Microbial colonization of subscapularis tagging sutures in shoulder arthroplasty: a prospective, controlled study

Background Reducing intraoperative wound contamination is a critical preventive strategy for reducing the risk of prosthetic joint infection in shoulder arthroplasty. The aim of this study was to investigate the potential microbial colonization of subscapularis tagging sutures during shoulder arthroplasty. Methods In this prospective study, 50 consecutive patients undergoing primary shoulder arthroplasty (anatomic or reverse) were enrolled. Patients with revision shoulder arthroplasty and proximal humeral fractures were excluded. Nonabsorbable, braided tagging sutures were placed through the subscapularis tendon prior to tenotomy. A similar nonabsorbable, braided suture (control) was placed in a sterile container on the back table, open to the operating room environment. Subscapularis tagging sutures (experimental specimens) and control sutures were collected prior to subscapularis tenotomy repair and submitted for aerobic and anaerobic cultures. Cultures were held for 21 days to account for extended growth of slow-growing bacteria. Results A total of 12 of 50 experimental and 16 of 50 control sutures had positive cultures. Staphylococcus epidermidis and Cutibacterium acnes were the 2 most commonly isolated organisms. Active tobacco use ( P = .038) and procedure length ( P = .03) were significantly associated with positive cultures. No significant association between positive subscapularis tagging suture cultures and positive control cultures was found ( P = .551). Patient age, sex, body mass index, and significant medical comorbidities were not significantly associated with positive cultures. Discussion Subscapularis tagging sutures are a potential source of microbial contaminant in shoulder arthroplasty, and we recommend exchanging the tagging suture with a suture opened immediately prior to subscapularis repair.