Background: Surgical site infection (SSI) remains a concern in shoulder surgery, especially during arthroplasty. Whilemany studies have explored the characteristics and efficacy of different sterilizing solutions, no study has evaluated themethod of application. The purpose of this study was to compare two popular pre-surgical preparatory applications (two4 x 4 cm gauze sponges and applicator stick) in their ability to cover the skin of the shoulder.Methods: Two orthopedic surgeons simulated the standard pre-surgical skin preparation on 22 shoulders of volunteersubjects. Each surgeon alternated between an applicator stick and two sterile 4x4 cm gauze sponges. Skin preparationwas performed with a commercially available solution that can be illuminated under UV-A light. Advanced imageanalysissoftware was utilized to determine un-prepped areas. A two-tailed paired t-test was performed to comparepercentage of un-prepped skin.Results: The applicator stick method resulted in a significantly higher percentage of un-prepped skin (27.25%, Range10-49.3) than the gauze sponge method (15.37%, Range 5-32.8, P=0.002). Based on image evaluation, most unpreppedareas were present around the axilla.Conclusion: Based on our findings, the use of simple gauze sponges for pre-surgical preparatory application ofsterilization solution may result in a lower percent of un-prepped skin than commercially available applicator stick.Orthopaedic surgeons and operating room staff should be careful during the pre-surgical sterile preparation of theshoulder, especially the region around the axilla, in order to reduce the potential risk of surgical site infection.
