Metacarpal Shaft FracturesCARBO CARBONNCT07521943
The CARBO CARBON Study
An observational study of Metacarpal Shaft Fractures and Greenhouse Gas Emissions, run by Karolinska Institutet at 1 site in Sweden.
Trial summary
This study examines the environmental impact of two common treatment pathways for hand fractures (metacarpal shaft fractures): surgical and non-surgical management. Healthcare contributes significantly to climate change, and orthopedic surgery in particular generates substantial greenhouse gas emissions. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Metacarpal Shaft Fractures, Greenhouse Gas Emissions
- What is being tested?
- Non-operative treatment and Surgical fixation
- Type of treatment
- Surgery or procedure
- How many people
- 30 participants
- Where
- 1 siteSweden
- Study dates
- 23 Mar 2026to Mar 2028
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: The observational cohorts will include all patients enrolled in the CARBO trial, where participants are randomized to either surgical or non-surgical management. The intervention cohort will consist of patients allocated to non-surgical management, whereas the control cohort will comprise patients allocated to surgical management.
Who may be able to join
- Age ≥18 years.
- Access to a valid e-mail.
- Injury within 10 days prior to inclusion.
- Normal bilateral hand function prior to injury.
- Ability and willingness to provide written informed consent
- Single, displaced spiral or oblique diaphyseal fracture of the second to fifth metacarpals with definition of diaphysis as described by AO 2018 (AO/OTA as 77.2-5.2A) (Meinberg et al., 2018).
- Fracture line length at least twice the diameter of the bone at the level of the fracture.
- Fractures with at least 2 mm of radiological displacement and/or malrotation of injured finger compared to uninjured side regardless of fracture displacement.
Who cannot join
- The patient is not expected to have difficulty adhering to the study protocol (e.g., due to insufficient language proficiency, dementia, substance abuse, or other reasons).
- The patient does not have an open fracture (Gustilo-Anderson grade > I) or a pathological fracture.
- The patient does not have an ipsilateral fracture of the upper extremity, polytrauma, or generalized joint dysfunction (e.g., rheumatoid arthritis).
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Sweden1 site, 1 recruiting
- Recruiting
Karolinska Institutet, Danderyd's hospital
Stockholm, Stockholm County, 18288
Cecilia Mellstrand Navarro, MD, Ass Professor, +46 709 280114, cecilia.mellstrand.navarro@ki.se
Elsa Pihl, MD, PhD, +46739705669, elsa.pihl@ki.se
About this study
Official title: The CARBO CARBON Study: a Prospective Observational Comparative Cohort Study on Environmental Impact From Two Metacarpal Shaft Fracture Treatment Pathways
This study examines the environmental impact of two common treatment pathways for hand fractures (metacarpal shaft fractures): surgical and non-surgical management. Healthcare contributes significantly to climate change, and orthopedic surgery in particular generates substantial greenhouse gas emissions. Although surgical treatment is frequently favored for these fractures, it is not always superior to non-surgical treatment, and the difference in environmental impact between these options is not well understood.
In this study, researchers will measure and compare the environmental impact of each treatment pathway, from inclusion to twelve months follow-up. This includes environmental impact related to single-use material, medical equipment, energy use, medications, and waste. A Life Cycle Assessment (LCA) will be performed and a mean difference in environmental impact between treatments pathways will be calculates. A Hotspot analysis will also be performed to highlight key sources of environmental impacts. The findings may help guide more sustainable healthcare practices without compromising patient care.
Read the detailed description
Healthcare contributes substantially to global greenhouse gas emissions, with orthopedic surgery representing a resource- and carbon-intensive part of the healthcare system. For metacarpal shaft fractures, surgical treatment is widely used despite limited evidence of superiority to non-operative management. The difference in environmental impact of the two treatment options remains unexplored.
This prospective multicenter observational comparative cohort study is conducted alongside a randomized controlled trial called the MetaCARpalBOne trial (The CARBO trial). Environmental impact will be estimated using LCA according to four standard phases: (1) goal and scope definition, (2) Life Cycle Inventory (LCI), (3) Life Cycle Impact Assessment (LCIA) and (4) interpretation including sensitivity and uncertainty analysis. All this will be based on detailed activity data for materials, energy use, pharmaceuticals and waste across the treatment pathway from inclusion in the study to 12 months post-treatment. Climate change impact will be calculated within defined system boundaries and expressed as kilograms of carbon dioxide equivalent (CO₂e) per treatment pathway. The primary outcome is the difference in mean CO₂e between treatment groups. Secondary outcomes include fine particulate matter formation, water consumption, weight of combustible waste and direct cost differences. Explorative outcomes will include all other environmental impact categories covered by the selected LCIA method and identification of major emission hotspots.
