Objectives
Shoulder arthroplasty has a large environmental impact. Part of the environmental impact is caused by the sterilisation of surgical instruments. This study examines the effect of optimising surgical instrument trays for reverse shoulder arthroplasty (RSA), to reduce the environmental impact.

Methods
An adjusted LEAN 5s method was used to optimise the number of instruments of shoulder arthroplasty specific trays. A Life Cycle Assessment was performed to calculate the CO2-eq.

Results
After careful selection, 139 of the 254 (55%) instruments were removed from the original RSA trays. Out of the 139 removed instruments, 19 were placed in a supplemental tray. The number of base trays was reduced with 3 trays. The estimated impact by reducing these trays from the standard pre-operative setup is a reduction of 28% of the environmental impact annually (524 kg CO2 equivalent).

Discussion
This study confirms the feasibility of optimising instrument trays for RSA, offering a straightforward method to reduce the environmental impact of shoulder arthroplasty. Our results show that strategic instrument selection can contribute to lowering the environmental impact of orthopaedic surgery.