Conservative Treatment With Relative Motion Flexion Orthosis for Boutonniere Injuries in Fingers

November 2, 2026 updated by: Lund University Hospital

Conservative Treatment With Relative Motion Flexion (RMF) Orthosis for Boutonniere Injuries

Boutonnière injuries involve damage to the central slip of the extensor tendon over the proximal interphalangeal (PIP) joint (zone III) of the finger. These injuries disrupt the balance of the extensor mechanism, leading to volar displacement of the lateral bands and progressive development of Boutonnière deformity, characterized by PIP joint flexion and distal interphalangeal (DIP) joint hyperextension. Due to the gradual onset and closed nature of the injury, diagnosis is often delayed, and untreated cases may result in joint contractures, reduced range of motion (ROM), pain, and functional limitations.

Treatment is typically conservative and requires prolonged immobilization and splinting, often followed by dynamic orthoses such as Capener splints. However, evidence supporting current treatment strategies is limited and clinical outcomes are variable. Recently, the Relative Motion Flexion (RMF) orthosis has been introduced as an alternative approach aimed at restoring extensor mechanism balance. Existing evidence is limited to small or heterogeneous studies, highlighting the need for further evaluation.

This pilot study aims to assess the feasibility and preliminary effects of RMF orthosis treatment in patients with Boutonnière injuries. The primary objective is to evaluate changes in finger range of motion (ROM) and to estimate variability and within-subject correlations to inform sample size calculations for a future randomized controlled trial. Additional feasibility outcomes include recruitment rate, adherence to treatment, and practicality of measurement procedures.

Secondary objectives include evaluating pain, grip strength, functional hand limitations in daily activities, and patient-reported tolerability and comfort of the orthosis.

The study will be conducted as a prospective longitudinal cohort pilot study with repeated within-subject measurements at baseline, 3 months, and 12 months. A total of 25 adult patients with acute or subacute closed zone III extensor tendon injuries will be recruited consecutively at the Hand Surgery Rehabilitation Unit, Skåne University Hospital, Malmö.

Inclusion criteria include age ≥18 years, positive pencil test, and confirmed central slip injury. Exclusion criteria include open injuries, significant joint contractures (>20°), chronic injuries (>1 year), previous surgery or trauma in the same finger, concomitant fractures or tendon/nerve injuries, inflammatory arthropathies, and severe cognitive or psychiatric conditions or substance abuse.

All participants will receive treatment with an RMF orthosis according to a structured protocol consisting of 6 weeks of continuous use followed by 6 weeks of intermittent daytime and nighttime use. No separate control group will be included; analyses will be based on within-subject comparisons over time.

Primary outcome is ROM measured at the MCP, PIP, and DIP joints using a goniometer. Secondary outcomes include pain (Numeric Rating Scale), grip strength (Jamar dynamometer), hand function (QuickDASH), adherence and tolerability questionnaires, and recruitment rate.

Data will be analyzed using descriptive statistics and nonparametric longitudinal methods, including Friedman tests and Wilcoxon signed-rank tests for paired comparisons across time points.

The study will be conducted in accordance with the Declaration of Helsinki, with ethical approval sought from the Swedish Ethical Review Authority. All participants will provide informed consent, and data will be pseudonymized in accordance with GDPR. The study poses minimal risk, and participants will be monitored throughout treatment with adjustments made as needed.

This pilot study will generate essential data on treatment variability, feasibility, and preliminary outcomes of RMF orthosis use. The results will inform the design of a future randomized controlled trial and may contribute to improved evidence-based management of Boutonnière injuries, potentially leading to better functional outcomes and more efficient rehabilitation strategies.

Study Overview

Status

Status

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

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.

Detailed Description

Boutonnière injuries involve disruption of the central slip of the extensor tendon over the proximal interphalangeal (PIP) joint (zone III) of the finger. This leads to imbalance in the extensor mechanism, with volar displacement of the lateral bands and progressive development of Boutonnière deformity, characterized by PIP flexion and compensatory DIP hyperextension. Due to the often gradual onset and closed injury mechanism, diagnosis is frequently delayed. If untreated, the condition may result in stiffness, joint contractures, pain, reduced range of motion (ROM), and long-term functional impairment.

Current conservative treatment typically consists of prolonged immobilization of the PIP joint in extension, followed by dynamic orthotic management. Although widely used, evidence supporting existing treatment strategies is limited and outcomes are variable. Treatment is often demanding for patients due to prolonged splinting and restricted hand function during rehabilitation.

The Relative Motion Flexion (RMF) orthosis has been introduced as an alternative treatment strategy aimed at restoring balance within the extensor mechanism while allowing greater functional use of the hand during rehabilitation. However, current evidence is limited to small case series, heterogeneous cohorts, and studies with methodological limitations. Further prospective evaluation is therefore needed.

