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Evaluation of a Modified Running-specific Prosthetic Foot

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ClinicalTrials.gov Identifier: NCT02440711
Recruitment Status : Active, not recruiting
First Posted : May 12, 2015
Last Update Posted : April 27, 2018
Sponsor:
Information provided by (Responsible Party):
Brian Hafner, University of Washington

Brief Summary:
The goal of this study is to evaluate endurance, walking performance, mobility, and perceived exertion of transtibial prosthesis users (i.e., study participants) walking with a conventional energy storing prosthetic foot (ESF) and a novel modified running-specific prosthesis (mRSF). A randomized cross-over study will be conducted to determine if the mRSF provides superior performance to the ESF, which is commonly prescribed to most active individuals with lower limb amputation.

Condition or disease Intervention/treatment Phase
Transtibial Amputation Device: Energy storing foot (ESF) Device: Modified running specific foot (mRSF) Not Applicable

Detailed Description:

Amputation of a limb is a life-altering event with profound physical, psychological, and social implications. To address their functional, vocational, and recreational needs, people with lower limb amputation (LLA) are often provided with a prosthesis or artificial leg. While use of a prosthesis can allow an individual to achieve a basic level of functional mobility, absence of an anatomical foot and ankle still impairs their physical performance. As a result, people with LLA regularly exhibit decreased walking speeds, diminished endurance, and restricted ability to participate in desired life situations.

Over the past three decades, increasingly sophisticated prosthetic foot designs have been developed by the prosthetics industry to replace amputated structures in the leg. Contemporary, energy storing feet (ESF) employ advanced materials and unique geometric designs to improve walking performance and endurance of their users. Although prosthetic limbs with ESF allow people with LLA the potential to return to an active lifestyle, even the most advanced ESF do not significantly reduce the increased energy demands required for walking when compared to conventional prosthetic feet.

Commercially-available running-specific feet (RSF) like the Össur Cheetah (Össur, Reykjavik, Iceland) allow people with LLA to participate in athletic activities and sporting events. RSF provide significantly enhanced performance, compared to traditional ESF, by extending the length and increasing the stiffness of the prosthetic keel (forefoot). RSF also do not include a heel, as they are used only for running activities. Although transtibial runners with RSF exhibit endurance levels similar to non-amputees, the RSF design does not allow the biomechanical movements or provide the stability needed to use the foot for walking (over level or uneven terrain).

A novel modified running-specific foot (mRSF) has been developed to integrate the performance of a RSF with the utility of an ESF. The mRSF combines the running keel (forefoot) of a RSF with the walking heel of a ESF. The mRSF can then be used for walking, running, and other routine daily activities. Preliminary feedback on the mRSF suggests that users experience improved overall function and high satisfaction with the device. However, empirical evidence is needed to support prescription of this prosthetic foot at other clinical facilities.

The goal of this study is therefore to evaluate endurance, walking performance, mobility, and perceived exertion of transtibial prosthesis users (i.e., study participants) walking with a conventional ESF and the mRSF. Results will be compared to determine if the mRSF provides superior performance to the ESF, which is commonly prescribed to most active individuals with LLA.


Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 30 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Endurance, Energy Expenditure, Perceived Function, and Satisfaction of Persons With Transtibial Limb Loss Using a Running‐Specific Prosthesis Modified for Walking
Study Start Date : May 2015
Estimated Primary Completion Date : April 2018
Estimated Study Completion Date : April 2018

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Foot Health

Arm Intervention/treatment
Experimental: mRSF-ESF
Study participants in Arm 1 will first receive the Modified running specific foot (mRSF) and then the Energy storing foot (ESF). Outcomes will be assessed (in each condition) after 1 month of use. Order of interventions will be randomly assigned.
Device: Energy storing foot (ESF)
A commercially-available energy storing prosthetic foot
Other Name: Ossur Vari-flex

Device: Modified running specific foot (mRSF)
A running specific prosthetic foot customized for both running and walking activities
Other Name: Ossur Cheetah (modified); Ossur Xplore

