In this study the waste from six common orthopaedic procedures and its associated carbon footprint was quantified, and possible strategies for waste reduction were identified. The mean weight of the waste generated by the included orthopaedic procedures was 7.66 kg and the mean environmental impact was 22.20 kg CO2-eq. Waste is one of the areas over which hospitals have significant influence to reduce the environmental impact, as was shown in our study by the observed 10.34–13.89 kg CO2-Eqs. (48–63%) reduction.

Several studies have explored the waste generated during TKA and THA [13,14,15,16,17,18,19, 22, 23]. Common strategies to reduce the environmental impact include increase of recycling [13,14,15,16,17,18,19], replacing disposables with reusables [13, 19], precision-based technologies to minimise the over-selection of implants [22, 23], and updating the procedure trays regularly [17]. Our findings align with these strategies. However, the reported potential for waste reduction across studies varied significantly. This variability can be attributed to differences in the inclusion and exclusion criteria of categories of waste. For example, some studies included clinical hazardous waste (for example blood) in their assessments [13, 14], which contributed to higher reported reduction outcomes. Differences in surgical technique, instruments, and materials used across studies may also explain this variability.

Our findings highlight the possibility to reduce waste using waste reduction strategies in hospitals, as it represents an effective area for improving the environmental sustainability of orthopaedic procedures that can directly be implemented. This represents a practical and effective opportunity to enhance the environmental sustainability of orthopaedic procedures.

A strength of the HSMEA method is that it can effeciently reduce environmental impact and aligns well with the aim of this study, which was to quantify waste from orthopaedic procedures and identify potential strategies for its reduction. The HSMEA has the advantage of allowing for quick identification and direct implementation of sustainable changes in practice. To the best of our knowledge this study was to first study to perform a waste audit using the validated HSMEA method and to implement the changes in clinical practice.

An example of a change we implemented was switching from cemented UKA to uncemented UKA, based on our findings that removing certain items from our procedural pack would lower the environmental impact of the waste (-2.624 g CO2-eq.). However, generating less waste does not necessarily equate to a lower overall environmental impact. While our results showed that uncemented UKA generated less waste, this comparison did not account for other contributing factors. In only three articles it was addressed whether cemented or uncemented implants were used and none directly compared the waste generated by each type [13, 18, 19]. A complete LCA that accounts for the production of both implant types would be necessary to accurately evaluate their environmental footprints in detail. It is also important to note that the eventual choice between implant types should be guided primarily by clinical judgment and patient-specific factors. Sustainability should be considered when both options are clinically equivalent.

This study was limited to six common orthopaedic procedures. These procedures were selected with the expectation that they would offer significant potential for waste reduction. While this study quantifies the waste generated by these procedures, it does not provide a comprehensive assessment of waste production across all orthopaedic procedures. We expect that orthopaedic procedures not included, would produce a similar or smaller amounts of waste. Furthermore, techniques, instruments and materials vary between hospitals. Due to variability in organisation between hospitals, achieving the same level of waste reduction may not be feasible at every centre. While our results account specifically for our hospital, they highlight the potential for reducing carbon dioxide emissions in orthopaedic surgery. This study offers a method that can be used in all centres to monitor and reduce the weight and environmental impact of the waste of orthopaedic and other procedures.

We found minimal variation in the items used across procedures, which can be explained by the high standardization of arthroplasty procedures. Differences in weight of the waste within the same procedure were primarily due to differences in bloody gauzes, surgical gloves, and the protective equipment worn by surgical observers (residents and students), which can differ regardless of procedure type. Given our aim to identify strategies to reduce the environmental impact of six common highly standardized orthopaedic procedures, we believe the number of procedures analysed to be sufficient.

To calculate the environmental impact, an upcycling credit was applied. A positive credit (+) was used to account for environmental savings, even though the actual recycling and incineration of waste occurred ouside our direct supply chain. This approach allowed us to highlight the difference in environmental impact between recycling and incineration.

This study, along with previous research, highlights the possibility and need to reduce waste in orthopaedic procedures. We found that some items were included in the procedure setup out of routine rather than necessity. Promoting a culture of sustainability is crucial, as operating room staff are well placed to identifyand eliminate unnecessary waste.

Efforts should focus on avoiding unnecessary materials, such as surgical instrument sets, since their packaging of sets contributes to waste [24,25,26]. Wherever possible, disposable items should be replaced with reusables. Ultimately, the most sustainable approach to healthcare is to reduce unnecessary operative care whenever possible.

Hospitals should adopt and implement comprehensive sustainable waste management strategies across their operations. These strategies include refusing unnecessary items, reassessing the need for certain materials, reusing when safe, reducing overall volume, avoiding single-use items when alternatives exist, and actively recycling. The strategies should be applied regularly, as new research and innovations in sustainable alternatives continue to emerge. To effectively drive sustainability, hospitals should collaborate closely with their staff, industry partners, institutions, and government agencies. By fostering these partnerships and embracing ongoing change, hospitals can continally reduce their environmental footprint.