The CARBO CARBON Study: a Prospective Observational Comparative Cohort Study on CO2 Emissions From Metacarpal Shaft Fracture Treatment
Overview
- Phase
- Not Applicable
- Status
- Recruiting
- Sponsor
- Karolinska Institutet
- Enrollment
- 30
- Locations
- 1
- Primary Endpoint
- Carbon dioxide equivalent
Overview
Brief Summary
This study examines the environmental impact of two common treatments for hand fractures (metacarpal shaft fractures): surgery and non-surgical care. Healthcare contributes significantly to climate change, and orthopedic surgery in particular can generate substantial greenhouse gas emissions. Although surgery is frequently used for these fractures, it is not always clearly more effective than 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 carbon footprint of each treatment pathway, from injury through one year of follow-up. This includes emissions related to medical equipment, energy use, medications, and waste. The goal is to calculate the difference in environmental impact between treatments and to highlight key sources of emissions. The findings may help guide more sustainable healthcare practices without compromising patient care.
Detailed Description
Healthcare contributes substantially to global greenhouse gas emissions, with orthopaedic 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 over non-operative management. The difference in environmental impact of the two treatment options remains unexplored.
This prospective multicentre observational comparative cohort study is conducted alongside a randomized controlled trial (The CARBO trial). Carbon emissions will be estimated using mainly a carbon foot printing bottom-up approach based on detailed activity data for materials, energy use, pharmaceuticals and waste across the treatment pathway from injury to 12 months post-treatment. Where a bottom-up approach is unavailable, an environmentally extended input-output (EEIO) model will be applied. Emissions will be calculated within defined system boundaries within Scopes 2 and 3 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 waste generation, emission hotspots and direct cost differences. Appropriate parametric or non-parametric statistical tests will be applied to estimate the differences between treatments. The robustness of the primary outcome (CO₂e emissions) will be evaluated using one-way sensitivity analyses and scenario analyses in which key model parameters are varied.
The study evaluates environmental impact 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
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Parallel
- Primary Purpose
- Other
- Masking
- None
Eligibility Criteria
- Ages
- 18 Years to — (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •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.
Exclusion Criteria
- •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).
Arms & Interventions
Non operative treatment, early mobilisation
Non-operative treatment by immediate unrestricted mobilization with optional buddy taping or removable splinting for comfort
Intervention: Non-operative treatment (Procedure)
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
Intervention: Surgical fixation (Procedure)
Outcomes
Primary Outcomes
Carbon dioxide equivalent
Time Frame: 12 months
The primary outccome is the difference in 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 injury to 12 months post-treatment
Secondary Outcomes
- Direct costs(12 months)
- Waste(12 months)
- Emission hotspots(12 months)
Investigators
Cecilia Mellstrand Navarro
MD, ass professor
Karolinska Institutet