Influence of Prosthetic Foot Stiffness on Transtibial Osseointegrated Bone-Anchored Limb Outcomes (TBAL)

April 20, 2026 updated by: University of Colorado, Denver
A clinical trial utilizing cross-over study design in which individuals with transtibial amputation using either a bone-anchored limb or standard socket prosthesis will perform activities of daily living with varying prosthetic foot stiffness categories to complete the following 4 Specific Aims: 1) Determine the influence of prosthetic foot stiffness on dynamic bone-implant loading, 2) Determine how prosthetic foot stiffness influences function, pain, and multi-joint biomechanics outcomes, 3) Establish how prosthetic foot stiffness influences osseoperception and fall risk, and 4) Establish target ranges of optimal foot stiffness based on the sensitivity biomechanical outcomes to variability in foot stiffness.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This will be a clinical trial with two groups (individuals with a unilateral transtibial amputation using either an osseointegrated bone-anchored limb or socket prosthesis that will implement a cross-over design. The objective of this clinical trial is to determine how changes in prosthetic foot stiffness influence clinical and biomechanical outcomes in patients with transtibial osseointegrated bone-anchored limbs compared to patients with transtibial amputation using a standard socket-suspended prosthesis. Although proper loading between the bone and implant is pivotal to promote and maintain osseointegration, which is required for physiological loading and thus positive outcomes, evidence surrounding the role of how prosthetic componentry influences force transmission and functional outcomes in this population currently does not exist. The findings of this clinical trial will address a critical knowledge gap pertaining to the role of componentry on multi-loading domain outcomes. Outcomes will be assessed in each participant in the same three conditions: one with their clinical prescribed prosthetic foot, one with a soft prosthetic foot (-2 stiffness categories less than prescribed), and one with a stiff prosthetic foot (+2 stiffness categories more than prescribed). This data will be used to test/develop the following aims: 1) Does foot stiffness change loading between the bone and implant during activities of daily living? 2) Does foot stiffness influence measures of function, pain, and biomechanics in patients with transtibial osseointegrated bone-anchored limbs differently than a socket prosthesis? 3) Does foot stiffness influence sensitivity, balance, and fall risk in patients using an osseointegrated bone-anchored limb different than a socket prosthesis? and 4) (exploratory) develop an optimization platform using computer models to determine the optimal foot stiffness that maximizes joint loading symmetry and minimizes metabolic cost.

Study Type

Interventional

Enrollment (Estimated)

60

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • United States
    • Colorado
      • Aurora, Colorado, United States, 80045-2559
        • Recruiting
        • University of Colorado, Anschutz Medical Campus
        • Contact:
        • Principal Investigator:
          • Brecca Gaffney, PhD
        • Principal Investigator:
          • Jason Stoneback, MD
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Unilateral transtibial amputation due to traumatic, congenital, or cancer-related causes
  • > 12-months bone-anchored limb implantation surgery (Bone Anchored Limb group)
  • > 12-months limb amputation (Socket Control group)
  • Non-vascular amputation etiology
  • Low profile prosthetic foot (nominal)
  • Can walk unassisted for 5-minutes
  • > 18 years old

Exclusion Criteria:

  • Major amputation on contralateral limb
  • Vascular amputation etiology
  • Neurologic pathology that impairs coordination/balance
  • Regular assistive device use required for community ambulation
  • Inflammatory diseases or diabetes
  • Pregnancy or breastfeeding

