Method

A prospective observational study involving 63 patients undergoing primary shoulder arthroplasty was designed. In all patients two skin biopsies with a 3 mm dermal punch and one subcutaneous tissue sample after surgical incision were obtained. Skin biopsies were obtained at the most anterior part of the surgical wound in case of superior approach and at the upper part in the deltopectoral approach. All patients underwent preoperative antibiotic prophylaxis with cefazolin 2g ev and skin preparation with 2% chlorhexidine alcoholic tinted before the start of surgery twice. The aerobic cultures were incubated at 37ºC for 7 days whereas the anaerobic ones incubated for 14 days.