Anterior Heel Wedge to Treat Flexion Contracture After Total Knee Arthroplasty

May 26, 2026 updated by: Abbey Thomas, PhD, University of North Carolina, Charlotte

Efficacy of Anterior Heel Wedge at Reducing Knee Flexion Contracture After Total Knee Arthroplasty: A Pilot Investigation

Total knee arthroplasty (TKA) remains the only treatment for end-stage knee osteoarthritis, whereby the diseased ends of the bones comprising the knee joint are removed and replaced with prosthetic joint components. Approximately 500,000 of these procedures are performed annually in the United States. Despite an otherwise successful procedure and post-operative rehabilitation process, about 5% of all individuals will develop a flexion contracture after TKA. Flexion contracture limits the knee joint range of motion, which has negative impacts on activities of daily living and health-related quality of life. Standard of care treatment for resolving flexion contracture requires more surgery or, at minimum, more exposure to anesthesia to manipulate the joint and improve range of motion. The investigators have developed a non-invasive means for resolving flexion contracture, The investigators propose fixing a wedge to the sole of the patient's shoe such that the taller end of the wedge is located near the toes and the shorter end is closer to the heel. Biomechanically, this forces the individual to make ground contact during walking closer to the heel rather than the toes (which is typically observed in patients with flexion contracture). By forcing ground contact closer to the heel, patients gradually force their knee to extend (straighten) over time and resolve the flexion contracture. The aim of this pilot investigation is to test the hypothesis that the anterior wedge worn on the shoe during all walking activities for 4 weeks will reduce the severity of the flexion contracture in patients after TKA.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
8

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Early 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 Locations

  • United States
    • North Carolina
      • Charlotte, North Carolina, United States, 28269
        • UNC Charlotte

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • over the age of 18 years
  • underwent primary, unilateral TKA and approved for participation by surgeon
  • present with flexion contracture in the operative limb (5 degrees or greater at least 3 months after surgery)
  • body mass index <40kg/m^2

Exclusion Criteria:

  • underwent revision TKA
  • underwent bilateral TKA
  • require use of assistive device to walk
  • inability to consistently comprehend and repeat back directions, including for reasons of not understanding/speaking English
  • current smoker

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: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Orthotic
Participants enrolled in this arm wear an anterior heel wedge, in the form of a shoe orthotic, to improve walking and reduce knee flexion contracture. The wedge is worn continuously on the shoe for 1 month.
Device: Anterior heel wedge
A continuously-worn shoe anterior heel wedge that fits on the under surface of the shoe just under the toe box. When worn during walking, the anterior heel wedge may help to increase knee joint range of motion and reduce knee flexion contracture in patients after total knee arthroplasty.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Gait biomechanics
Time Frame: From enrollment to the end of treatment at 4 weeks
Participants will walk over level ground at a self-selected pace and one equivalent to average older adult walking speed.
From enrollment to the end of treatment at 4 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Patient-reported outcomes
Time Frame: From baseline to the end of the intervention at 4 weeks
Participants will complete the Knee Osteoarthritis Outcomes Survey (0-100, higher scores are better).
From baseline to the end of the intervention at 4 weeks
Patient-reported outcomes
Time Frame: From baseline to the end of the intervention at 4 weeks
Participants will complete a Global rating of change (-7 to 7, higher scores indicate more positive changes).
From baseline to the end of the intervention at 4 weeks
Patient-reported outcomes
Time Frame: From baseline to the end of the intervention at 4 weeks
Participants will complete the VR-12 (0-100 with higher scores indicating more optimal physical and mental well-being) .
From baseline to the end of the intervention at 4 weeks
Patient-reported outcomes
Time Frame: From baseline to the end of the intervention at 4 weeks
Participants will complete the International Physical Activity Questionnaire- Short Form (0- no max possible, higher scores indicate greater levels of physical activity).
From baseline to the end of the intervention at 4 weeks

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of North Carolina, Charlotte

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 16, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 19, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 26, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 2, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 2, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 26, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 22-1206

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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