This study is designed as a prospective longitudinal pilot cohort study with repeated within-subject measurements. The primary purpose is to evaluate feasibility and to generate parameters required for planning a future randomized controlled trial, including estimates of variability in range of motion outcomes and within-subject correlations over time.

The study will also explore preliminary effects of RMF orthosis treatment on finger range of motion, as well as secondary outcomes including pain, grip strength, functional hand limitations, and patient-reported tolerability and adherence.

A total of 25 adult patients with acute or subacute closed central slip injuries (zone III) will be recruited consecutively at the Hand Surgery Rehabilitation Unit, Skåne University Hospital, Malmö, Sweden.

Participants will be treated with an RMF orthosis according to a structured rehabilitation protocol consisting of 6 weeks of continuous use followed by 6 weeks of intermittent use during daytime and nighttime. Treatment is delivered as part of routine rehabilitation follow-up, with adjustments made as clinically indicated.

Outcomes will be assessed at baseline, 3 months, and 12 months after treatment initiation. Primary outcome is range of motion (ROM) measured at the MCP, PIP, and DIP joints using a goniometer. Secondary outcomes include pain intensity (Numeric Rating Scale), grip strength (Jamar dynamometer), hand function (QuickDASH), and a study-specific questionnaire assessing adherence and tolerability. Recruitment rate will be recorded as number of eligible patients included per month.

As a pilot study, no control group is included. Analyses will focus on within-subject changes over time and estimation of parameters needed for sample size calculation in a future randomized controlled trial. Data will be analyzed using descriptive statistics and nonparametric longitudinal methods, including Friedman tests and Wilcoxon signed-rank tests for paired comparisons across time points.

The study will be conducted in accordance with the Declaration of Helsinki. Ethical approval will be sought from the Swedish Ethical Review Authority (Etikprövningsmyndigheten). Written informed consent will be obtained from all participants. All data will be pseudonymized and handled in accordance with applicable data protection regulations (GDPR). The study involves minimal risk, and participants will be monitored throughout the rehabilitation period.

This pilot study will provide essential feasibility data and preliminary clinical outcomes for RMF orthosis treatment. The results will inform the design of a future randomized controlled trial and may contribute to improved evidence-based management of Boutonnière injuries, with the potential to enhance functional recovery and optimize rehabilitation strategies.

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 (Estimated)

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.
25

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.
  • Not Applicable

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

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

  • Name: Elisabeth Brogren, PhD
  • Phone Number: +46 40 331185

Study Locations

  • Sweden
    • Skåne County
      • Malmö, Skåne County, Sweden, 205 02
        • Recruiting
        • Skåne University Hospital (Hand Surgery Rehabilitation Unit)
        • 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

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

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • persons with acute and subacute closed injurt to the central slip/extensor tendon zon 3
  • positive pencil test

Exclusion Criteria:

  • open injury or infection
  • joint contracture >20
  • trauma >1 year ago
  • previous trauma or surgery in the same finger
  • simultaneous crush injury
  • concomitant fracture and/or digital nerve injury and/or flexor tendon injury
  • rheumatoid arthritis
  • drug abuse, sever cognitive impairment, or severe psychological disorder

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: Relative Motion Flexion (RMF) orthosis intervention group

Participants in this arm receive treatment with a Relative Motion Flexion (RMF) orthosis as part of a structured rehabilitation protocol. The intervention consists of 6 weeks of continuous orthosis use followed by 6 weeks of intermittent use during daytime and nighttime. No control intervention is used, and outcomes are assessed longitudinally within the same participants over time.
Other: Relative Motion Flexion (RMF) orthosis intervention group

The intervention consists of treatment with a Relative Motion Flexion (RMF) orthosis for patients with Boutonnière injuries of the finger (zone III extensor tendon injuries). The orthosis is applied according to a structured rehabilitation protocol consisting of 6 weeks of continuous wear, followed by 6 weeks of intermittent use during daytime and nighttime. The aim of the intervention is to restore extensor mechanism balance while allowing functional use of the hand during rehabilitation. Participants receive standard follow-up at the hand surgery rehabilitation unit, with adjustments made as clinically indicated.

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
Range Of Motion (ROM)
Time Frame: baseline, 3 months, 12 months

Range of Motion in each joint MCP, PIP, DIP
baseline, 3 months, 12 months
Range of motion (ROM)
Time Frame: baseline, 3 months, 12 months

Active range of motion assessed with a finger goniometer
baseline, 3 months, 12 months

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.
Lund University Hospital

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

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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.
June 30, 2026

Primary Completion (Estimated)

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, 2027

Study Completion (Estimated)

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, 2027

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).
November 2, 2026

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.
November 2, 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.
November 6, 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.
November 6, 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.
November 2, 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.
June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

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.
  • no grant number assigned
  • Region Skåne FoU funding (Other Identifier: no grant number assigned)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

IPD will not be publicly shared. De-identified data may be available upon reasonable request and ethical approval.

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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