Appropriate parametric or non-parametric statistical tests will be applied to estimate the difference between treatment pathways. Normal distribution will be tested by Kolmogorov-Smirnov and Shapiro Wilk's test. If data is not normally distributed, we will present a median with a corresponding interquartile range and compare groups by Mann-Whitney U-test. To account for uncertainty both in the life cycle assessment (LCA) estimates and in the intervention effect, Monte Carlo-generated datasets will be analyzed using a linear mixed-effects modelling approach. The robustness of the results for the primary and secondary outcomes will be assessed using sensitivity analyses changing key assumptions regarding: energy mix, lifespan of products, allocations, and anesthesiology methods.
The study evaluates environmental impact and costs only and does not involve analysis of personal data. Ethical approval has been obtained from the Swedish Ethical Review Authority (DNR 2025-04413-01; amendment DNR 2025-07659-02). Results will be disseminated through peer-reviewed publications.
- Being tested
- Non-operative treatment, Surgical fixation
- Keywords
- metacarpal fractures, carbon dioxide emissions, LCA analysis, greenhouse gas emissions, carbon dioxide equivalent
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Non-operative treatmentProcedure or surgery
Non-operative treatment through immediate unrestricted mobilization with optional buddy taping or removable splinting for comfort.
Surgical fixationProcedure or surgery
Open reduction and internal fixation with plate and screws or screws only, followed by postoperative imobilisation and rehabilitation.
| Study group | Role | What they receive |
|---|---|---|
| Non operative treatment, early mobilisation | Non-operative treatment by immediate unrestricted mobilization with optional buddy taping or removable splinting for comfort Receives: Procedure: Non-operative treatment | |
| Operative treatment, open reduction and surgical fixation | Operative treatment, open reduction and surgical fixation with plate and screws or screws only, post operative plaster immobilisation followed by rehabilitation Receives: Procedure: Surgical fixation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Global warming potential
The primary outccome is global warming potential expressed as the mean carbon dioxide equivalent (CO₂e) emissions between the treatment pathways early rehabilitation without surgery and surgical treatment followed by rehabilitation of metacarpal shaft fractures. Our functional unit is defined as the full treatment pathway from inclusion in the study to 12 months post-treatment
Measured: 12 months
Secondary outcomes (4)
Ambient air pollution
The mean emission of ambient air pollution expressed as fine particle matter formation (PM2.5) for the two treatment pathways.
Measured: 12 months
Water comsumption
The mean water comsumption in cubic meters for the two treatment pathways.
Measured: 12 months
Waste
Include the total weight of combustible waste generated at each healthcare visit, measured in kilograms using a calibrated hanging scale
Measured: 12 months
Direct costs
Difference in direct costs within our study boundary between the treatment methods.
Measured: 12 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Apr 2026
- Study start23 Mar 2026
- Primary completionMar 2028 (estimated)
- Study completionMar 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Metacarpal Shaft FracturesStudies of the same condition, open and under way.
- More trials run by Karolinska InstitutetThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Karolinska Institutet
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Cecilia Mellstrand Navarro, Karolinska Institutet
- Investigators
- Cecilia Mellstrand Navarro, MD, PhD, ass professor, Principal investigator, Karolinska Institutet
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07521943
- Sponsor's protocol ID
- 2025-07659-02
- Other IDs
- 2025
- Acronym
- CARBO CARBON
- Status last verified
- Jun 2026
- First submitted
- 2 Apr 2026
- Last updated
- 4 Jun 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 4 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The CARBO CARBON Study: a Prospective Observational Comparative Cohort Study on Environmental Impact From Two Metacarpal Shaft Fracture Treatment Pathways
- ClinicalTrials.gov ID
- NCT07521943
- Acronym / sponsor ID
- CARBO CARBON / 2025-07659-02
- Keywords
- metacarpal fractures, carbon dioxide emissions, LCA analysis, greenhouse gas emissions, carbon dioxide equivalent
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Karolinska InstitutetUniversity, hospital or other
- Study start
- 23 Mar 2026 (actual)
- Primary completion
- Mar 2028 (estimated)
- Study completion
- Mar 2028 (estimated)
- First posted
- 13 Apr 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study examines the environmental impact of two common treatment pathways for hand fractures (metacarpal shaft fractures): surgical and non-surgical management. Healthcare contributes significantly to climate change, and orthopedic surgery in particular generates substantial greenhouse gas emissions. Although surgical treatment is frequently favored for these fractures, it is not always superior to non-surgical treatment, and the difference in environmental impact between these options is not well understood.
In this study, researchers will measure and compare the environmental impact of each treatment pathway, from inclusion to twelve months follow-up. This includes environmental impact related to single-use material, medical equipment, energy use, medications, and waste. A Life Cycle Assessment (LCA) will be performed and a mean difference in environmental impact between treatments pathways will be calculates. A Hotspot analysis will also be performed to highlight key sources of environmental impacts. The findings may help guide more sustainable healthcare practices without compromising patient care.
Detailed description
Healthcare contributes substantially to global greenhouse gas emissions, with orthopedic surgery representing a resource- and carbon-intensive part of the healthcare system. For metacarpal shaft fractures, surgical treatment is widely used despite limited evidence of superiority to non-operative management. The difference in environmental impact of the two treatment options remains unexplored.
