Bracey DN, Hegde V, Pollet A, et al. - After total knee arthroplasty (TKA), post-operative urinary retention (POUR) may cause urologic injury and delay patient discharge. This study was undertaken to investigate the incidence of POUR and distinguish predictive risk factors. The researcher prospectively recruited a total of 271 consecutive patients undergoing primary unilateral TKA. They conducted bladder scans in the PACU and every four hours thereafter. Univariate and multivariate logistic regression analyses were applied to evaluate patient demographics, urologic history, operative data, perioperative medications, and bladder scanner volumes. After TKA, a significant percentage of patients develop POUR. The data considered that select patient demographics and PACU bladder scanning may distinguish those at risk. The outcomes revealed that appropriate pain control and judicious use of perioperative NSAIDs and glycopyrrolate may help minimize the risk of POUR.