Randomized controlled trial of chlorhexidine wash versus benzoyl peroxide soap for home surgical preparation: neither is effective in removing Cutibacterium from the skin of shoulder arthroplasty patients

Introduction Home chlorhexidine washes prior to shoulder surgery are commonly used in an attempt to reduce the skin bacterial load. However, recent studies have suggested that this agent is relatively ineffective against Cutibacterium acne. Benzoyl peroxide soap is a treatment for acne, but evidence regarding its effectiveness as prophylaxis in shoulder surgery is lacking. Therefore, the objective of this study was to compare the effectiveness of home chlorhexidine washes with benzoyl peroxide soap (BPO) in patients undergoing shoulder arthroplasty surgery in reducing Cutibacterium levels on the skin surface and in the dermis. Methods Fifty male patients planning to undergo shoulder arthroplasty were consented to be randomized into treatment with 4% chlorhexidine solution (CHG) and 10% benzoyl peroxide soap (BPO) used to wash the operative shoulder the night prior and morning of surgery. Skin swabs prior to incision and dermal wound swabs after incision were obtained, and the bacterial load was reported in a semiquantitative manner as the Specimen Cutibacterium Value (SpCuV). The two groups were compared with regards to the percent positivity of the skin surface and incised dermal edge as well as the bacterial load at each site. Results Skin surface swabs were positive in 100% of patients using CHG and 100% of patients using BPO soap. The Cutibacterium load (SpCuV) on the skin surface was similar between the two groups (CHG 1.6 +/- 1.1 vs. BPO 1.5 +/- 1.4, p = 0.681). The percentages of dermal cultures that were positive were not significantly different between the two groups (CHG 61% vs BPO 46%, p = 0.369). The Cutibacterium load (SpCuV) on the incised dermal edge was similar between the two groups (CHG 0.8 +/- 1.0 vs. BPO 0.8 +/- 1.4, p = 0.991). Discussion Neither BPO soap nor chlorhexidine washes prior to shoulder surgery were effective in eliminating Cutibacterium from the skin surface or the incised dermal edge. Further study of means of reducing the Cutibacterium load of the skin at the time of shoulder arthroplasty is warranted.