This prospective multicenter observational comparative cohort study is conducted alongside a randomized controlled trial called the MetaCARpalBOne trial (The CARBO trial). Environmental impact will be estimated using LCA according to four standard phases: (1) goal and scope definition, (2) Life Cycle Inventory (LCI), (3) Life Cycle Impact Assessment (LCIA) and (4) interpretation including sensitivity and uncertainty analysis. All this will be based on detailed activity data for materials, energy use, pharmaceuticals and waste across the treatment pathway from inclusion in the study to 12 months post-treatment. Climate change impact will be calculated within defined system boundaries and expressed as kilograms of carbon dioxide equivalent (CO₂e) per treatment pathway. The primary outcome is the difference in mean CO₂e between treatment groups. Secondary outcomes include fine particulate matter formation, water consumption, weight of combustible waste and direct cost differences. Explorative outcomes will include all other environmental impact categories covered by the selected LCIA method and identification of major emission hotspots.
Appropriate parametric or non-parametric statistical tests will be applied to estimate the difference between treatment pathways. Normal distribution will be tested by Kolmogorov-Smirnov and Shapiro Wilk's test. If data is not normally distributed, we will present a median with a corresponding interquartile range and compare groups by Mann-Whitney U-test. To account for uncertainty both in the life cycle assessment (LCA) estimates and in the intervention effect, Monte Carlo-generated datasets will be analyzed using a linear mixed-effects modelling approach. The robustness of the results for the primary and secondary outcomes will be assessed using sensitivity analyses changing key assumptions regarding: energy mix, lifespan of products, allocations, and anesthesiology methods.
The study evaluates environmental impact and costs only and does not involve analysis of personal data. Ethical approval has been obtained from the Swedish Ethical Review Authority (DNR 2025-04413-01; amendment DNR 2025-07659-02). Results will be disseminated through peer-reviewed publications.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Non operative treatment, early mobilisation | – | Procedure: Non-operative treatmentNon-operative treatment by immediate unrestricted mobilization with optional buddy taping or removable splinting for comfort |
| Operative treatment, open reduction and surgical fixation | – | Procedure: Surgical fixationOperative treatment, open reduction and surgical fixation with plate and screws or screws only, post operative plaster immobilisation followed by rehabilitation |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- The observational cohorts will include all patients enrolled in the CARBO trial, where participants are randomized to either surgical or non-surgical management. The intervention cohort will consist of patients allocated to non-surgical management, whereas the control cohort will comprise patients allocated to surgical management.
Key inclusion criteria (8 listed)
- Age ≥18 years.
- Access to a valid e-mail.
- Injury within 10 days prior to inclusion.
- Normal bilateral hand function prior to injury.
- Ability and willingness to provide written informed consent
Key exclusion criteria (3 listed)
- The patient is not expected to have difficulty adhering to the study protocol (e.g., due to insufficient language proficiency, dementia, substance abuse, or other reasons).
- The patient does not have an open fracture (Gustilo-Anderson grade > I) or a pathological fracture.
- The patient does not have an ipsilateral fracture of the upper extremity, polytrauma, or generalized joint dysfunction (e.g., rheumatoid arthritis).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Non-operative treatmentNon-operative treatment through immediate unrestricted mobilization with optional buddy taping or removable splinting for comfort. | Procedure or surgery | Non operative treatment, early mobilisation |
| Surgical fixationOpen reduction and internal fixation with plate and screws or screws only, followed by postoperative imobilisation and rehabilitation. | Procedure or surgery | Operative treatment, open reduction and surgical fixation |
Primary outcome
Global warming potential
Time frame: 12 months
The primary outccome is global warming potential expressed as the mean carbon dioxide equivalent (CO₂e) emissions between the treatment pathways early rehabilitation without surgery and surgical treatment followed by rehabilitation of metacarpal shaft fractures. Our functional unit is defined as the full treatment pathway from inclusion in the study to 12 months post-treatment
4 secondary outcomes
Ambient air pollution
Time frame: 12 months
Water comsumption
Time frame: 12 months
Waste
Time frame: 12 months
Direct costs
Time frame: 12 months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Jun 2026.
- Individual participant dataSharing planned: Undecided
Related trials for Metacarpal Shaft Fractures
Recruiting
metaCARpal Bone Osteosynthesis Trail
Metacarpal Shaft Fractures
Recruiting
Buddy Tape vs. Splint for Metacarpal Shaft Fracture Recovery
Non-thumb Metacarpal Shaft Fracture
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Cecilia Mellstrand Navarro, MD, PhD, ass professor principal investigator
Karolinska Institutet
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Metacarpal Shaft Fractures and Greenhouse Gas Emissions, run by Karolinska Institutet at 1 site in Sweden.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 4 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Sweden. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Cecilia Mellstrand Navarro, MD, PhD (+46709280114, cecilia.mellstrand.navarro@ki.se), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Global warming potential (time frame: 12 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Jun 2026.