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

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

8

Phase

  • 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

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
Intervention / Treatment
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

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

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

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)

March 16, 2023

Primary Completion (Actual)

December 31, 2025

Study Completion (Actual)

December 31, 2025

Study Registration Dates

First Submitted

December 19, 2024

First Submitted That Met QC Criteria

May 26, 2026

First Posted (Actual)

June 2, 2026

Study Record Updates

Last Update Posted (Actual)

June 2, 2026

Last Update Submitted That Met QC Criteria

May 26, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID 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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