USE LESS, a Comparative Cohort Study of Climate Change Impact From Orthopedic Surgery

Background: Human health depends on the stability of Earth's ecological systems. Healthcare, guided by the principle "first do no harm," paradoxically contributes to this destabilization: globally, it accounts for \~5% of greenhouse gas (GHG) emissions, with orthopedic care among the most resource-intensive domains. It is imperative that the health sector finds ways to reduce emissions while still providing care with preserved quality and quantity. Use of single-use materials has been found to yield a significant part of emissions from orthopedic surgeries. Performing minor surgeries in procedure rooms instead of the operating room can reduce emissions and waste. Moreover, a small portion of products accounts for most of an operation's carbon footprint, suggesting that targeted measures may have substantial impact.

Carbon emission represents only one dimension of healthcare's environmental burden. Life Cycle Assessment (LCA) enables quantification of impacts across categories such as toxicity, particulate matter formation, resource depletion, water consumption, land use, ozone formation, and ecosystem effects. These categories are relevant in orthopedics, where products commonly contain e.g. polyvinyl chloride (PVC), di(2-ethylhexyl) phthalate (DEHP), and per- and polyfluoroalkyl substances (PFAS). Moreover, large quantities of nonrecyclable plastics are used. Transitioning from single-use to reusable products can reduce GHG emissions significantly, though further studies are needed to ensure clinical safety.

Carbon emission represents only one dimension of healthcare's environmental burden. Life Cycle Assessment (LCA) enables quantification of impacts across categories such as toxicity, particulate matter formation, resource depletion, water consumption, land use, ozone formation, and ecosystem effects. These categories are relevant in orthopedics, where products commonly contain e.g. polyvinyl chloride (PVC), di(2-ethylhexyl) phthalate (DEHP), and per- and polyfluoroalkyl substances (PFAS). Moreover, large quantities of nonrecyclable plastics are used \[9\]. Transitioning from single-use to reusable products can reduce GHG emissions significantly, though further studies are needed to ensure clinical safety. Population: Age ≥18 years undergoing release of carpal tunnel or trigger finger, wound revision or amputation of finger or toe, extraction of osteosynthesis material or suturing of extensor tendon (hand or foot) at Danderyd's Hospital. There are no exclusion criteria.

Intervention: Procedures performed in a procedure room using a reduced material set at the outpatient clinic under local anesthetics only. Control: Procedures performed in an operating room (OR) using a standard OR set up with available anesthesiology assistance.

This study hopes to answer the question: How do climate change impact differ between minor orthopedic procedures performed in a conventional operating theatre compared with procedures in an outpatient clinic procedure room with a reduced set of material?

Primary outcome: CO₂e per functional unit. Secondary outcomes: Complications (infection, readmission), combustible waste (kg) and costs (staff and material). Hotspot analysis identifying major contributors to emissions. The functional unit is defined as one performed surgery.

Environmental impacts will be assessed using Life Cycle Assessment (LCA) according to the 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 analyses. System boundaries will be cradle-to-grave when complete data are available and otherwise gate-to-gate for single-use products lacking published LCAs. Identical system boundaries will be applied within each study to ensure comparability between intervention and control groups. Life cycle inventories will include materials, pharmaceuticals, reusable and single-use equipment, sterilization, energy consumption, waste handling, inpatient care, and staffing. Detailed inventories of surgical procedures will be collected prospectively at Danderyd Hospital, including article numbers, quantities, and weights of materials, as well as disposal weights. CO₂e emissions will primarily be calculated using manufacturer LCAs; where unavailable, emissions will be estimated from material composition and weight using established databases (e.g., Inventory of Carbon and Energy) and published templates for reusable materials and energy use. Mean emissions per procedure or treatment pathway will be calculated and compared between groups.

• Readmission [Time frame: within 90 days of the performed sugery]
• Combustible waste [Time frame: All consecutive suergeries for twelve months in each group]
• Costs [Time frame: All consecutive suergeries for twelve months in each group]
• Infections [Time frame: Within 90 days of surgery]