Cutibacterium acnes (C. acnes) prosthetic joint infection is a devastating and somewhat unique complication to shoulder arthroplasty. It is a very slow-growing, aerotolerant anaerobic, non-spore forming, gram-positive rod-shaped bacteria that takes up to 2-3 weeks to grow in a lab setting. There have been several studies assessing various agents in the fight to prevent C. acnes prosthetic joint infection. These agents include standard peri-operative measures typically taken when performing shoulder replacement surgery - pre-operative prophylactic antibiotics, pre-operative skin cleanse/wash, topical adjuvants (povidone-iodine, chlorhexidine, etc.), and intra-operative antibiotic powders. The overall infection rate of shoulder arthroplasty has been cited to be between 0.9-2.9%, with C. acnes being the most common bacterium in shoulder arthroplasty periprosthetic infections. Morbidity and cost associated with shoulder prosthetic joint infection is extremely high, requiring multiple surgeries and months of treatment to overcome the infection.

One of the main issues with C. acnes is its preferred location within the body, residing within the sebaceous glands of the hair follicles, deep to the epidermis where many preoperative topical preparations to cleanse the skin prior to surgery have little affect. These glands are commonly found around the shoulder and upper back, and lead to acne. C. acnes, along with other common prosthetic joint infection bacteria, quickly create a biofilm which is impenetrable to most antibiotic agents, further stressing the importance of prevention. Recently there have been studies analyzing the effects of Benzoyl Peroxide (BPO) on C. acnes as it relates to shoulder arthroplasty in an attempt to reduce this bacterial burden prior to surgery. There have been promising results with multi-day preparation skin cleansing with benzoyl peroxide. However, there are no studies looking at intra-operative skin incision preparations targeting the region of skin where the C. acnes bacteria resides. In vitro studies show SURGX antimicrobial gel (Next Science, Jacksonville, FL) results in a marked reduction of C. acnes in addition to other common bacteria affecting prosthetic joints. This gel uses citric acid to chelate the metallic bonds of biofilm. The bacteria are then destroyed by a combination of a high osmolarity environment coupled with a surfactant.

The first purpose of the study is to evaluate if a dermal layer preparation will reduce positive cultures of C. acnes after primary shoulder arthroplasty. There will be a control group consisting of no skin preparation. There will be two additional comparative groups. The second purpose of this study is to compare the use of standard povidone-iodine swab versus SURGX antimicrobial gel as an application into the dermal layer after the skin incision has been made with a skin knife to see if there is a reduction in bacterial burden in the superficial and deep tissues at the end of a primary shoulder arthroplasty. Superficial and deep cultures will be obtained at the conclusion of the shoulder replacement surgery. These cultures will be held in the lab for 2 weeks to identify if bacteria is present. The study team's hypothesis is that the SURGX antimicrobial gel will provide a greater reduction in bacterial burden compared to povidone-iodine within the deep tissues after primary shoulder arthroplasty.