Hipfl C, Mooij W, Perka C, et al. - Researchers aimed at determining unexpected positive cultures in total hip arthroplasty (THA) revisions for presumed aseptic loosening. They investigated the prevalence of low-grade infection using two definition criteria, and analyzed its influence on implant survival after revision. Among a total of 274 THA reviewed revisions carried out for presumed aseptic loosening from 2012 to 2016, 77 (28%) had unexpected positive intraoperative samples. Thirty six cases (13%) of low-grade infection were identified using institutional criteria and nine cases (3%) were identified using MSIS ICM 2013 criteria. The most commonly isolated bacteria were coagulase-negative Staphylococcus and anaerobes. Per these findings, the presumption of culture contamination in aseptic revision hip arthroplasty may improve the detection of PJI. This cohort had no increase in the risk of re-revision because of the presence of low-grade infection.