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Two prosthetic foot stiffness categories stiffer than the as-prescribed prosthetic foot stiffness
A prosthetic foot that is two prosthetic foot stiffness categories stiffer than the stiffness of the as-prescribed prosthetic foot. The prosthetic foot type, including the manufacturer and length, will remain the same as the nominal (as-currently prescribed) foot.
Device: A prosthetic foot that is two prosthetic foot stiffness categories softer than the stiffness of the as-prescribed prosthetic foot
Each participant will complete a motion capture collection, tests of physical function, and sensory tests in a prosthetic foot that is two categories softer than their currently prescribed prosthetic foot.
Active Comparator: Two prosthetic foot stiffness categories softer than the as-prescribed prosthetic foot stiffness
A prosthetic foot that is two prosthetic foot stiffness categories softer than the stiffness of the as-prescribed prosthetic foot. The prosthetic foot type, including the manufacturer and length, will remain the same as the nominal foot.
Device: A prosthetic foot that is two prosthetic foot stiffness categories stiffer than the stiffness of the as-prescribed prosthetic foot
Each participant will complete a motion capture collection, tests of physical function, and sensory tests in a prosthetic foot that is two categories stiffer than their currently prescribed prosthetic foot.
Active Comparator: As-prescribed prosthetic foot stiffness
The prosthetic foot that is currently prescribed and used by each participant daily.
Device: As-prescribed prosthetic foot stiffness
Each participant will complete a motion capture collection, tests of physical function, and sensory tests in their currently prescribed prosthetic foot.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Bone-Implant Stress/Strain Impulse during Decline Walking (internal)
Time Frame: Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Stress/strain impulse at the bone-implant interface (area under time series curve) will be calculated during the stance period of the decline walk (-5 degrees). Subject-specific finite element models will be developed for each bone-anchored limb participant to calculate this outcome. This will be done by including each participant's movement patterns, muscle forces, joint forces, bone geometry and bone health. Movement patterns, muscle forces, and joint loading will be calculated from musculoskeletal modeling using whole-body motion data collected from 70 wearable reflective markers (Vicon, Centennial, CO), ground reaction forces simultaneously collected from an instrumented treadmill (Bertec, Columbus, OH). Bone geometry and healthy will be determined from quantitative computed tomography bone scans.
Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Bone-Implant Dynamic Stress/Strain Impulse (internal)
Time Frame: Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Stress/strain impulse at the bone-implant interface (area under time series curve) will be calculated for each bone-anchored limb participant using motion and force data collected during the stance period of treadmill walking at level and incline (+5 degree) angles.
Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Bone Dynamic Stress/Strain Impulse (internal)
Time Frame: Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Stress/strain impulse for the amputated tibia bone (area under time series curve) will be calculated for each bone-anchored limb participant using motion and force data collected during the stance period of treadmill walking at level, incline (+5 degree), and decline (-5 degree) angles.
Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Implant Dynamic Stress/Strain Impulse (internal)
Time Frame: Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Stress impulse for the prosthesis implant (area under time series curve) will be calculated for each bone-anchored limb participant using motion and force data collected during the stance period of treadmill walking at level, incline (+5 degree), and decline (-5 degree) angles.
Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Prosthesis Force Impulse (external abutment)
Time Frame: Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Force impulse in the vertical direction (area under the time series curve) will be calculated for all study participants using motion and force data collected from the triaxial load sensor in the prosthesis (iPECSTM) during the stance period of treadmill walking at level, incline (+5 degree), and decline (-5 degree) angles.
Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Sensory Threshold
Time Frame: Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
With each foot (stiff, nominal (as-prescribed), soft), participants will stand on a platform with the prosthetic equivalent of the head of the third metatarsal in contact with an extension pin delivering a vibration. While wearing noise-reducing headphones, three different vibration frequencies will be tested in a randomized order: 8, 32, and 125 Hz. At each frequency, custom software will increase and decrease the vibrational amplitude at a rate of 0.2 dB/s. Using an integrated push button, the participant will indicate when sensation is felt (during increasing amplitude) or when sensation is lost (during decreasing amplitude), which will be the sensory threshold.
Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Postural Sway
Time Frame: Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Postural sway will be quantified during quiet standing with eyes open and eyes closed condition. Using the center of pressure measured from the force platform under both feet, path length and 95% confidence ellipse area will be calculated.
Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Reactive Postural Control Time
Time Frame: Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Reaction times during stepping responses to rapid treadmill belt perturbations will be measured using a force-instrumented treadmill (Bertec, Columbus, OH, USA).
Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Whole-Body Angular Momentum
Time Frame: Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Peak-to-peak whole-body angular momentum will be calculated as a measure of dynamic balance during each dynamic functional activity (level/incline/decline walking and stair ascent/descent) and treadmill perturbation.
Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Self-Selected Gait Speed
Time Frame: Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Gait velocity will be calculated using the time it takes each participant to walk 5-meters at their preferred, self-selected pace, averaged over three trials.
Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
L-Test Time
Time Frame: Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
The L-test will be quantified as the time it takes to stand up from a chair, walk 3-meters, complete a 90° left turn, walk 7-meters, completed a 180° turn, walk back on the same path, turn, and sit down.
Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Acceptability of Intervention Measure
Time Frame: Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
The Acceptability of Intervention Measure is a 4-item, Likert-scale (5 point) self-report questionnaire assessing participant acceptability of the intervention (prosthetic foot type). Final scores range from 1 to 5 points, as the mean of the four items, with higher scores indicating greater acceptability.
Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Prosthetic Limb Users Survey of Mobility
Time Frame: Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
The Prosthetic Limb Users Survey of Mobility is a 12-item, Likert scale (5 point) self-report questionnaire assessing participant mobility when using a prosthesis. Final scores range from 12 to 60 points with higher scores indicating greater mobility.
Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Activities-Specific Balance Confidence Scale
Time Frame: Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
The Activities-Specific Balance Confidence Scale is a 16-item, 0-100 scale, self-reported questionnaire assessing participant balance confidence. Final scores range from 0% (no confidence in balance) to 100% (complete confidence in balance).
Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Joint Reaction Force
Time Frame: Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks
Bilateral hip and knee joint reaction forces (normalized to body weight) will be calculated during treadmill walking using a combination of motion-capture data and subject-specific musculoskeletal models.
Three laboratory visits, each lasting approximately 4 hours, spanning across approximately 6-8 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Colorado, Denver

Collaborators

Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 25, 2025

Primary Completion (Estimated)

May 31, 2030

Study Completion (Estimated)

May 31, 2030

Study Registration Dates

First Submitted

October 22, 2025

First Submitted That Met QC Criteria

November 23, 2025

First Posted (Actual)

December 4, 2025

Study Record Updates

Last Update Posted (Actual)

April 21, 2026

Last Update Submitted That Met QC Criteria

April 20, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • 25-0854
  • 1R01HD119003-01 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

The investigators will publish the trial results data on the ClinicalTrials.gov website, on which the clinical trial will be registered. Sharing of data will include the potential of sharing raw data generated from all clinical assessments under a data-sharing agreement.

IPD Sharing Time Frame

The investigators will publish the trial results within one year of testing the final participant.

IPD Sharing Access Criteria

User registration will be required to access/download any data and will require agreement to conditions of use in accordance with CDMRP Policy on Sharing Data and Research Resources.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • ICF

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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