Pre- and peroperative diagnosis of Cutibacterium acnes infections in shoulder surgery: A systematic review

Background: Cutibacterium acnes is the most commonly detected pathogen during shoulder surgery. Lack of typical infection signs make Cutibacterium acnes infections difficult to diagnose. This systematic review aims to determine which pre- and peroperative diagnostic tools are most reliable to identify Cutibacterium acnes infections after shoulder surgery.Methods: PubMed/Embase were searched for diagnostic studies. Methodological quality of included studies was assessed using QUADAS-2. Forest plots summarized results (sensitivity and specificity) for each pre- and peroperative diagnostic tool.Results: Twenty-two studies were included, of which 8 described preoperative, 10 peroperative, and 4 both pre- and peroperative diagnostic tools. Quality of the studies varied widely. For preoperative tools, synovial calprotectin, interleukin-6, and combined interleukin-6/interleukin-2/tumor necrosis factor-alpha had the best efficacy measures. Pre-revision biopsies and arthroscopic tissue cultures were the best peroperative tools.Conclusion: Despite a lack of evidence and the use of different Cutibacterium acnes infection criteria and reference standards, the use of combined interleukin-6/interleukin-2/tumor necrosis factor-alpha as preoperative and arthroscopic tissue cultures as peroperative diagnostic tool is for now recommended based on results and validity. More research should be performed to provide valid evidence on these tools. In order to do so, an internationally accepted definition of Cutibacterium acnes infections is essential.Level of evidence: Systematic review.