The carbon footprint of total knee replacements

Objective Detailed quantifications of the environmental footprint of operations that include surgery, anaesthesia, and engineering are rare. We examined all such aspects to find the greenhouse gas emissions of an operation.Methods We undertook a life cycle assessment of 10 patients undergoing total knee replacements, collecting data for all surgical equipment, energy requirements for cleaning, and operating room energy use. Data for anaesthesia were sourced from our prior study. We used life cycle assessment software to convert inputs of energy and material use into outputs in kg CO2e emissions, using Monte Carlo analyses with 95% confidence intervals.Results The average carbon footprint was 131.7 kg CO2e, (95% confidence interval: 117.7-148.5 kg CO2e); surgery was foremost (104/131.7 kg CO2e, 80%), with lesser contributions from anaesthesia (15.0/131.7 kg CO2e, 11%), and engineering (11.9/131.7 kg CO2e, 9%). The main surgical sources of greenhouse gas emissions were: energy used to disinfect and steam sterilise reusable equipment (43.4/131.7 kg CO2e, 33%), single-use equipment (34.2/131.7 kg CO2e, 26%), with polypropylene alone 13.7/131.7 kg CO2e (11%), and the knee prosthesis 19.6 kg CO2e (15%). For energy use, the main contributors were: gas heating (6.7 kg CO2e) and heating, cooling, and fans (4 kg CO2e).Conclusions The carbon footprint of a total knee replacement was equivalent to driving 914 km in a standard 2022 Australian car, with surgery contributing 80%. Such data provide guidance in reducing an operation's carbon footprint through prudent equipment use, more efficient steam sterilisation with renewable electricity, and reduced single-use waste.