concern is low back pain (LBP), for which the development is not entirely understood, but in above-knee prosthesis users it is believed to relate to asymmetries and compensations that are typically demonstrated and required to stand and walk. Understanding spinal motion and compensations will enhance our knowledge of the factors contributing to LBP, and possibly lead to the development of new prosthetic and therapeutic interventions to prevent or alleviate LBP, thereby improving mobility and quality of life for prosthesis users.

Study Overview

• Status: Not yet recruiting
• Conditions: Unilateral Transfemoral Amputation

Detailed Description

The purpose of this study is to investigate and compare the effects of the standard ischial containment (IC) socket to a sub-ischial (SI) socket design on the spinal and pelvic motions and leg length (LLD) discrepancies of transfemoral prosthesis users. Data will be collected from 2 groups of transfemoral prosthesis users (15 SI socket wearers and 15 IC socket wearers) and a group of 15 able-bodied (AB) control participants. Gait and standing analyses will be conducted on each participant using a marker based motion capture system. Prosthesis users will wear their own conventional sockets for the gait and standing analyses. Kinematic and kinetic data will be analyzed for differences between the 2 groups of socket wearers and will also be compared to the control group.

The specific aims and hypotheses of this project are:

Aim 1: To measure dynamic leg length and kinematics of the pelvis and spinal segments in unilateral, transfemoral prosthesis users during gait. Quantitative motion analyses will be performed on two groups of 15 research participants with lower limb amputation using 2 different socket designs (IC and SI) walking over level ground at three self-selected walking speeds (normal, moderately fast, fastest). Data will be compared between socket type and to an AB control group. Hypothesis 1a-IC socket wearers will have a greater anterior pelvic tilt compared to SI socket wearers and AB controls, and they will exhibit considerably greater rotations of the pelvis and spinal segments during walking. Hypothesis 1b-The EMG activity of the lumbar erector spinae for SI socket users will better approximate the patterns of AB controls as compared to IC socket wearers. Hypothesis 1c-The dynamic LLD will be greater for IC socket users compared to SI socket wearers and AB controls.

Aim 2: To measure pelvic orientation and static leg length in unilateral, transfemoral prosthesis users during standing. A multi-segment model of the spine and pelvis will be used to determine neutral spinal, pelvis, and prosthetic alignment during standing for the research and AB control participants. Hypothesis 2a-IC socket wearers will demonstrate greater anterior pelvic tilt during standing compared to SI socket wearers and control participants. Hypothesis 2b-The prosthetic and sound leg lengths for both prosthesis user groups will be within 1.0 cm of each other during standing.

Aim 3: To estimate joint contact forces in the legs and lower back of unilateral, transfemoral prosthesis users and controls during gait. Computational musculoskeletal simulations will be used to comprehensively evaluate the data from Aim 1 to compare the lumbar joint loads between IC and SI socket wearers. Hypothesis 3-IC socket wearers will exhibit greater lumbar joint loads than SI socket wearers.

• Study Type: Observational
• Enrollment (Estimated): 45

Contacts and Locations

• Study Contact: Name: Rebecca Stine, MS; Phone Number: (312) 503-5726; Email: rebecca.stine@va.gov
• Study Contact Backup: Name: Steven A Gard, PhD; Phone Number: (312) 503-5718; Email: steven.gard@va.gov

Study Locations

• United States
  • Illinois
    • Chicago, Illinois, United States, 60612
      • Jesse Brown VA Medical Center, Chicago, IL
      • Contact: Rebecca Stine, MS; Phone Number: (312) 503-5726; Email: rebecca.stine@va.gov
      • Contact: Steven A Gard, PhD; Phone Number: (312) 503-5718; Email: steven.gard@va.gov
      • Principal Investigator: Rebecca Stine, MS

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Thirty unilateral transfemoral prosthesis users (15 with an ischial containment socket and 15 with a sub-ischial socket) and 15 able-bodied control participants.

