The purpose of this study is to compare the growth of intra-operative tissue cultures of Cutibacterium Acnes after primary shoulder replacement when using a no-prep control group versus Prontosan wound gel applied to the skin layer after the skin incision has been made.

60 male patients undergoing primary anatomic or reverse shoulder arthroplasty will be enrolled in this prospective, randomized controlled trial evaluating the use of Prontosan wound gel versus no preparation to the dermal layer of skin after incision has been made. Participants will be randomly assigned to one of two groups of 30 patients: control (no post-incision dermal preparation) and Prontosan antimicrobial gel application to the dermal layer after skin incision. All patients, regardless of assignment, receive the same pre-incision skin preparations, prophylactic antibiotics, and intraoperative irrigation. After final implantation and before wound closure, culture swabs will be obtained (2 deep cultures, 2 superficial, and 1 implant). All cultures will be held in the lab for 2 weeks to monitor for growth of C. acnes.

Inclusion Criteria:

• Adult male 18 years of age or older undergoing elective primary total shoulder arthroplasty, including both anatomic and reverse total shoulder arthroplasty, for indications including massive rotator cuffs, rotator cuff arthropathy, glenohumeral osteoarthritis, and acute fractures.

Exclusion Criteria:

• Any revision shoulder arthroplasty procedure or other shoulder surgery that is not a primary shoulder arthroplasty.
• Patients with allergy to active ingredients in Prontosan gel
• Patient is unable to consent for themselves
• Patient is non-English speaking
• Females