Topical Preparations for Reducing Cutibacterium acnes Infections in Shoulder Surgery: A Systematic Review and Network Meta-analysis of Randomized Controlled Trials

Background: Cutibacterium acnes ( C acnes) is a commensal skin bacterium, primarily found in sebaceous glands and hair follicles, with a high prevalence in the shoulder region. It is the most common pathogenic organism in prosthetic joint infections after shoulder arthroplasty. Because of its low virulence, its diagnosis remains difficult. Purpose: To evaluate the relative effects of topical preparations in reducing C acnes in shoulder surgery. Study Design: Meta-analysis; Level of evidence, 1. Methods: We searched the MEDLINE, Embase, PsychINFO, and Cochrane Library databases in March 2022. Randomized controlled trials (RCTs) comparing any form of topical preparation in arthroscopic or open shoulder surgery were included. The primary outcome was a reduction in the number of positive C acnes cultures. Secondary outcomes were adverse events related to the application of topical preparations. We performed a network meta-analysis to facilitate simultaneous comparisons between multiple preparations across studies. We calculated differences between preparations using odds ratios and their 95% CIs. The risk of bias was assessed using the Cochrane risk-of-bias tool. Results: The search yielded 17 RCTs (1350 patients), of which 9 were suitable for the network meta-analysis (775 patients). Overall, 2 RCTs were deemed as having a low risk of bias, and 15 raised “some concerns” of bias. Preparations included benzoyl peroxide (BPO), BPO combined with clindamycin, chlorhexidine gluconate, hydrogen peroxide, povidone-iodine, and water with soap. Only BPO resulted in significantly lower odds of a positive C acnes culture compared with placebo or soap and water (odds ratio, 0.12 [95% CI, 0.04-0.36]). There was no statistically significant difference with all other topical preparations. The only adverse events were skin irritation from BPO and chlorhexidine gluconate in a small number of reported cases. Conclusion: BPO was the most effective topical agent in reducing the prevalence of C acnes in shoulder surgery. These results were limited by a combination of indirect and direct data. Future studies should focus on establishing the optimal frequency and duration of preoperative BPO to further reduce the burden of C acnes. Registration: CRD42022310312 (PROSPERO).