Description

Inclusion Criteria:

For all participants:

• Ability to complete the experimental protocol without undue fatigue or health risks
• Low Back Pain scale assessment (0-10) less than 4 (activities of daily living or quality of life not impacted)

In addition for persons with lower limb amputation:

• Prosthesis user for a minimum of 2 years with their current socket design
• Good fit with either an ischial containment (IC) or sub-ischial (SI) socket
• Good skin integrity on their residual limb upon visual inspection
• Does not require the use of assistive devices to walk

Exclusion Criteria:

• Previously diagnosed with a spine condition (e.g., pinched nerve, bulging disc, etc.)
• Previously diagnosed with an orthopedic or neuromuscular condition that may affect walking or balance (e.g., ankle fusion, Parkinson's disease, stroke, etc.)

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort
Ischial Containment Socket user; Person with unilateral transfemoral amputation wearing an ischial containment socket
Sub-Ischial Socket user; Person with unilateral transfemoral amputation wearing a sub-ischial socket
Able-bodied control; Person without an amputation

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Anterior Pelvic Tilt Angle Between the IC Socket wearers and the SI Socket wearers/Able-Bodied Controls	Anterior Pelvic Tilt will be calculated for all participants during the walking and standing trials. Participants will walk along a 10 meter walkway at varying speeds. Quantitative motion analysis using a marker based motion measurement system will be used to calculate anterior pelvic tilt.	To be measured on day 1 of the single study visit, within an estimated 3-hour timeframe

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Electromyography (EMG) Activity of the Lumbar Erector Spinae Between the IC Socket wearers and the SI Socket wearers/Able-bodied Controls	EMG activity will be assessed using surface electrodes attached bilaterally to the erector spinae at and below T12/L1 and on the external oblique muscle. Data will be collected during the quantitative motion analysis.	To be measured on day 1 of the single study visit, within an estimated 3-hour timeframe
Lumbar Flexion Between the IC Socket wearers and the SI Socket wearers/Able-bodied Controls	Lumbar flexion will be calculated for all participants during the walking and standing trials. Participants will walk along a 10 meter walkway at varying speeds. Quantitative motion analysis using a marker based motion measurement system will be used to calculate anterior pelvic tilt.	To be measured on day 1 of the single study visit, within an estimated 3-hour timeframe
Hip Joint Range of Motion (ROM) between the IC Socket wearers and the SI Socket wearers/Able-bodied Controls	Hip Joint ROM will be calculated for all participants during the walking trials. Participants will walk along a 10 meter walkway at varying speeds. Quantitative motion analysis using a marker based motion measurement system will be used to calculate hip joint ROM.	To be measured on day 1 of the single study visit, within an estimated 3-hour timeframe
Dynamic Leg Length Discrepancy (LLD) Between the IC Socket wearers and the SI Socket wearers/Able-bodied Controls	Dynamic LLD will be calculated for all participants during the walking trials. Participants will walk along a 10 meter walkway at varying speeds. Quantitative motion analysis using a marker based motion measurement system will be used to calculated dynamic LLD.	To be measured on day 1 of the single study visit, within an estimated 3-hour timeframe
Peak Lumbar Joint Loading Between the IC Socket wearers and the SI Socket wearers/Able-bodied Controls	Lumbar joint loading during walking will be analyzed by performing musculoskeletal modeling simulations using data collected during the quantitative motion analysis.	To be measured on day 1 of the single study visit, within an estimated 3-hour timeframe

Collaborators and Investigators

• Sponsor: VA Office of Research and Development
• Investigators: Principal Investigator: Rebecca Stine, MS, Jesse Brown VA Medical Center, Chicago, IL

Study record dates

Study Major Dates

• Study Start (Estimated): January 1, 2027
• Primary Completion (Estimated): July 1, 2030
• Study Completion (Estimated): December 31, 2030

Study Registration Dates

• First Submitted: August 4, 2026
• First Submitted That Met QC Criteria: August 12, 2026
• First Posted (Actual): August 17, 2026

Study Record Updates

• Last Update Posted (Actual): August 17, 2026
• Last Update Submitted That Met QC Criteria: August 12, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Keywords: low back pain; transfemoral amputation; prosthetic socket design
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Back Pain; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Low Back Pain
• Other Study ID Numbers: RRD2-014-25W

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

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