Experimental: ESF-mRSF
Study participants in Arm 2 will first receive the Energy storing foot (ESF) and then the Modified running specific foot (mRSF). Outcomes will be assessed (in each condition) after 1 month of use. Order of interventions will be randomly assigned.
Device: Energy storing foot (ESF)
A commercially-available energy storing prosthetic foot
Other Name: Ossur Vari-flex

Device: Modified running specific foot (mRSF)
A running specific prosthetic foot customized for both running and walking activities
Other Name: Ossur Cheetah (modified); Ossur Xplore




Primary Outcome Measures :
  1. Metabolic Oxygen Consumption (VO2) [ Time Frame: Subjects are tested after using each foot in their prosthesis for 1 month ]
    VO2 is collected as subjects walk on a treadmill at self selected fast, normal, and slow speeds. Subjects walk for 6 minutes at each speed (and in each experimental condition). VO2 at steady state (last 1 minute of testing) will be normalized to the subject's body weight. Gross and net (relative to resting VO2) energy cost of walking (ECW) will be calculated.

  2. Six minute walk test [ Time Frame: Subjects are tested after using each foot in their prosthesis for 1 month ]
    Subjects will be asked to walk as far as possible in 6 minutes. Subjects will walk around cones placed 30m apart in a level hallway. Total distance walked in 6 minutes will be recorded.

  3. Borg rating of perceived exertion (CR100) [ Time Frame: Subjects are tested after using each foot in their prosthesis for 1 month ]
    Subjects will be asked to self-report their level of perceived exertion after completing the 6-minute walk test. Subjects will be shown the Borg CR100 rating scale and asked to identify their level of exertion.


Secondary Outcome Measures :
  1. Prosthetic Limb Users Survey of Mobility (PLUS-M) [ Time Frame: Subjects are evalauted after using each foot in their prosthesis for 1 month ]
    The PLUS-M is a self-report instrument designed to evaluate respondent's prosthetic mobility. Subjects will be administered the computer adaptive test version of the PLUS-M on an iPad tablet.

  2. Patient Reported Outcome Measurement Information System - Fatigue (PROMIS-Fatigue) [ Time Frame: Subjects are evalauted after using each foot in their prosthesis for 1 month ]
    The PROMIS-Fatigue is a self-report instrument designed to evaluate respondent's symptoms and effects of fatigue. Subjects will be administered the computer adaptive test version of the PROMIS-Fatigue on an iPad tablet.

  3. Activities-Specific Balance Confidence Scale (ABC) [ Time Frame: Subjects are evalauted after using each foot in their prosthesis for 1 month ]
    The ABC is a self-report instrument designed to evaluate respondent's confidence in performing normal daily activities. Subjects will be administered an electronic version of the ABC on an iPad tablet.

  4. Trinity Amputation Prosthesis Experience Scales, Revised (TAPES-R) [ Time Frame: Subjects are evalauted after using each foot in their prosthesis for 1 month ]
    The TAPES-R is a self-report instrument designed to evaluate respondent's activity restrictions and satisfaction with a prosthesis. Subjects will be administered an electronic version of the TAPES-R on an iPad tablet.



Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • unilateral or bilateral, transtibial (below-knee) amputation from non-dysvascular causes
  • Medicare functional classification level (K-level) 3 or higher (unlimited community ambulatory)
  • prosthetic user for > 1 year
  • scheduled to receive a mRSF prosthesis
  • able and willing to participate in the study protocol (e.g., treadmill walking, overground walking, respond to survey questions, able to read and write English)

Exclusion Criteria:

  • contralateral lower or upper limb involvement
  • any health condition that would limit participation in the study procedures (e.g., skin breakdown, heart disease)

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02440711


Locations
United States, Washington
University of Washington
Seattle, Washington, United States, 98195
Sponsors and Collaborators
University of Washington
Investigators
Principal Investigator: Brian Hafner, PhD University of Washington

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Brian Hafner, Associate Professor, University of Washington
ClinicalTrials.gov Identifier: NCT02440711     History of Changes
Other Study ID Numbers: 49150
First Posted: May 12, 2015    Key Record Dates
Last Update Posted: April 27, 2018
Last Verified: April 2018